Level IV Clinical Treatment - Unit B__formatted_raw__v1

{{PAGE_1}} LEVEL IV · CLINICAL TREATMENT

Unit B

To Extract or Not To Extract Part 2 · Special Considerations in Orthodontics for Adults · Complex Adjunctive Treatment · Orthodontic Retention

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Contents

1. To Extract or Not To Extract Part 2
2. Special Considerations in Orthodontics for Adults
3. Complex Adjunctive Treatment
4. Orthodontic Retention

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1. To Extract or Not To Extract Part 2

Background

Reasons for Extraction: Orthodontic Camouflage

There are two reasons for extracting teeth in orthodontic treatment:

• correction of crowding/protrusion
• camouflage of jaw discrepancy

It is important to keep the difference in mind—which can be confusing because some patients with a skeletal problem (mandibular deficiency, for instance) also have crowded teeth.

This module focuses on the possibilities of extraction of teeth for camouflage of skeletal Class II and Class III malocclusions. Part 1 reviews extraction for crowding/protrusion in skeletal Class I patients.

Possibilities for Treatment of Skeletal Problems: Growth Guidance

Malocclusion caused by jaws that are not aligned correctly is defined as skeletal malocclusion. The term indicates that the problem is the jaw relationship, not the way the teeth are aligned. The most

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{{PAGE_4}} common skeletal malocclusion is Angle’s Class II, in which the upper incisors protrude, usually because of less mandibular than maxillary growth. Skeletal Class III, of course, is just the reverse, and there also are skeletal vertical (open bite/deep bite) and transverse (crossbite) problems.

An important concept: If the jaws are not in a correct relationship, there are three treatment possibilities:

1. Guide growth so the deficient jaw catches up, and a normal jaw relationship is produced.

That, of course, is the ideal treatment approach, and it always should be used until there no longer is the possibility of enough correction from differential growth. This patient’s treatment to correct her Class II malocclusion succeeded because her lower jaw grew more than the upper.

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{{PAGE_5}} Image 1, pre-tx: Age 11, prior to treatment for a skeletal Class II problem. Image 2, post-tx: Age 14, after two-stage treatment and successful growth modification. Image 3, comparison: Pre-/posttreatment, successful growth modification.

Possibilities for Treatment of Skeletal Problems: Camouflage

Treatment possibilities for skeletal problems:

1. Growth modification so that the deficient jaw catches up.

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{{PAGE_6}} 2. Orthodontic camouflage, which is based on making the teeth fit in spite of the fact that the jaws don’t. This approach carries with it the idea that the jaw discrepancy will not be corrected but will no longer be noticed and will not be a problem, hence the term “camouflage.”

Camouflage treatment usually requires extraction of some teeth, but usually not the extraction of four first premolars, as in the treatment of crowding/protrusion.

For this boy, in whom growth modification was not successful in correcting his Class II malocclusion, extraction of upper first premolars and retraction of the upper incisors gave him both good occlusion and a normal facial appearance. If you look carefully you can see the decrease in prominence of the upper lip. He’s still skeletal Class II, but it really doesn’t show—so it’s successful camouflage.

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{{PAGE_7}} Possibilities for Treatment of Skeletal Problems: Orthognathic Surgery Treatment possibilities for skeletal problems:

1. Growth modification so the deficient jaw catches up.
2. Orthodontic camouflage.
3. Orthognathic surgery to place the jaws in the correct position. The techniques to do this were developed in the second half of the 20th century. At this point surgical correction of even extremely severe problems can be accomplished. The teaching module Indications

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{{PAGE_8}} for Orthognathic Surgery covers this in greater detail. This girl also did not respond well to growth modification treatment. Her severe mandibular deficiency is apparent. For her, retracting the upper incisors would have made her deficient lower face even more apparent and her large nose look even larger. The result would be a camouflage failure even if the malocclusion were corrected—so surgery to advance the mandible was the appropriate treatment.

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Treatment Type as a Function of Age

The type of treatment for jaw discrepancies is affected by the patient’s age.

Common sense tells you that growth modification is possible only when the patient is growing. So this type of treatment must be done prior to the end of the adolescent growth spurt. Usually, it is most effective when carried out during the growth spurt. After early adolescence, camouflage and surgery are the only possibilities. Unfortunately, growth modification does not always succeed, even if the patient cooperates.

Repositioning teeth for camouflage requires reasonably accurate prediction of growth, and the pattern of growth is notoriously unpredictable. If you aren’t sure what the final jaw relationship will be, you don’t know where to put the teeth to compensate for the jaw relationship. So camouflage should not be done until late adolescence, when it is apparent that correction via growth modification no longer is feasible and the final jaw relationship is nearly established.

Surgical correction for nearly all patients is indicated only when growth is complete or nearly complete. This means that with some exceptions for syndromic or exceptionally severe problems, surgery is not done until at or near the end of adolescent growth.

TREATMENT TIMING SKELETAL MALOCCLUSIONS

• Growth modification: Preadolescent, early adolescent
• Camouflage: Mid to late adolescent, adult
• Orthognathic surgery: Late adolescent, adult

Class II Camouflage

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{{PAGE_10}} Class II Camouflage

Class II malocclusion is the major indication for orthodontic camouflage. In Class II, the upper incisors protrude. The space to retract them is obtained by extracting the maxillary first premolars.

There are three possible extraction patterns:

• Maxillary first premolars
• Maxillary first and mandibular second premolars
• Maxillary and mandibular first premolars

Why extract in the mandibular arch if the goal is to retract the upper but not the lower incisors? It would be important not to retract the lower incisors—if that happened the overjet could not be reduced. But it also is important not to move the lower incisors more than slightly forward, because then lip pressure would cause them to relapse backward, leading to both incisor crowding and return of excessive overjet.

So extraction in the lower arch is done when Class II elastics will be used during the treatment to help reduce the overjet. These elastics, connected from the lower molars to the upper incisors, pull the upper incisors back and the lower molars forward.

In camouflage treatment when Class II elastics are planned, rather than first premolar extraction in the lower arch, second premolar extraction often is employed to guard against any retraction of the lower incisors. If the lower arch also is somewhat crowded, the combination of elastics and lower first premolar extraction might be needed to maintain the position of the incisors.

Extraction Percentages over Time

About 40% of the patients seen in a typical American orthodontic practice have Class II malocclusion. Although there have been some fluctuations in the number of patients with the extraction pattern typical for Class II (upper first premolars alone or upper first/lower second premolars), the changes are not nearly as dramatic as those for four first premolars, the typical extraction pattern for Class I crowding/protrusion.

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{{PAGE_11}} The figure shows the percentage of patients in the orthodontic clinic at UNC with extractions for Class II camouflage over a 45-year period. Although the percentage of patients with this extraction pattern was greater at the height of enthusiasm for premolar extraction in the 1960s, it did not change nearly as much as the extraction percentage for Class I crowding/protrusion patients (see To Extract or Not to Extract, part 1).

It is interesting that the percentage of Class II camouflage extractions increased somewhat in the late 1990s. This probably reflects camouflage for some patients who might have been treated better with orthognathic surgery, after denial of coverage for surgery by insurance companies.

Typical Class II Camouflage Patient

Sometimes it is thought the camouflage always is a compromise, really not the best treatment. But in the right circumstance camouflage can be very effective.

Consider Diana, who was seen initially at age 16. When asked why she had sought treatment, she just smiled (image 1)—and then explained that she tried not to smile because her teeth looked so bad. It’s a significant handicap to spend a lot of your time trying not to smile. That’s a psychosocial handicap, a good example of the reason most patients seek orthodontic treatment.

In profile (image 2), you can see that she has a weak chin, and the cephalometric radiograph (image 3) makes it clear that she has a deficient mandible. This is a skeletal Class II malocclusion, but with crowding rather than protrusion of the upper incisors—Class II division 2, in other words.

If she had been seen earlier, prior to adolescence, growth modification treatment would have been attempted, and if it had been successful, it might have been possible to treat her without extraction. At this point, the only possibilities are camouflage, which would require premolar extraction to provide space to align her upper incisors without protruding them, or surgery to advance her mandible after incisor alignment created excessive overjet.

{{PAGE_12}} Image 1, frontal view: Diana, age 16: “My teeth stick out and are crooked and ugly. Image 2, profile: Diana, age 16, profile view showing lack of projection of the mandible. Image 3, profile/ceph: The cephalometric radiograph reveals the extent of the mandibular deficiency.

Typical Class II Camouflage Patient (cont.)

Diana had the classic dental occlusion of Class II division 2, with the upper incisors crowded and upright and only mild crowding in the lower arch.

When a skeletal Class II relationship exists, the lower lip usually is behind the upper incisors, so they tip facially and overjet is present. This is the classic presentation of Class II division 1. But sometimes the lower lip remains in front of the upper incisors, which tips them lingually and leads to crowding.

It’s easier to get your lower lip in front of your upper teeth if your face height is short, so Class II division 2 patients usually have a short face and deep bite.

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{{PAGE_13}} The greater crowding in the upper than the lower arch that occurs in Class II division 2 is because the upper incisors are tipped lingually by the lower lip pressure. The upper incisors hold the lower lip away from the lower incisors, so crowding is minimized in the lower arch.

Diana: Treatment Options

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{{PAGE_14}} Diana was told that her treatment options were orthodontics alone or jaw surgery, but she also was told that for her, the orthodontic option could produce a satisfactory result. She and her family chose the orthodontic (camouflage) option.

Diana was treated with extraction of maxillary first premolars only. This meant minimal use of Class II elastics, so a transpalatal lingual arch was used to augment the resistance of upper molars to being moved forward as the extraction space was closed. The extraction space was used largely for retraction of the maxillary canines. Then the upper incisors were aligned and their roots were torqued lingually. This is a classic form of Class II camouflage.

In this cephalometric radiograph taken toward the end of treatment, you can see that overjet and overbite are now normal and the incisor roots are in a much more normal position.

Treatment Outcome: Dentition

Diana’s orthodontic treatment required 24 months. These images show her dental relationships at the completion of treatment.

Note that with upper first premolar extraction, the Class II molar relationship remains, but overjet and overbite now are normal, and the teeth are well aligned. The maxillary premolar extraction spaces were closed by distal movement of the canines.

The malocclusion has been corrected quite satisfactorily.

Is this successful camouflage treatment?

The truth is that just from looking at the dental occlusion, you don’t know.

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{{PAGE_15}} Image 1, frontal view: Diana, age 18, at completion of treatment. Image 2, right lateral: Diana, age 18, at completion of treatment. Image 3, left lateral: Diana, age 18, at completion of treatment. Image 4, maxillary occlusal: Diana, age 18, at completion of treatment. Image 5, mandibular occlusal: Diana, age 18, at completion of treatment.

Treatment Outcome: Facial Only when you look at the face can you judge the success of camouflage.

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{{PAGE_16}} Diana now enjoys displaying her smile (image 1). Successful camouflage requires two things: acceptable dental occlusion and acceptable facial esthetics. After treatment, the smile esthetics are quite acceptable, and the mandibular deficiency is hard to see (so the camouflage is successful). The post-treatment cephalometric radiograph (image 2) shows that she still is mandibular deficient, so the jaw discrepancy still is present. It’s just that at this point you don’t see it clinically (unless you have x-ray vision!). It’s easier to follow what happened in treatment by superimposing tracings of the pre- and post-treatment cephalometric radiographs (image 3). Note that, as one would have expected, she didn’t grow. The treatment change was almost totally retraction, torque, and intrusion of the upper incisors. With the amount of tooth movement that occurred in this case, it is not surprising that there was some shortening of the roots of the upper incisors (note the shortening of root length seen in the superimposition tracing). That, fortunately, is not a long-term problem, but it is necessary to warn camouflage patients that some minor root resorption, especially of the upper incisors, is likely to occur, and that there is a small chance (2-3%) of loss of more than 1/4 of the root length. Bottom line (image 4): what to the patient was an unacceptable situation now is acceptable—and that’s the definition of successful camouflage.

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{{PAGE_17}} Image 1, post-tx face: Diana, age 18, post-treatment. Smile esthetics are now quite acceptable, and the mandibular deficiency now is hard to see.

Image 2, post-tx ceph: Post-tx ceph shows that mandibular deficiency still is present.

Image 3, superimposition tracing: Superimposition tracing, pre- to post-treatment.

Image 4, smile comparison: Camouflage solved the problem of smile esthetics.

Class II Camouflage Failure

If extensive orthodontic treatment fails to camouflage the underlying jaw discrepancy, an improvement in dental occlusion isn’t much of a consolation prize.

This 18-year-old student sought further orthodontic consultation after going away to college because she was unhappy with the result of her four years of previous orthodontic treatment, first with attempted growth modification, then with extraction of upper and lower premolars. As you can see in the dental casts (image 1), the occlusion is not too bad—about 1/2 cusp Class II, with mildly excessive overjet, and if you only looked at the teeth, you might wonder what she was complaining about.

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{{PAGE_18}} It’s when you see her face (image 2) that the camouflage failure becomes apparent. She has severe mandibular deficiency. A first stage of growth modification succeeded in restricting the growth of her upper jaw but did not correct the skeletal problem, and in the attempted camouflage, her maxillary incisors were retracted much too far for acceptable esthetics.

She was told that orthognathic surgery to reposition both jaws and her chin was the only way to achieve an esthetically acceptable result. Further orthodontic treatment would be more likely to do harm than good. She had been treated for so long already, she just wasn’t willing to do that. She chose to live with what can only be described as a treatment failure.

Bottom line: If the mandibular deficiency is severe enough, camouflage simply can’t produce an acceptable result.

Image 1, dental casts: Age 18, after 4 years of orthodontic treatment, premolar extraction both arches: camouflage failure.

Image 2, facial appearance: Age 18, after 4 years of orthodontic treatment, premolar extraction both arches: camouflage failure.

Camouflage vs Surgery

Deciding Between Camouflage and Surgery

As usually is the case, there’s a gray area between patients who are clear-cut candidates for camouflage because of relatively mild problems and patients who would require surgery because of very severe problems. How does one decide between these alternatives in a borderline situation?

Consider Adam, age 18, who wants his teeth fixed. Why? Because he doesn’t like his bite and doesn’t like the way things look.

Note that he doesn’t show his teeth when he smiles. Like Diana, whom we saw earlier, he knows his dental appearance detracts, and he really tries not to show his teeth.

From the profile view, a skeletal Class II jaw relationship due to mandibular deficiency is obvious.

{{PAGE_19}} Deciding Between Camouflage and Surgery (cont.) Also like Diana, Adam has a Class II division 2 malocclusion, with crowded and irregular maxillary incisors and a deep bite. He has congenitally missing second premolars and retained second primary molars in both arches.

{{PAGE_20}} Image 1, frontal view: Adam, age 18, Class II division 2 malocclusion. Image 2, right lateral: Adam, age 18, Class II division 2 malocclusion. Image 3, left lateral: Adam, age 18, Class II division 2 malocclusion. Image 4, maxillary occlusal: Adam, age 18, Class II division 2 malocclusion. Image 5, mandibular occlusal: Adam, age 18, Class II division 2 malocclusion.

Camouflage and Surgery Possibilities

For Adam, there are two possible treatment approaches:

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1. Camouflage with extraction of second primary molars and closure of the second premolar spaces. This would be difficult because it would be necessary to retract the maxillary first premolars, then the canines, but it is feasible.

2. Orthognathic surgery, with the arches aligned without extraction in preparation for the surgery. Eventually, the second primary molars would have to be replaced, but they would be maintained as long as possible.

If you’re the doctor, how do you make the choice between the alternative treatment plans?

Adam K. — age 17-9

TREATMENT POSSIBILITIES:

1) Orthodontic camouflage

• extract maxillary primary molars, retract and intrude maxillary incisors

2) Surgical correction

• align non-extraction; mandibular ramus surgery to advance mandible and rotate chin down anteriorly

Patient, Not Doctor, Decides

The answer is very simple: In the modern world, the doctor doesn’t make that choice, the patient does! The doctor’s role is to give the patient the information needed to make an informed decision. It has been a moral imperative for a long time that alternative treatment possibilities must be presented to the patient. This now is the legal requirement in the United States, and the consequences of no treatment also must be explained.

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How does the doctor choose between the possibilities?

(S)HE DOESN’T!

In the modern world, this is the patient’s decision, not the doctor’s

• indicated morally and ethically
• now required legally in the US

Computer imaging helps the patient decide

Computer Simulations

When camouflage or orthognathic surgery are the alternative treatment possibilities, the major difference is likely to be the effect on facial proportions. This, of course, affects facial esthetics. It can be difficult for patients to understand what the difference in the esthetic outcomes might be. Computer simulations of the facial effects of treatment recently have become an important tool in helping patients decide.

It is possible now to use computer algorithms that relate the amount of change in the facial soft tissues to the amount of change in underlying hard tissues. In the absence of growth, these simulations are surprisingly accurate, good enough for patients to understand.

For Adam, as we have noted, one possibility is to correct his malocclusion by retracting his upper incisors, which would leave his facial appearance largely unchanged. The other possibility is surgical advancement of the deficient mandible, which would bring his chin down and forward and give him a “stronger” chin.

It’s one thing to tell him that. It’s something else to show him.

Here are Adam’s cephalometric tracing and soft tissue profile (image 1), and predictions of what he would look like with premolar extraction for camouflage (image 2) and with arch expansion followed by mandibular advancement (image 3). His problem is not too severe for orthodontic correction, at

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{{PAGE_23}} least as far as obtaining reasonably normal occlusion. In the prediction tracings, the dotted lines are pretreatment, solid lines are the prediction.

Image 1, pre-treatment: Adam, age 18, profile/cephalometric tracing prior to treatment.

Image 3, surgery prediction: Cephalometric/profile prediction, arch expansion, and surgical mandibular advancement.

Computer Simulations (cont.)

So looking at this image of the predictions side by side, which treatment do you think Adam would choose?

As always, the surgical treatment has the potential to make a greater difference in facial appearance, but would be more costly and would carry a greater risk. Adam and his parents would have to make their choice based on their reaction to the difference.

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{{PAGE_24}} Somewhat to the doctor’s surprise, Adam was enthusiastic about the change produced by surgery. He had given the impression that he didn’t care very much about how he looked, but both he and his parents had no problem in identifying surgery as the treatment they wanted. He went ahead with orthodontic preparation for surgery that involved aligning his upper incisors and creating overjet, to provide space for mandibular advancement, had the jaw surgery and finishing orthodontics, and was quite happy with the outcome.

But in other cases with similar changes, the reaction was, “I wouldn’t do the surgery for no more change than that.” It’s the patient’s choice. The doctor has no right to play God and make the decision for the patient.

Class III Camouflage Class III Camouflage Camouflage of skeletal Class III problems, as a rule, is less successful than Class II camouflage. The problem is that retracting the lower incisors does not make a protruding chin less prominent, and in fact may make it even more obvious.

This means two things:

1. a higher percentage of skeletal Class III than Class II patients will require surgery, and

{{PAGE_25}} 2. retracting the lower incisors a long way rarely is indicated, even if it would produce normal dental occlusion. Extracting only upper premolars to camouflage skeletal Class II often is a good idea; extracting only lower premolars to camouflage skeletal Class III usually is a bad idea. An interesting alternative for Class III camouflage patients is the extraction of one lower incisor. It seems that this would not be compatible with normal occlusion, but if the upper incisors are inclined facially and the lower incisors are upright, often good dental relationships can be obtained with three lower incisors. In fact, you should remember from the previous courses that late mandibular growth is the major cause of the mandibular incisor crowding that happens to most people in their late teens and early 20s. The more the growth pattern tends toward Class III, the greater the chance that normal alignment of the lower anterior teeth would require three (not four) incisors.

Class III Camouflage (cont.)

Consider the situation for Sally, age 13.

She had a moderately severe skeletal Class III malocclusion due to a prominent mandible (image 1), with slight reverse overjet. Mild maxillary spacing was apparent when she smiled, and lower as well as upper incisors were displayed.

Sally’s major concern, and that of her parents, was the appearance of the maxillary incisors, especially the spacing.

She was a quite mature young lady. It was unlikely that she would have a large amount of further (and disproportionate) mandibular growth. Patients of African descent often have a more prominent mandible than Europeans. For her, this was a family characteristic, but there was no history of severe Class III problems.

The teeth in both arches (image 2) were well aligned. She had spacing in the maxillary arch that reduced the tendency toward anterior crossbite, but she still had an end-to-end incisor relationship. The maxillary lateral incisors were small (these teeth are particularly likely to be missing or small in Class III patients).

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Orthodontic Treatment Plan

The plan for Sally was to remove one lower incisor and close the extraction space, which would allow moderate retraction of the remaining incisors. Then spaces could be closed in the upper arch while maintaining correct overjet and overbite. The small maxillary lateral incisors would help compensate for the potential tooth-size discrepancy created by the incisor extraction, as would the upright lower and somewhat proclined upper incisors that the jaw relationship made necessary.

Following treatment (image 1), one lower central incisor was exactly in the middle of the mandibular arch, but both overjet/overbite and occlusion of the posterior teeth were nearly ideal. The location of the maxillary dental midline is esthetically important. The location of the mandibular dental midline isn’t. Even dentists sometimes overlook a missing lower incisor unless they are careful to count the teeth—three lower incisors can look perfectly normal.

Successful camouflage? Again, you don’t know until you look at her face.

Although Sally still has a strong chin at the end of treatment (image 2), her facial appearance is within normal variation, and in fact she is quite attractive. For her, Class III camouflage was the appropriate treatment because the jaw discrepancy was mild. Premolar extraction would not have been as satisfactory as the lower incisor extraction—it would have retracted the lower incisors too much.

Image 1, post-tx teeth: Sally, age 14, retainers in place after extraction of one lower incisor and space closure in both arches.

Image 2, post-tx face: Sally, age 14, Class III camouflage.

Summary/Conclusions

Camouflage of Other Skeletal Problems

Extraction of teeth allows retraction or proclination of incisors, with the movement almost totally in the anteroposterior plane of space. For that reason, extraction is of little or no help in patients with

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vertical problems—the space is created in the wrong plane of space. This also is true for transverse skeletal problems.

So camouflage is done frequently for Class II patients, especially those who have maxillary dental protrusion and mild or moderate mandibular deficiency. It is done occasionally for Class III patients with mild skeletal problems, and rarely for those who have other types of skeletal problems.

As a treatment plan, camouflage sometimes attracts extreme opinions. It has been highly praised on some occasions as being good enough for almost all patients with skeletal problems (which we can label as the self-serving insurance company fallacy) or condemned as an old-fashioned approach to problems better treated surgically in the modern world (often offered as an excuse for never being willing to extract teeth for orthodontic purposes).

Neither of those extreme views is correct. Mild to moderate problems can be camouflaged, severe ones cannot. Who decides what is too severe for orthodontics alone? The patient, not the doctor. Appropriate patient selection, with a major role given to the patients who see computer simulations to help them decide, is the key to success with camouflage.

Problems with Camouflage

There are two major potential problems associated with camouflage:

1. Worse, not better, facial esthetics. Retracting the incisors too much can make the skeletal problem more apparent, just the opposite of camouflaging it.
2. Loss of root length (root resorption) of the maxillary incisors. This is known to occur more frequently in Class II or Class III camouflage than in other types of orthodontic treatment. It reflects the amount of tooth movement that often is required, and the chance that the roots of the teeth (especially the upper incisors) will be thrown against the cortical plates of bone.

Some dentists have been concerned that retracting the upper incisors could lead to development of TM pain/dysfunction. When it was claimed in the early 1990s that upper premolar extraction led to TMD, the rationale was that retracting the incisors led to incisal interferences and that this caused TMD.

Perhaps that is theoretically possible, although retracting the incisors enough to produce interferences would be difficult to accomplish in most Class II patients even if that were the goal. More important, clinical studies have not shown any relationship between upper premolar extraction and TMD. So TMD isn’t a complication of camouflage.

Conclusions

Camouflage of skeletal malocclusion is based on retracting protruding incisors. It usually involves retracting upper incisors in Class II patients after extraction of maxillary first premolars. Occasionally it is possible to treat mild Class III patients by retracting lower incisors after extraction of one lower incisor or second premolars.

The goals of camouflage treatment are to simultaneously obtain normal dental occlusion and normal facial soft tissue contours. The treatment can be judged as successful only if both these goals are met.

{{PAGE_28}} Camouflage rarely is adequate treatment for patients with severe jaw discrepancies. The alternative, orthognathic surgery, must be considered for these patients.

The patient must be involved in the decision for camouflage versus orthognathic surgery. Computer simulations of possible treatment outcomes are a valuable tool in providing information to help patients decide what treatment they want, especially in borderline situations when both camouflage and surgery are reasonable alternatives.

Possible complications of camouflage include unfortunate facial esthetic changes and root resorption of upper incisors, but the evidence shows that despite claims to the contrary, it does not lead to the development of TMD.

Self-Test Referral

The self-test section of this program is designed to help you be sure you have understood the material. Read the assigned material in Contemporary Orthodontics, (5th ed., pp ; 4th ed., pp. ), then take the test, and use it as a guide for further study and review.

Copyright 2013, UNC Dept. of Orthodontics

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{{PAGE_29}} 2. Special Considerations in Orthodontics for Adults

Demand for Treatment / Motivation

Demand for Adult Treatment

Adult orthodontics was quite rare in the United States until the 1970s, then became the fastest growing area in orthodontics (image 1). By 1990, 25% of all patients receiving comprehensive treatment were age 19 or older.

Since then, the number of adult patients in the United States has remained relatively constant, but the proportion of adults has dropped to 20% because of growth in the number of children receiving treatment (image 2). For more than two decades now, adults with fixed braces on their teeth have been commonly observed at all levels of American society.

The same trend toward more adult orthodontics occurred somewhat later in Western Europe and Japan, where adult orthodontics now frequently is done. It is happening now in other countries as economic advances occur, for example, in the Eastern European countries formerly behind the Iron Curtain.

Having braces on their teeth is no longer a social problem for most adults. Increasingly, this is accepted as nothing special or even a sign of upward social mobility.

Motivation for Treatment: Improve Present Situation

Adult orthodontic patients can be placed into two groups: those whose motivation is to improve their present situation, and those whose goal is to keep what they have.

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{{PAGE_30}} Special Considerations in Adult Orthodontics

• Changes in demand for treatment
• Motivation for treatment

Group 1, Goal: improve present situation (often, motivation is psychosocial)

Image 1, motivation

Special Considerations in Adult Orthodontics

• Changes in demand for treatment
• Motivation for treatment

• Group 1: younger group, seek comprehensive treatment, often want ceramic brackets / lingual orthodontics, perhaps “invisible braces”

Hidden agenda?

Image 2, treatment desired

Motivation for Treatment: Maintaining Present Situation In contrast, the motivation for a second group of adults is not to improve their present situation, but to keep it from getting worse—their goal is to maintain what they have (image 1). The threat typically is loss of teeth and the facial soft tissue/dental appearance changes that accompany tooth loss and aging. These adults tend to be older (usually age 35 and up, but sometimes younger). Their motivation makes them candidates for treatment involving multiple types of dentistry (image 2). Typically, treatment of periodontal problems and restoration of damaged/missing teeth is required, and the goal of orthodontic treatment is to facilitate the other treatment that the patient needs, not to comprehensively make occlusion and alignment as ideal as possible. The appearance of the orthodontic appliance often is only a minor concern. Recent experience makes it clear that including orthodontics in the treatment plan for such patients can produce better results than otherwise would have been possible, and in the last decade this has

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{{PAGE_31}} been the fastest growing area in orthodontic treatment. The average age of adult orthodontic patients has increased.

Special Considerations in Adult Orthodontics • Changes in demand for treatment • Motivation for treatment Group 1: seek to improve present situation Group 2: seek to keep what they have (motivation relates to disease control)	Special Considerations in Adult Orthodontics • Changes in demand for treatment • Motivation for treatment - Younger group: comprehensive treatment, ceramic brackets / lingual orthodontics, etc. - Group 2: older, seek adjunctive treatment, interdisciplinary considerations important The fastest-growing area in orthodontics
Image 1, motivation	Image 2, treatment desired

Periodontal Considerations

Periodontal Problems by Age

A third important area, which requires even greater emphasis in orthodontics for adults than it does in children, is the health of the periodontium. Several health-related considerations are important.

First (image 1), let’s review the prevalence of periodontitis/periodontal pockets and mucogingival problems (lack of adequate attached tissue) at various ages.

The graph in image 2 is derived from examination of 1000 patients with severe malocclusion who were evaluated through UNC’s Dentofacial Clinic for possible orthognathic surgery.

Note that the prevalence of periodontal pocketing, reflecting bone loss, doubles between age 20 and 26 and doubles again by age 33-39. The odds are that potential orthodontic patients who are over age 30 will have some evidence of periodontal disease. The severity of malocclusion is not a major factor in whether periodontal problems develop, so these prevalence numbers are reasonable estimates for adult orthodontic patients with less severe problems.

Note also that mucogingival problems, typically a lack of attached gingiva, are much more prevalent than pocketing in the 10-19 age group who are the more frequent candidates for orthodontics—but this peaks in the early 20s and actually declines thereafter.

The bottom line: It’s critically important to be sure that periodontal disease is under control before any orthodontics begins—and periodontal problems, though perhaps of different types, are likely to be present in both younger and older adults.

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{{PAGE_32}} Special Considerations in Adult Orthodontics

• Changes in demand for treatment
• Motivation for treatment
• Periodontal considerations
  • prevalence of periodontal conditions
    • periodontitis / pocketing
    • mucogingival problems: inadequate attached tissue

Detection of Periodontal Problems

A second important aspect of periodontal health in adults who are candidates for orthodontic treatment is the detection of periodontal problems (image 1).

The guideline for any sort of orthodontics is simple: Orthodontic treatment is quite feasible for patients who have had periodontal disease and bone loss—but tooth movement cannot begin until active disease is brought under control.

Of course the best indicator of active disease is bleeding on gentle probing (image 2).

It is equally important to remember that expansion of the dental arches stresses the gingival attachment and can lead to further loss of gingival tissue. The primary trouble area is the lower incisor region, where alignment of crowded incisors tends to move them facially (image 3). Arch expansion in other areas, however, also stresses the gingival attachment.

Tooth movement that stresses the attachment is risky in children who do not have good gingival attachment before treatment starts—and it’s even riskier in adults. Areas of reduced attachment must be evaluated carefully when tooth movement is planned.

Measuring the amount of attached tissue, and noting areas that already are at risk, are important steps in detecting potential mucogingival problems. Repositioning frenum attachments and/or placing a gingival graft before orthodontics begins may be needed.

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Special Considerations in Adult Orthodontics

• Changes in demand for treatment
• Motivation for treatment
• Periodontal considerations
  • prevalence of periodontal conditions
  • detection of problems

Image 1, outline

Bleeding on gentle probing:

the best indicator of active periodontal disease

It’s not really the pocket depth that’s important, it’s whether active disease is present

Image 2, active disease

Lack of attached gingiva: likely to complicate orthodontics

Advancing crowded lower incisors to align them risks stripping gingiva and exposing roots if the gingival attachment is inadequate

Even riskier in adults!

Image 3, mucogingival

Orthodontics and Periodontal Health (cont.)

A third important periodontal consideration in adult orthodontics is the effect of bone loss on the amount of force for orthodontic tooth movement (image 1). If bone loss has occurred in an adult patient, both the amount of force and the magnitude of the moment to control root position must be adjusted.

By now you are quite familiar with the optimal force for various types of tooth movement, as shown in image 2. Remember that there is only one optimal pressure in the PDL. The amount of force for the various tooth movements varies because the force distribution in the PDL varies, hence the force variation keeps the pressure at the optimum.

But these forces are based on the assumption that the amount of periodontal ligament area is normal, i.e., that the amount of root supported by alveolar bone is normal.

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{{PAGE_34}} Special Considerations in Adult Orthodontics

• Changes in demand for treatment
• Motivation for treatment
• Periodontal considerations
  • prevalence of periodontal conditions
  • detection of problems
  • effect of periodontal bone loss on orthodontic force

Optimum Force for Orthodontic Tooth Movement grams Tipping 50 Bodily mvt. 100 Rotation 50 Torque 75 Extrusion 50 Intrusion 10 (IF the amount of root in bone is normal!) There’s one optimal pressure in the periodontal ligament

Image 1, outline Image 2, orthodontic force

Effect of Bone Loss on Orthodontic Force (cont.) Consider the force system to move a premolar bodily (image 1). For bodily movement, a force of 100 grams is appropriate. If this force is applied against the crown, however, the tooth will tip, because force against the crown is at a distance from the center of resistance, which is about the midpoint of the part of the root supported by bone. Typically, that distance is about 10 mm, so a 100-gm force against the crown creates a 1000 gm-mm moment (moment of the force, MF). To obtain bodily movement, a moment in the opposite direction with a magnitude of 1000 gm-mm must be created, by applying a couple on the bracket (moment of the couple, MC).

Now look at the situation when significant bone loss has occurred (image 2). If the bone level is halfway down the root, the area of the periodontal ligament over which the force will be expressed is half what it would be normally, so now 100 grams would produce twice the optimal pressure. Further, the center of resistance now would be 15 mm from the bracket, not 10, so the moment of the force would be 1500 gm-mm, and a 1000 gm-mm moment from the couple on the bracket would not be enough to prevent tipping.

For bodily movement of a premolar with loss of half the alveolar bone, the optimal force would be 50 gm, not 100 gm (image 3). Since the moment of this force would be 750 gm-mm (50 gm x 15 mm to the center of resistance), the moment of the couple on the bracket would have to be 750 gm-mm. The force was reduced by half, but the moment of the couple only decreased 25%.

You might have thought that since adults have harder heads, it would take more force to move their teeth. It’s just the opposite. Successful tooth movement in adults, especially those who have had bone loss, requires careful use of light forces and relatively larger moments to control root position.

{{PAGE_35}} Effect of bone loss on pressure in the PDL from orthodontic force To move a normal premolar bodily:

• 100 gm force produces optimal pressure (x) in PDL
• 1000 gm-mm moment produces root movement

Image 1, normal

Effect of bone loss on pressure in the PDL from orthodontic force With loss of supporting bone and same force:

• PDL volume is smaller, so pressure in PDL is too large
• distance to CR is larger, so MCOR is too small and the tooth tips

Image 2, bone loss

So a patient with bone loss requires:

• decreased ortho force, to maintain optimal pressure in PDL
• increased moment, to control root position

Image 3, corrected for bone loss

Patient Management Patient Management As people get older, lots of things aren’t as easy as they once were. Tolerating orthodontic treatment definitely falls into that category (image 1). If you’re the family dentist and one of your adult patients has orthodontic treatment, you’re very likely to hear about how difficult it was to get through the first couple of weeks. Don’t tell adults, “Oh, there’s nothing to it really—you’ll do just fine.” Tell them there will be all kinds of things that are problems during those first 2 weeks, but fortunately after that it gets better. Expectations affect the reaction to most treatment. Often it’s not so much that things are good or bad that determines your reaction, it’s the extent to which the reality matches what you expected. It’s important to provide medication for pain control (image 2). Adults have sore teeth initially to an extent that children don’t, and also are more likely to complain about mucosal lesions where some

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{{PAGE_36}} part of the appliance touches the lips or cheek.

Reminding patients to keep wax on any irritating part of the appliance until they get used to it, and giving them a small tube of a topical anesthetic, can prevent “emergency” appointments during those first 2 weeks.

Ibuprofen, on balance, probably is the best choice for pain control. The new COX-2 inhibitors have the potential advantage for adults that they reduce stomach irritation and require only one tablet per day, but their safety still is questionable for long-term use and at present their cost is considerably higher.

Reassurance and Explanation

Finally, children and adolescents often are somewhat indifferent about their orthodontic treatment. That doesn’t happen with adults. They’re intensely interested, and the clinician has to be prepared for questions and discussion about how the treatment is going.

As one adult orthodontic patient put it, “You might as well go ahead and tell me all about it while you’re doing the treatment, because if you don’t I’m going to ask you before I leave.”

What has happened since last time? How am I doing? What are you doing today? Why? What’s going to happen between now and next time? Will I have any special difficulty?

If you’re the family dentist and your patient now is seeing an orthodontist, be prepared. The patient is going to tell you all about it, ask if you think things are going well, and seek your opinion about whether the orthodontist will finish the treatment on time.

It’s just part of patient management—easier to handle if you expect it.

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{{PAGE_37}} Patient management considerations

• Remember that adults often have difficulty in adapting to treatment
• Provide medication for pain control
• Expect additional chair time for explanation and reassurance

Tell me:

• what happened since last time
• what you’re doing, and why
• what’s going to happen now

Case #1: Incisor Intrusion / Build-Ups

Case #1: Incisor Intrusion, Incisor Build-Ups Now let’s consider three patients who illustrate specific areas of interest for adult orthodontics, beginning with a young adult who needs intrusion of maxillary incisors and build-ups for small incisors.

Steve’s chief complaint (image 1) was the appearance of his upper incisors. He said, “I try never to smile showing my front teeth.” After graduation from college, he was working as a research technician in the orthodontic department and became aware that this could be corrected.

Facial proportions generally were normal (images 2 and 3), but note that there is a mild mandibular asymmetry, with the chin off to the left. This isn’t a problem, but it is something that should be observed. It explains why the dental midline also is slightly off in the same direction.

{{PAGE_38}} Image 1, smile: Steve, age 22, prior to treatment. Image 2, frontal: Steve, age 22, prior to treatment.

{{PAGE_39}} Case #1: Initial Records

In the frontal view of the dentition (image 1), note the elongation of the maxillary central incisors, deep overbite, and incisor spacing.

The molar relationship is normal (Class I), but the maxillary incisors are very upright, almost in a Class II, division 2 pattern (images 2 and 3).

The upper and lower teeth are well aligned (images 4 and 5), but spacing around the small maxillary incisors is apparent. Tooth size analysis confirmed that both the maxillary central and lateral incisors were small relative to the other teeth.

{{PAGE_40}} Image 1, frontal view: Steve, age 22, prior to treatment. Image 2, right lateral: Steve, age 22, prior to treatment. Image 3, left lateral: Steve, age 22, prior to treatment. Image 4, maxillary occlusal: Steve, age 22, prior to treatment. Image 5, mandibular occlusal: Steve, age 22, prior to treatment.

Case #1: Initial Records On the panoramic radiograph (image 1), it is apparent that the dentition is generally healthy, with no restorations and no evidence of alveolar bone loss. Note the elongated maxillary left third molar. A tooth in this position can be the cause of a mandibular shift on closure. As a general rule, removal of third molars is indicated before comprehensive orthodontics for adults begins.

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{{PAGE_41}} The cephalometric radiograph and tracing (images 2 and 3) confirm the upright/elongated position of the maxillary central incisors. The anteroposterior jaw relationships are normal, and lower face height is slightly decreased.

{{PAGE_42}} Image 1, pan: Steve, age 22. Note the elongated maxillary 3rd molar. Image 2, ceph: Normal jaw relationships, upright/elongated maxillary incisors. Image 3, tracing: Normal jaw relationships, upright/elongated maxillary incisors.

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{{PAGE_43}} Case #1: Treatment Plan

The plan for Steve was to address his primary problem of elongated/spaced maxillary incisors and excessive overbite, using segmented arch mechanics to intrude the central incisors (this is the only way to obtain the very light force necessary for intrusion), then build-ups of the small incisors with composite resin to bring them to normal size and eliminate spacing.

The first step in treatment would be to remove the elongated maxillary left third molar. A tooth in this position creates a potential occlusal interference, and even if it is tolerated prior to treatment, it can become a problem during treatment.

When arch segments are created, and especially when intrusion of maxillary incisors is desired, a transpalatal lingual arch becomes an important stabilizing/anchorage part of the orthodontic appliance.

Because of the deep bite anteriorly, it would not be possible to place brackets on the lower incisors until the upper incisors had been repositioned, so treatment for the upper arch would have to start first.

Case #1: Incisor Intrusion

The first step in the orthodontic treatment was to align the teeth within segments. In this case, the two central incisors were one segment, and the molar-lateral incisor portions of the arch on either side were separate segments.

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{{PAGE_44}} Intrusion of upper incisors requires a lingual arch. At the first appointment, mandibular and maxillary molar bands were fitted, and the upper molar bands were sent to the lab for fabrication of the lingual arch. These bands and the lingual arch were placed at the next appointment.

A continuous arch wire must not be used when the goal is intrusion. Such arch wires always are extrusive, not intrusive, because when steps are placed in the arch wire to change the vertical relationship of brackets, the force is far above the amount needed for intrusion. The relationship of the teeth changes, but the tooth movement is extrusion of the presumed anchor teeth, not intrusion of the ones where this was desired.

Case #1: Incisor Intrusion (cont.)

After initial alignment, an intrusion arch was used, first to deliver a precisely measured 20 grams (10 grams/tooth) to the maxillary central incisors. Intrusion requires light force to obtain the optimal pressure in the small PDL area around the apex of the tooth. If the force is too heavy, cells in the periapical area of the PDL become necrotic, recruitment of osteoclasts is slow, and the bone remodeling necessary for intrusion does not occur.

The intrusion arch fits into auxiliary rectangular tubes on the first molar bands and is tied to the wire segment in the incisor segment. The position of the intrusion arch in the anterior vestibule (images 1

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{{PAGE_45}} and 2) is adjusted until bending it downward to the level of the teeth produces 20 gm force (images 3 and 4). A force gauge is used to measure the force created by deflecting the wire. Intrusion of maxillary incisors requires the use of a transpalatal lingual arch to control the position of the upper molars (image 5). Note that in this case, the intrusion arch is tied in the midline (image 3). The point of attachment of the intrusion arch to the segment wire can be varied, depending on what change in tooth position in addition to intrusion is desired.

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{{PAGE_47}} Tying an intrusion arch in the midline places the point of force application anterior to the center of resistance of the incisors, so they would tip facially as they intrude unless the intrusion arch were tied back against the molars to prevent this. In Steve’s case, facial movement of the incisors was desired, so the intrusion arch was left free to slip forward as the teeth responded to the force system.

This tooth movement allowed enough space to place brackets on the lower arch without occlusal interferences, and treatment for the lower arch began soon thereafter.

Case #1: Extrusive Leveling, Lower Arch

Later in treatment, leveling of the lower arch was needed to complete correction of the deep overbite. Because a slight increase in face height was desired, this was done with a continuous arch wire and an auxiliary leveling arch that delivered 150 grams, so that the lower molars would be extruded.

An important concept: Intrusion of incisors requires the use of segmented arch wires and light force. Continuous arch wires and heavier force produce extrusion of posterior teeth, not intrusion of incisors.

Steve had intrusive mechanics in the upper arch, extrusive mechanics in the lower arch. The important differences:

{{PAGE_48}} Arch wire segments tied into the brackets in the upper arch, continuous arch wire tied into the brackets in the lower arch Light (20 gm) force from the auxiliary wire in the upper arch, heavier (150 gm) force from the auxiliary wire in the lower arch Image 1, not activated: Auxiliary leveling arch, not activated. Image 2, activated: Auxiliary leveling arch, activated by tying to main arch wire. Case #1: Maxillary Incisor Torque/Spacing Then active torque was placed in a rectangular maxillary arch wire to bring the roots of the incisors to the lingual, and space was distributed around the upper incisors to allow build-up of these teeth to normal size (images 1-3). Note that space between the maxillary incisors is being adjusted by coil springs that were slipped over the arch wire before it was inserted. A cephalometric radiograph near the end of treatment (image 4) shows the change in incisor position, and the cephalometric superimposition (image 5) documents both intrusion and torque of the maxillary central incisors. The lower incisors were tipped facially slightly as the lower arch was leveled. Now he is ready for the incisor build-ups, which must be coordinated with the completion of the orthodontic treatment.

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{{PAGE_49}} Image 1, frontal view: Progress: rectangular arch wire for torque, coil springs to adjust incisor position. Image 2, right lateral: Progress: rectangular arch wire for torque, coil springs to adjust incisor position. Image 3, right lateral: Progress: rectangular arch wire for torque, coil springs to adjust incisor position. Image 4, ceph: Cephalometric radiograph near end of treatment.

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{{PAGE_50}}

Case #1: Incisor Build-Ups

In order to allow the best restorative dentistry, the orthodontist provides slightly excessive space before incisor build-ups are done. The ideal sequence is:

• the brackets are removed from the upper incisors,
• the patient goes immediately to the restorative dentist, and
• the brackets are reapplied after the restorations are completed, so that the excess space can be closed with complete control of tooth positions.

A less satisfactory alternative is to position the teeth to be built up as precisely as possible as the orthodontic treatment is completed and provide a retainer until the restorations are completed. Any excess space then would have to be closed with a modified retainer—which is possible but more difficult and less precise.

Steve’s maxillary incisor brackets were removed early in the morning, the restorations were done the same morning (by Dr. Harald Heymann), and the brackets were replaced that afternoon so that closure of the remaining space could begin.

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{{PAGE_51}} Image 1, pre-buildup: 9 AM, just prior to removal of the arch wire and incisor brackets. Image 2, buildups completed: 1:30 PM same day, back to orthodontist after build-ups. Image 3, continuation: 2 PM same day, brackets and arch wire replaced.

Case #1: Incisor Build-Ups (cont.)

Image 1 shows the appearance of the teeth at 1:30 PM, after completion of the restorations, just before the brackets and arch wire were replaced.

Note that as planned, there is still some space in the incisor segment. The last step in the orthodontics is final space closure and positioning of the teeth.

Image 2 shows the appearance of the teeth at 2 PM the same afternoon, with brackets reapplied, the arch wire replaced, and the appliance activated for closure of the residual space.

Close coordination of the restorative and orthodontic treatment at this stage is important for best results. Any delay between removal of the arch wire and brackets and the build-ups is an opportunity for uncontrolled shifting of the teeth, which can compromise the quality of the restorations. A delay in reapplying the orthodontic appliance is not as critical, but orthodontic finishing should proceed as rapidly as possible.

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{{PAGE_52}} Image 1, build-ups: After completion of build-ups, before the arch wire and brackets were replaced. Image 2, treatment continuation: Same day, continuation of orthodontics.

Case #1: Treatment Completed

Images 1-3 show the appearance of the dentition at the removal of the orthodontic appliance five months later. After completion of the incisor build-ups, the residual spaces were closed and the teeth were put into their final position.

When a space between maxillary central incisors has been closed, long-term retention usually is needed. Like most adults, Steve did not like wearing a removable retainer that covered the palate. Children tolerate these much better than adults.

A fixed retainer, contoured to allow easy flossing and with vertical stops to control overbite, was used instead (image 4). After correction of excessive overbite, the retainer must maintain the correct bite depth as well as alignment. It would be expected to remain in place at least for a time equal to the duration of active treatment.

{{PAGE_53}}

Case #1: Treatment Completed

Facial proportions were essentially unchanged during the nearly 2 years of treatment (image 1). The mild mandibular asymmetry was not corrected, because it was not a problem to the patient, and indeed is noticed only on careful examination.

A comparison of the smile appearance before and after treatment (image 2) shows the esthetic effect of this combination of orthodontic and restorative treatment.

Cephalometric radiographs before and after treatment (image 3) show the changes in incisor position and overbite that were obtained. Note that the roots of the maxillary incisors were torqued lingually, improving the inclination of these teeth.

The effect of this tooth movement on the position of the teeth can be seen in the comparison views of before and after treatment (images 4 and 5).

Total treatment time was just over 2 years.

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{{PAGE_54}} Image 1, post-tx face: Posttreatment facial proportions. Image 2, smile comparison: Smile comparisons pre- to posttreatment. Image 3, cephalometrics: Pre- and posttreatment cephalometric radiographs. Image 4, frontal change: Pre- and posttreatment occlusion, frontal view. Image 5, lateral change: Pre- and posttreatment occlusion, lateral view.

Case #2: Severe Perio / Fiber Section

Case #2: Severe Perio/Fiber Section Surgery

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{{PAGE_55}} Now let’s look at a second case, a young adult whose main reason for treatment was the control of severe periodontal problems and who had an adjunctive periodontal surgical procedure to facilitate orthodontic retention.

Nancy was only in her 20s when she developed severe periodontal disease. After treatment brought the disease under control, she was referred for orthodontics by her periodontist, who felt that maintaining control would be more likely if her severe crowding were corrected.

Nancy would not have sought orthodontic treatment otherwise, but said she would appreciate the dental esthetic improvement from aligning her upper incisors, which detracted from her smile (image 2). On profile examination, no disproportions were apparent (images 3, 4).

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{{PAGE_56}} Special Considerations In Adult Orthodontics

• Changes in demand for treatment
• Motivation for treatment
• Periodontal considerations
• Treatment situations
  • Case #2, Early / severe perio; fiber section surgery

Image 1, outline

Image 2, frontal view: Irregular maxillary incisors were apparent on smile.

Image 3, profile: Normal jaw proportions are seen in the profile view.

Image 4, combined: Esthetics: a consideration but not the main reason for treatment.

Case #2: Initial Records Although her molar relationship was Class II bilaterally, Nancy had minimal overjet with severe crowding and rotation of the maxillary incisors. There was only moderate crowding in the lower arch. The upper lateral incisors were very large, and the central incisors were each rotated 45 degrees. The severe crowding in the maxillary arch, therefore, had two causes: (1) the Class II molar relationship

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{{PAGE_57}} with minimal overjet, and (2) the tooth-size discrepancy created by the large lateral incisors.

{{PAGE_58}} Case #2: Initial Records (cont.)

The intraoral radiographs (image 1) showed the extent of bone loss in multiple areas. Note particularly the extensive pocketing on the distal of the upper right 2nd premolar.

A major indication for a full series of periapical radiographs is the presence of widespread periodontal disease. For a patient like Nancy, a panoramic radiograph prior to orthodontic treatment is not sufficient. Detailed images of areas with potential disease are necessary.

The cephalometric radiograph and tracing (image 2) confirmed a dental but not a skeletal Class II malocclusion, i.e., the Class II molar relationship was due to a forward position of the upper molars.

For an adult patient, cephalometric analysis has two purposes: (1) to allow a more refined diagnosis (for example, in Nancy’s case, so that the cause of the Class II malocclusion could be described more precisely), and (2) to make it possible to use superimposition tracings to follow the course of treatment.

The second reason is the compelling one for cephalometric radiology in most orthodontic treatment. You often can make the diagnosis accurately enough for appropriate treatment planning without cephalometric analysis, but it is impossible to know exactly what is happening in treatment without serial radiographs that can be superimposed.

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{{PAGE_59}} Image 1, intraoral radiographs: Nancy, age 27, intraoral radiographs. Image 2, ceph: Nancy, age 27, cephalometric radiograph. Image 3, ceph tracing: Nancy, age 27, dental but not skeletal Class II.

Case #2: Treatment Plan

The treatment plan for Nancy emphasized continued treatment to keep periodontal disease under control. A patient like this who has orthodontic treatment needs frequent recall for periodontal maintenance, perhaps as frequently as she sees the orthodontist, certainly at not more than 2-3-month intervals.

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{{PAGE_60}} The plan was to extract the maxillary right 1st premolar and the maxillary left 2nd premolar, which was selected for extraction because of its poor periodontal prognosis (see the intraoral radiographs, previous screen) even though the orthodontic treatment would have been easier if both first premolars could have been removed. Because of the limited posterior anchorage, a maxillary transpalatal arch to stabilize the position of the upper molars was planned, and the canines were to be retracted separately before the incisors were aligned, which would also reduce the strain on the posterior teeth. Gingival surgery to section the gingival elastic fibers was planned because it would be critically important in maintaining the rotation correction for the maxillary central incisors. The fiber section procedure is most effective if it is done after the teeth are in their final position (i.e., rotations have been corrected) but before the orthodontic appliance is removed, so that the teeth can be held in position while healing occurs.

Case #2: Progress, 18 Months Treatment

After 18 months, the maxillary incisors had been aligned and the extraction spaces were closed. The improved alignment was apparent on smile (image 1). On the maxillary occlusal view, note that the transpalatal lingual arch has been removed after completion of closure of the extraction space. The large maxillary lateral incisors were reduced in width as much as feasible without going all the way through the proximal enamel (image 2), and the mild mandibular incisor crowding was corrected by slight expansion of the arch (image 3).

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{{PAGE_61}} At this point (image 4), she was ready for the fiber section surgery, to release the tension in the gingival elastic fibers created by correcting the rotation of the incisors.

Image 1, progress smile: Nancy, age 28, after incisor alignment and space closure in the upper arch.

Image 2, maxillary occlusal: Incisor alignment and space closure in the upper arch.

Image 3, mandibular occlusal: Nonextraction alignment of lower arch.

Image 4, frontal: Progress, ready for fiber section surgery.

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{{PAGE_62}} Case #2: Fiber Section Surgery With the orthodontic appliance in place, the periodontist (Dr. Ray Williams) carried out the gingival surgery.

The first step was facial (image 1) and lingual (image 2) incisions within the gingival sulcus to section gingival fibers and allow repositioning of the frenum.

Then the gingival papillae were sectioned almost but not quite to the tip (image 3) and sutured into position (image 4), to minimize shrinkage of the papillae during healing.

Two weeks later, healing was essentially complete (image 5).

{{PAGE_63}} Image 1, facial incisions: Facial incisions, for repositioning of the frenum. Image 2, lingual incisions: Lingual incisions to base of gingival sulcus. Image 3, papilla split: Incisions in gingival papillae to section gingival elastic fibers. Image 4, papillae sutured: Papillae sutured after incisions. Image 5, healing at 2 weeks: Healing at 2 weeks.

Case #2: Completion of Treatment Treatment was completed and orthodontic appliances were removed at 24 months. Periodontal control had been maintained successfully, and the fiber section procedure also succeeded in maintaining papilla height, which is important in esthetically sensitive areas like the maxillary incisor region. She liked the change in her dental and facial appearance (images 1, 2). The change in smile esthetics was particularly pleasing (image 3).

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{{PAGE_64}} The maxillary premolar extraction spaces were closed largely by retraction of the canines, so that the Class II molar relationship was maintained and overjet did not develop (image 4). Note the improved contours and color of the gingiva, reflecting an improvement in periodontal health even though significant bone loss still is present.

At this point the teeth were well aligned in both arches, but retention would be important. In patients who have had bone loss, deep undercuts around the teeth make palate-covering retainers impractical. Like most adult patients, Nancy had thermoplastic suckdown retainers for both arches, made with undercuts waxed out. These were worn full-time initially, then on a decreasing part-time basis after the first 4 months.

Image 1, post-tx frontal: Nancy, age 29, at completion of treatment. Image 2, post-tx profile: Nancy, age 29, at completion of treatment. Image 3, smile comparison: Smile before and after treatment. Image 4, dental relationships: Dental relationships after treatment.

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{{PAGE_65}}

Case #2: Completion of Treatment (cont.)

In the posttreatment panoramic radiograph (image 1), areas of bone loss related to the original periodontal disease can be seen, but there has been no progression during the orthodontic treatment, and some improvement can be observed especially in the maxillary right premolar area.

Comparison with the pretreatment radiographs (image 2) shows that extraction of the maxillary right 2nd premolar and closure of the extraction space eliminated one of the worst periodontal defects. Note the bone fill-in in the old 2nd premolar extraction site.

Fortunate results of this type can occur if the area of a periodontal defect is curetted regularly as the orthodontics proceeds, but cannot be expected routinely. On the other hand, with good periodontal maintenance, the periodontal condition should not become worse during even extensive orthodontic treatment.

Case #2: Two-Year Recall

On 2-year recall, Nancy was wearing retainers only at night, and her periodontal condition was being maintained quite nicely. Her smile esthetics remained good (image 1).

The alignment and occlusion of the teeth were well maintained after 2 years (image 2). Although she admitted that her retainer wear had become sporadic after the first year, the severely rotated maxillary incisors were still well aligned.

Almost surely, that would not have been the case without the fiber section surgery. Sectioning stretched gingival fibers after rotated teeth have been corrected is critically important for long-term retention. Teeth that have been severely rotated, like Nancy’s upper central and lateral incisors, simply will not stay aligned without surgical release of the pull of gingival elastic fibers.

In this case, perio surgery was needed not only before orthodontics to help bring disease under control but also as an adjunct to successful orthodontics.

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{{PAGE_66}} Given the severity of bone loss in several areas, Nancy will need to be followed carefully long term— but her periodontal prognosis is significantly better after the orthodontics.

Image 1, 2 year facial: Nancy, age 31, 2-year recall. Image 2, 2 year dental: Nancy, age 31, 2-year recall.

Case #3: Adjunctive Cosmetic Surgery

Case #3: Adjunctive Cosmetic Surgery

Now let’s look at a third adult patient, for whom adjunctive facial cosmetic surgery was an important part of the treatment plan.

Ronald (image 2) inquired at age 48 about the possibility of cosmetic bonding of his incisor teeth to improve their appearance. His motivation definitely was to improve his facial and dental appearance—and though it was not said in so many words, to improve his social image and interactions.

His mustache took attention away from what in novels often is described as a “weak chin.” He had poor throat form, with a quite obtuse lip-chin-throat angle (the ideal is near 90 degrees) and minimal throat length.

His chief concern was the appearance of his maxillary incisors (image 3). The left lateral incisor was congenitally missing, and the midline was shifted severely to that side.

Despite the missing maxillary lateral incisor, the maxillary incisors were crowded and malaligned. There was severe crowding in the mandibular arch, with a malformed mandibular right second molar (image 4).

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{{PAGE_67}} Special Considerations In Adult Orthodontics

• Changes in demand for treatment
• Motivation for treatment
• Periodontal considerations
• Treatment situations
  • Case #3, Orthodontics / Adjunctive Cosmetic Surgery

Image 1, outline

Image 2, pre-tx face: Ronald, age 48, prior to treatment.

Image 3, front teeth: Maxillary incisor crowding, left lateral incisor missing, midline off.

Image 4, occlusal views: Moderate maxillary, severe mandibular crowding.

Case #3: Initial Records

His periodontal condition generally was good, except for bone loss and pocketing on the distal of the mandibular right second molar, where a partially impacted third molar still was present (image 1). Current research has shown that the chance of periodontal breakdown adjacent to a third molar in this position is quite high. A partially erupted mandibular third molar is a greater risk for long-term problems than a completely impacted one.

Multiple restorations were present, and the mandibular left second premolar had a root canal filling. An endo-treated tooth can be moved, but its poorer long-term prognosis must be considered in treatment planning.

Cephalometric analysis (image 2) showed a skeletal Class II jaw relationship, with chin deficiency and somewhat increased face height. The relationship of the upper incisors to the maxilla is

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{{PAGE_68}} reasonably normal; the lower incisors are severely protrusive relative to the deficient chin. For this reason, overjet was normal. The rotation of the palatal plane (which should be tipped in the other direction, intermediate between the occlusal plane below and true horizontal line above) indicates a skeletal open bite tendency.

Image 1, panoramic radiograph: Note the periodontal problem area distal to the mandibular right second molar.

Image 2, ceph/tracing: Chin deficiency, prominent lower incisors, rotated palatal plane.

Case #3: Treatment Plan

Aligning the maxillary incisors and correcting the midline would require space to bring the central incisors around to the right, and extracting the right lateral incisor would allow the greatest improvement in the midline. The major esthetic problem with using canines to replace missing lateral incisors is their greater crown height, but Ronald’s low lip line meant that the gingival margins were not visible even on smile, and the cusp tips could be reshaped. The decision, therefore, was to extract the right maxillary lateral incisor and substitute the canines for the laterals.

The goal in the lower arch was to align the teeth without retracting the lower incisors, which would create excessive overjet, so extraction of mandibular second premolars was chosen. Extraction of the remaining third molar was an important aspect of bringing periodontal disease under control.

Because of the deficient chin and poor throat form, a lower border osteotomy of the mandible to bring the chin forward (a type of genioplasty) was suggested. He agreed to consider this as the orthodontic treatment came to a close.

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{{PAGE_69}}

Ronald S. — age 48

Plan:

• extract maxillary left lateral incisor, mand R & L 2nd premolars, R 3rd molar
• align teeth without retracting mandibular incisors
• lower border osteotomy of the mandible to move the chin upward and forward
• prolonged retention

Case #3: Progress

After 16 months of orthodontic treatment, the teeth were aligned. In the maxillary arch, there was still a small amount of space to bring the maxillary central incisors around to the right to improve the midline discrepancy, and the mandibular second premolar extraction sites were not quite closed. The cusp tips of the maxillary canines had not yet been flattened to make them look more like lateral incisors.

Ceramic brackets were used on the maxillary incisors to reduce the esthetic impact of the orthodontic appliance. Although these brackets are more esthetic, they make treatment more difficult, and their use is limited to highly visible teeth only.

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{{PAGE_70}} Image 1, frontal view: Age 49, 16 months progress, teeth aligned, space nearly closed. Image 2, right lateral: Age 49, 16 months progress, teeth aligned, space nearly closed. Image 3, left lateral: Age 49, 16 months progress, teeth aligned, space nearly closed. Image 4, maxillary occlusal: Age 49, 16 months progress, teeth aligned, space nearly closed. Image 5, mandibular occlusal: Age 49, 16 months progress, teeth aligned, space nearly closed.

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{{PAGE_71}} Case #3: Progress (cont.) At that point, the issue of genioplasty was brought up again. His appearance on smile was significantly improved (image 1), but he was now aware that chin deficiency was a major part of his esthetic problem.

The cephalometric radiograph (image 2) clearly shows the protrusion of the lower incisors relative to the chin. Cephalometric superimposition (image 2, right) shows that the alignment in both arches was done with little change in incisor position—the incisors in both arches had been retracted very slightly. In this tracing, the pretreatment position is the solid line.

Ronald requested further information about surgical repositioning of his chin.

Image 1, progress, face: Improved smile, obvious chin deficiency, and poor throat form on profile view. Image 2, ceph / tracing: Protrusive lower incisors, little change in incisor position during treatment.

Case #3: Computer Image Prediction It is possible now to use computer technology to show patients the probable outcome of a procedure like moving one of the jaws or the chin. The prediction is based on making the bony change on the cephalometric tracing and using algorithms that relate soft tissue to hard tissue change to create the predicted soft tissue image.

For Ronald, a cephalometric prediction tracing was prepared in a computer imaging software program (Dolphin Imaging) (image 1). Note that the chin has been moved forward. Then the prediction algorithms were used to produce the soft tissue profile change (image 2). At the chin, the soft tissue moves forward almost 1:1 with the hard tissue—note the corresponding amount of change in the bony and soft tissue chin created within the computer program. In the absence of growth, the predictions are quite accurate for chin position and reasonably accurate for lip changes.

Ronald was pleased with the orthodontic progress, and when he was shown the predicted effect of repositioning his chin (image 3), he liked it, so a lower border osteotomy to augment the chin was planned.

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{{PAGE_72}} Research has shown that showing patients computer image predictions of this type greatly improves their ability to understand the esthetic implications of orthognathic surgery procedures. The research also shows that (if the predictions are realistic) there is little or no risk of raising expectations that cannot be met.

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{{PAGE_73}} Image 1, ceph prediction: Cephalometric prediction of chin augmentation.

Image 2, profile prediction: Ceph / soft tissue profile predictions.

Image 3, profiles compared: Present profile compared to prediction.

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{{PAGE_74}} Case #3: Lower Border Osteotomy These radiographs show the cut in the lower border of the mandible that is used to slide the bony chin forward. This improves both the projection of the soft tissue chin and throat form. The angle of the cut controls the extent to which the chin also moves upward as it is advanced. The surgery is done under general anesthesia, working intraorally from an incision in the depth of the mandibular vestibule. It does not require overnight hospitalization, and morbidity is equivalent to extracting premolars or molars bilaterally. If desired, submental fat can be removed at the same time to improve throat form—that was not done in this case. In the superimposition tracing, note the change in the position of the bony chin and in the profile. With a lower border osteotomy to reposition the bony chin, the soft tissue chin is augmented quite predictably.

Image 1, post-surg pan: Age 49, after lower border osteotomy to augment chin. Image 2, ceph/tracing: Cephalometric radiograph and superimposition tracing after chin augmentation.

Case #3: Treatment Outcome Treatment was completed and the orthodontic appliances were removed 5 months after the genioplasty, with a total treatment time of 19 months. With the canines in the lateral incisor positions, the midline was almost completely corrected (image 1). Because the lower incisors were not appreciably retracted, overjet remained nearly ideal (image 2). Toward the end of the orthodontic treatment, the canines were recontoured to make them look more like lateral incisors. Note that the high gingival margin of the canines is noticeably different from what would be expected for lateral incisors—but Ronald does not show the gingival margins when he smiles, so only the morphology of the lower two-thirds of the crown is important in his smile esthetics.

{{PAGE_75}} Image 1, frontal intraoral: Age 50, completion of treatment. Image 2, profile intraoral: Age 50, completion of treatment. Image 3, right lateral view: Age 50, completion of treatment. Image 4, left lateral view: Age 50, completion of treatment. Image 5, composite views: Age 50, completion of treatment.

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{{PAGE_76}} Case #3: Treatment Outcome (cont.)

These images show the facial change at age 49, from just prior to the genioplasty to 5 months later.

Because the gingival margins of the upper teeth are not seen on smile (image 1), even on a broad smile beyond what is pictured here, the canine substitution for the lateral incisors is esthetically acceptable, and the midline deviation has been corrected to the point that it is no longer immediately noticeable.

The three-quarter view (image 2) shows the increased chin projection and the tightening of skin contours created by moving the chin forward, which contributes to a younger look after the genioplasty.

On the profile view (image 3), greater chin prominence and improved throat form are apparent. Although dentists often do not consider the esthetics of the throat area, it is an important factor in overall facial esthetics.

The presurgery profile, computer prediction and actual outcome are shown in image 4. The presurgery profile is on the left, the computer image prediction in the center, and the actual profile on the right. Patients usually consider, as Ronald did, that the actual result looks better than the computer image prediction. He was pleased with the outcome in terms of both his dental and facial appearance.

Did the treatment affect his life adjustment? After treatment, he left his previous job and started his own English-language newspaper in a European city. It is reported to be quite successful.

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{{PAGE_77}} Image 1, frontal view: Frontal view before/after genioplasty. Image 2, oblique view: Oblique view before/after genioplasty. Image 3, profile view: Profile view before/after genioplasty. Image 4, prediction / result: Prediction compared to actual result.

Summary/Conclusions

Orthodontics for adults makes up about 20% of specialty practice now. The motivation for adults is different, and sometimes difficult to ascertain. There are two distinct groups of adult orthodontic patients:

1. Those who want to improve their situation They are: younger; motivated primary by psychosocial considerations (want to get ahead in the world); candidates for comprehensive rather than adjunctive treatment; and interested in the appearance of the orthodontic appliance, so are candidates for clear brackets, lingual orthodontics, or Invisalign.

2. Those who want to keep what they have They are: older; motivated primarily by concerns about their oral health and jaw function; candidates for adjunctive rather than comprehensive treatment; and not particularly concerned about the appearance of the appliance (bonded metal brackets are just fine).

{{PAGE_78}} Periodontal considerations always are important:

• Pocketing/mucogingival problems are likely to be present
• Bone loss affects orthodontic forces/moments

Patient management can be more difficult:

• Adults don’t adapt as well to orthodontic treatment
• Pain control requires medication, with Vioxx 50 mg a good choice
• Explanation and reassurance take additional time

But orthodontics for adults can be a highly gratifying part of all types of dental practice. It brings dentists in family practice and specialty practice into treatment teams, in a way that is stimulating to the practitioners and beneficial to the patients. Better dentistry is the result.

Self-Test Referral

The self-test section of this program is designed to help you be sure you have understood the material. Take it now, and use it as a guide for further study and review.

Copyright 2003, UNC Dept. of Orthodontics

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{{PAGE_79}}

3. Complex Adjunctive Treatment

Sequencing Complex Treatment

Sequence of Treatment

What is complex adjunctive orthodontic treatment? We will define it as extensive treatment that involves multiple dental specialties in addition to orthodontics. These patients are likely to require endodontics, periodontics, oral/maxillofacial surgery, implants, and restorations of all types.

As an example, consider James’s problems. He says, “I know it’s time to get my teeth fixed up.” He has lost multiple teeth, severe wear on lower incisors, evidence of active periodontal disease, and several teeth requiring restorations.

{{PAGE_80}} Sequence of Treatment (cont.)

Note the severity of the Class II malocclusion, with excessive overjet and overbite (images 1-3). This complicates the treatment of his other dental problems.

His facial proportions indicate (image 4) and cephalometric analysis confirms (image 5) that the malocclusion is due to a combination of maxillary dental protrusion and skeletal mandibular deficiency.

Note the relationship of the maxillary incisors to the maxilla: severely tipped and well forward from the anterior extent of their supporting bone.

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{{PAGE_81}} Also note how far the chin is behind a true vertical line dropped from nasion. The maxilla (point A) is slightly behind this line, the mandible (points B and pogonion) are well behind it. The skeletal Class II, therefore, is due entirely to mandibular deficiency.

{{PAGE_82}}

{{PAGE_83}} Sequence of Treatment (cont.) Given a patient with such extensive treatment needs, how do you sequence the treatment? The principle is simple, though the application may not be.

First, active disease must be brought under control (image 1). This would involve extraction of hopeless teeth, periodontics at the level needed to control active disease, endodontics as needed to maintain important teeth, and restorations (perhaps temporary ones) for caries control. For James, the first step consisted entirely of perio control.

Second, correct the alignment and occlusion of the teeth and do what is necessary to obtain acceptable dental esthetics and facial proportions.

Keep in mind why James wants his teeth fixed: For better health and function, but especially to improve his chances of getting ahead in the world—which means that his post-treatment facial appearance is important.

This second stage involves orthodontics and, if needed, orthognathic surgery (image 2). For James, mandibular advancement surgery was needed to put him in a position where satisfactory replacement of missing teeth was feasible. It also removed the “weak chin” appearance. In this image, you can see the screws in the mandibular ramus to hold the segments while healing occurs after mandibular advancement.

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{{PAGE_84}} Image 1, disease control: First step: disease control. Image 2, dentofacial correction: Second step: correct facial proportions and dental occlusion.

Sequence of Treatment (cont.)

Third, provide definitive periodontics (anything needed for long-term maintenance, for example, bone or soft tissue grafts) and definitive restorative dentistry. That could mean implants, onlays, crowns, fixed or removable partial dentures. Typically, it would include replacement of temporary restorations that were placed for disease control until the occlusion could be corrected.

At that point, the benefit of the orthodontic component of treatment for restoration of missing teeth becomes apparent. Because crowns/bridge abutments etc. can be fabricated more ideally, the restorative dentistry has a better long-term prognosis.

For James, the last step in treatment was extensive posterior restorations including bridges on the right side, which you can see in this cephalometric radiograph at the completion of treatment (image 1).

The facial change created by putting the mandible in its proper position can be seen in image 2. Would you agree that the stronger chin makes him look more confident and more competent? The pretreatment person would be easier to push around?

Because the dental relationships were normal after the mandibular advancement and orthodontic finishing, no compromises in the restorations were necessary (images 3-5). An implant-supported

{{PAGE_85}} partial denture on the right side was deferred because of cost—premolar occlusion on that side was acceptable. It should be possible now for him to maintain dental health.

As often is the case, the treatment changed his own view of what he could accomplish. He quit his job in a service industry after taking classes in computer programming while the treatment was being carried out and embarked on a new career.

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{{PAGE_86}} Image 1, finish ceph: Cephalometric radiograph at completion of treatment. Third, final perio / restorative As needed:

• grafts, etc.
• implants
• fixed / removable prosthodontics James, age 29, completion of treatment

Image 3, right lateral: Change in dental occlusion.

Image 4, frontal intra-oral: Change in dental occlusion.

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{{PAGE_87}} Sequence of Treatment (cont.) Some special points about the sequencing of complex treatment. (1) Teeth that have had endodontic treatment can be moved orthodontically. Their periodontal ligament remains normal, and the response to orthodontic force is similar. Some reports have indicated a greater risk of root resorption with tooth movement after endodontics, others have found no difference or even less root resorption. The best evidence is that root resorption is not a major concern when endo-treated teeth are moved. But orthodontic movement may be the last straw for a tooth with a traumatized or sensitized pulp. A patient with a tooth that may need endo treatment must be warned that it is possible for it to flare up and require treatment when orthodontics begins. For this patient (images 1-5), in order to align severely crowded incisor teeth, the lower left first premolar was extracted. Despite the periapical area that required apicoectomy, the first molar was retained, and it responded normally to orthodontic tooth movement after the endodontic re-treatment.

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{{PAGE_88}}

*Image 1, pre-treatment crowding: Mandibular arch prior to treatment.* </td> <td> *Image 2, pre-treatment periapical area: Periapical area lower left first molar prior to treatment.* </td>

*Image 3, orthodontic progress: Orthodontic progress, premolar extraction space closed.* </td> <td> *Image 4, post-treatment periapical area: Orthodontic treatment in progress after apicoectomy.* </td>

</td> <td></td>

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{{PAGE_89}} Sequence of Treatment (cont.) Some special points about the sequencing of complex treatment.

(2) Temporary restorations to control caries or replace unsatisfactory ones often are needed prior to orthodontics or surgery to correct the occlusion, but the temporary restoration must last for the duration of the orthodontic treatment, i.e., up to two years.

Susan, who was a candidate for orthognathic surgery, had poor crowns on her previously fractured maxillary central incisors (image 1). These had to be replaced in the first stage of treatment (disease control) to control the gingival inflammation (image 2). Temporary acrylic crowns were used during the duration of the orthodontic treatment (image 3), then new porcelain crowns were placed soon after the orthodontic appliance was removed (images 4, 5).

Crowns on incisors in patients with excessive overjet often are made thick faciolingually in order to obtain occlusal contact of the incisors. The thick crowns make it impossible to correct the overjet during orthodontic treatment, so even a well-fitting crown on an upper incisor may have to be removed if it is too thick. Sometimes an old crown can be retained during treatment after it has been extensively reshaped, and then replaced after the occlusion has been corrected.

{{PAGE_90}} Image 1, pre-tx crowns: Prior to treatment, unsatisfactory crowns on central incisors.

Image 2, temporary crowns: Temporary crowns in place, just prior to orthognathic surgery.

Image 3, during tx: Temporary crowns, after orthognathic surgery, during finishing orthodontics.

Image 4, permanent crowns: Permanent crowns, placed soon after completion of orthodontics.

Image 5, tx sequence: Overview of treatment sequence.

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{{PAGE_91}}

Sequence of Treatment (cont.)

Some special points about the sequencing of complex treatment.

(3) It is critically important for patients with complex problems to be seen regularly for perio maintenance during active orthodontics. The recall schedule is established from the patient’s needs, but often scaling/curettage is needed at 2-3-month intervals.

For this patient, extraction of periodontally involved incisors with a poor long-term prognosis (image 1) made it possible to align the severely crowded anterior teeth in both arches (images 2, 3) and improve the chances of maintaining the remaining teeth. Continued perio recall at 3-month intervals during the orthodontic treatment was an important part of patient management.

Periodontal problems must be brought under control before orthodontic treatment begins and must be kept under control during the orthodontics.

Image 1, pre-tx: Prior to treatment. Image 2, extractions: Incisor extractions, perio treatment continuing. Image 3, progress: Alignment progress, frequent perio recalls scheduled.

Sequence of Treatment (cont.)

Some special points about the sequencing of complex treatment.

(4) Careful coordination between the end of orthodontic treatment and the final restorative work is important. The time in orthodontic retainers before restorations are placed should be minimal. Waiting to start the restorative dentistry “until things settle down” is a recipe for problems.

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{{PAGE_92}} Think of it this way: Bridges/implants serve as permanent retainers after the orthodontics. The removable retainers typically used after orthodontics in adolescents rarely are satisfactory even for short times in adults awaiting fixed prosthodontics. Bonded or thermoplastic (suckdown) retainers are better, but not as good as fixed prostheses. Bottom line: When the braces come off, get on with the restorative work sooner rather than later. For James, the patient whom we just looked at, the bridges are permanent retainers.

Case #1: Implants or Bridges?

Case #1: Implants vs Bridges Now let’s look at a patient who illustrates important considerations in answering two common clinical questions:

1. close old extraction spaces, or open them for prosthetic replacements?
2. implants or bridges to replace missing teeth?

June (images 1-5) was age 45 when she sought treatment. She was concerned about the appearance of her teeth and wanted her missing molars replaced. Her comment: “I paid for orthodontics for two kids and just finished putting both of them through college. Now it’s my turn.”

{{PAGE_93}} As she put it, she “smiled a crooked smile” because the maxillary left lateral incisor was congenitally missing. Composite had been added to the mesial of the canine to partially conceal the missing tooth, but the asymmetry was obvious when she smiled.

All four first molars were missing. In the maxillary arch the extraction space was closed on the right side, partially open on the left. Both lower second molars were severely tipped mesially, and the left second molar was also displaced buccally. There was a significant buccal crossbite on the left.

There were restorations in most posterior teeth, with recent composites placed for caries control in mandibular second premolars.

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{{PAGE_94}} Image 1, facial appearance: June, age 45, prior to treatment. Image 2, frontal intraoral: June, age 45, prior to treatment. Image 3, right lateral: June, age 45, prior to treatment. Image 4, left lateral: June, age 45, prior to treatment.

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{{PAGE_95}}

Case #1: Initial Records

When these initial orthodontic records were taken, she had already undergone restorative and perio treatment for control of active disease. The displaced teeth are shown well on the panoramic radiograph. Note that there are no areas of extreme bone loss.

The key questions in planning further treatment were:

• how to manage the esthetic problem created by the missing maxillary lateral incisor
• how to manage the maxillary first molar extraction sites, one of which was already closed
• how to manage the mandibular first molar extraction sites, with severely tipped second molars
• how to replace missing teeth if spaces were opened (bridges or implants?)

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{{PAGE_96}} Case #1: Treatment Plan For incisor esthetics, symmetry is always important. This was a major factor in planning treatment for June. It would be very difficult to restore the maxillary left canine to make it an acceptable substitute for the missing lateral incisor, especially because its gingival margin was so different from the natural lateral on the other side. Opening space for replacement for the lateral incisor was feasible because space for the missing first molar in the same quadrant could be closed as this was done.

Her occlusion also was a factor: She was almost in anterior crossbite, and slightly advancing the maxillary incisors would improve the incisor relationships in function.

Thus the plan for the maxillary arch was to:

• open space for a prosthetic lateral incisor, and
• close the first molar extraction sites.

An important factor in the decision: Recent research has shown that unlike the lower arch, good periodontal health is possible with upper second molars tipped mesially, so there was no compelling reason to try to bring the roots of the upper second molars mesially.

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{{PAGE_97}} Case #1, Treatment Plan (cont.)

In the mandibular arch, closing the old first molar extraction sites would be extremely difficult and time consuming. To do that, it would be necessary to place implants in the mandibular ramus to serve as anchorage to bring the second and third molar roots mesially. As these molars were moved mesially, they also would have to be moved even further lingually to correct the crossbite.

In contrast, if the mandibular third molars were extracted, tipping the second molars upright would be straightforward and would have the added advantage of improving periodontal health on the mesial of these teeth. Mesially tipped lower molars are at risk periodontally.

The question of implants versus bridges for the three replacement teeth that would be needed was left open at the time the orthodontics was begun.

Case #1, Treatment Plan (cont.)

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{{PAGE_98}} For severely tipped lower molars, an auxiliary uprighting spring (images 1, 2) often is the most effective way to begin the necessary tooth movement. For June, the uprighting spring could be contoured to tip the lower right second molar lingually as it uprighted. Often lingual tipping is an undesirable side effect of uprighting springs—for her it was an advantage.

After 10 months of treatment, the lower molars had been uprighted (images 3, 4). The maxillary lateral incisor space had been opened, and a prosthetic lateral incisor was attached to the arch wire. This creates a highly esthetic replacement, but it needs to be attached to a rigid rectangular wire for stability.

Note the use of bonded attachments on the molars as well as the other teeth. If possible, bands should be avoided in patients with previous perio problems around molar teeth. In June’s case, curettage on the mesial of the second molars as they uprighted was an important part of the treatment.

At 14 months the maxillary space had been closed, but (as planned) the upper molars still were tipped mesially. As we have noted, mesially tipped upper molars are much more compatible with good periodontal health than mesially tipped lower molars. At that point uprighting of the lower molars had nearly been completed.

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{{PAGE_99}} Image 1, uprighting diagram: Diagrammatic representation, uprighting a severely tipped lower molar by tipping it distally.

Image 2, uprighting spring: Uprighting spring in place.

Image 3, 10 months, right side: 10 months progress: molar uprighted, crossbite corrected.

Image 4, 10 months, left side: Lateral incisor space opened, pontic in place; molar uprighted, crossbite greatly improved.

Image 5, 14 months, pan: 14 months progress.

Case #1: Progress At 18 months, treatment was nearly complete (images 1-5).

Between 14 and 18 months, a coil spring was used in the maxillary arch to make space for a larger permanent lateral incisor prosthesis. Coil springs were used to further open the mandibular molar extraction sites after the initial uprighting was completed, and then segments of closed coil over the arch wire were placed to maintain the space.

Note that there was minimal overjet at this point. Fortunately the upper second molars could be left in their mesially tipped position, because any force system to bring their roots mesially would tend to retract the upper incisors, and that would have brought her into anterior crossbite.

{{PAGE_100}} Image 1, frontal: June, age 46, 18 months progress. Image 2, right lateral: June, age 46, 18 months progress. Image 3, left lateral: June, age 46, 18 months progress. Image 4, max occlusal: June, age 46, 18 months progress. Image 5, mand occlusal: June, age 46, 18 months progress.

Case #1: Implant vs Bridge Decision

At this point, with orthodontic treatment nearly completed, decisions as to implants versus bridges had to be made. The greater cost of implants was a factor, but June wanted the best quality of result and would consider implants.

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{{PAGE_101}} For her, a single tooth implant to replace the maxillary lateral incisor offered better esthetics than a bridge and would not require crowns on the central incisor and canine (image 1).

In the lower arch, however (image 2), implant placement was complicated by the loss of bone at the old extraction sites, especially on the left side. Bone grafting would be needed before an implant could be placed there. The lower second molars and the right second premolar needed permanent restorations and would benefit from crowns.

The decision, therefore, was an implant in the maxillary incisor region and bridges in the lower arch.

Case #1: Sequencing of Implant Placement with Final Orthodontics

The interaction between completion of orthodontics and implant placement is an important consideration. Note (images 1-3) that at 24 months after the beginning of treatment, an implant had been placed in June’s maxillary arch. The orthodontic appliance had been removed in the mandibular arch, and bonded wire retainers were in place, but the maxillary orthodontic appliance remains in place—why?

The reason is that the orthodontic appliance is an effective way to supply a pontic for the esthetically sensitive maxillary incisor area while healing around the implant site occurs. The pontic tied to the arch wire avoids any contact with the soft tissue over the implant. This could be a problem if a removable retainer with a replacement tooth were used.

Note the bonded retainers in the lower arch to maintain the incisor alignment and control the molar spaces. Fixed, not removable, retainers are preferred in complex treatment. Fabrication of the lower bridges could have started at this point but were delayed until the implant crown was completed.

With the orthodontic appliance still supplying the temporary pontic (images 4, 5), a connective tissue graft was placed on the facial of the lateral implant area, and a healing abutment was attached.

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{{PAGE_102}} Image 1, 24 months pan: June, age 47, 24 months progress, maxillary implant, mandibular fixed retainers. Image 2, maxillary occlusal: June, age 47, 24 months progress, maxillary implant in place but not yet uncovered, pontic tied to arch wire. Image 3, mandibular occlusal: June, age 47, 24 months progress, mandibular fixed retainers in place, awaiting bridge fabrication. Image 4, connective tissue graft: Connective tissue graft to facial of implant.

{{PAGE_103}} Image 5, healing abutment: Healing abutment in place.

Case #1: Completion of Orthodontic Treatment

Four months after that, the orthodontic appliance was removed, and the finished crown was placed on the implant. The fixed retainers remained in place in the mandibular arch until fabrication of the bridges was started. Fixed retainers are particularly advantageous when there will be more than a few months of delay between removal of the orthodontic appliance and placement of the permanent retainers (the bridges), as there was for this patient, while the implant crown was completed—but fabrication of the mandibular bridges could have been done at any time after the orthodontic appliance was removed.

Case #1: Completion of Orthodontic Treatment (cont.)

Extracting the third molar and uprighting the second molar, as was done for June, brings the upper and lower second molars into occlusion. The sequence of treatment is shown in images 1-3. Bone fill-

{{PAGE_104}} in on the mesial of the uprighted molar occurs if periodontal health is maintained in that area (which should be curetted during the uprighting). Comparison of the panoramic radiographs before and after treatment (image 4) shows the tooth movement. Note that preparation of one of the bridges had begun at this point, soon after the upper appliance was removed and the crown was placed on the implant.

Image 1, pre-tx: Mesially tipped second molar, third molar in place.

Image 2, 3rd molar extracted: Mesially tipped second molar after extraction of third molar.

Image 3, 2nd molar uprighted: Note bone fill-in on mesial of uprighted second molar.

Image 4, comparison: Pre- and posttreatment panoramic radiographs.

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{{PAGE_105}} Case #1: Completion of Treatment June was pleased with the appearance of her teeth and especially with the improvement in her smile esthetics (image 1). Although there were minimal changes in her profile, note that the treatment increased support for her upper lip (image 2). This was a part of the esthetic improvement. With the bridges in place, she had satisfactory occlusion. Excellent dental health was observed on her recent 6-year recall (images 3-5). For her, this mixture of implant and bridges provided an excellent outcome.

{{PAGE_106}} Image 1, smile change: June, age 45 to 47, change in smile esthetics.

Image 2, profile change: June, age 45 to 47, change in profile.

Image 3, frontal: June, age 53, 6-year recall.

Image 4, right lateral: June, age 53, 6-year recall.

Image 5, left lateral: June, age 53, 6-year recall.

Case #2: Perio / Orthognathic Surgery / Restorative

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{{PAGE_107}} Case #2: Orthognathic Surgery

Now let’s look at a second patient needing complex adjunctive treatment.

Jim sought treatment at age 43 because he needed a better replacement for his missing upper incisors. He didn’t like the appearance of his present partial denture when he smiled, felt that it didn’t fit properly anyway, and was concerned that he was on the way to losing all his teeth.

Facial proportions are somewhat difficult to assess in the presence of a beard—one of the reasons for wearing it, of course—but you can see that he has a degree of mandibular deficiency.

Case #2: Initial Intraoral Appearance

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{{PAGE_108}} He had a very deep bite, with the lower incisors against the palatal portion of the partial denture when it was in place and right against the palate without it. The mandibular arch was almost telescoped within the maxillary arch.

All mandibular posterior teeth were missing on the left side, and the maxillary teeth had supererupted. The mandibular right first molar was missing, and the second molar had tipped mesially. Both second premolars had broken-down restorations and active caries.

There was evidence of active periodontal disease, i.e., bleeding on probing in several areas.

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{{PAGE_109}} Image 1, partial denture in: Jim, age 43, prior to treatment. Image 2, denture out, overbite: Jim, age 43, prior to treatment. Image 3, right lateral view: Jim, age 43, prior to treatment. Image 4, left lateral view: Jim, age 43, prior to treatment.

{{PAGE_110}} Case #2: Initial Radiographs Both mandibular second premolars had had previous endodontic treatment (image 1), and there was a questionable periapical area for the right second premolar. Moderate bone loss in both maxillary posterior quadrants was apparent.

In the panoramic radiograph, note the supereruption of the maxillary molars on the left side, where opposing teeth were lost many years previously. There is not enough vertical space for a partial denture for the mandibular left area.

The cephalometric radiograph and tracing (image 2) showed severe mandibular deficiency, with poor lip support from the teeth in both arches. Lower face height was short, both in comparison to normal dimensions and (more important) in relation to the width of his face. There was an extreme curve of Spee in the lower arch due to elongation of the mandibular incisors.

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{{PAGE_111}} Case #2: Treatment Plan The plan for Jim followed the sequence guidelines. The first thing to be done was to control his oral health problems (image 1):

• extract the mandibular right third molar
• perio control procedures
• temporary restoration of the mandibular right second and left first premolars, the previously endo-treated teeth
• reevaluate the endodontic status of these teeth

With the dental health problems under control, the plan for the second and third stages of treatment (image 2) was:

• maxillary orthodontic appliance, with replacement pontics for the upper incisors attached to it, to align and level
• mandibular orthodontic appliance, uprighting of second molar
• ramus surgery to lengthen the mandible
• postsurgical leveling of the mandibular arch
• replacement of missing teeth with a fixed prosthesis in the upper arch and on the mandibular right, and a removable partial denture for the lower left posterior area (selected instead of implants primarily because of cost).

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Case #2: Progress Presurgery

After 8 months, disease control and the presurgical orthodontics had been completed, and he was ready for the orthognathic surgery to advance his mandible and rotate it down anteriorly. At this point, of course, facial proportions were unchanged (images 1-3).

As soon as a rigid arch wire could be put in the upper arch, prosthetic teeth were tied to it. Although prosthetic teeth tied to an arch wire leave something to be desired in function, they look quite realistic, and his previous partial was so bad that almost anything would have been better.

In the cephalometric radiograph (image 4), the stabilizing arch wire to be used at the time of surgery can be seen, with the prosthetic teeth attached to it. The vertical hooks soldered to the arch wire, which can be seen in the radiograph, are used in the operating room to hold the teeth in the planned occlusion while screws across the osteotomy site are placed to hold the jaw segments during healing. With this approach, it is not necessary to wire the jaws together during healing, and patients are much more comfortable even though they still must be on a restricted diet. Patients often think that if the surgeon “breaks my jaw,” they will have to have their teeth wired together for weeks—not true now. You can reassure them that their jaw isn’t broken, it’s cut carefully, and that they won’t be wired shut.

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Case #2: Progress Presurgery (cont.)

The heavy stabilizing arch wires placed in both arches for stabilization at surgery, with soldered brass hooks to facilitate wiring the jaws together in the operating room, can be seen in these presurgical views.

Note that the anterior deep bite has not been corrected prior to surgery. Instead, the mandible will be rotated so that the chin moves downward and forward, increasing anterior face height. This is an important part of the surgical change, which corrects not only the anteroposterior mandibular deficiency but also the short face height.

Note also the uprighting of the mandibular left second molar after extraction of the third molar. The coil spring used for distalization after uprighting is still in place, but it must be passive at this point. Further tooth movement can be accomplished postsurgically if needed. For Jim, the plan is leveling of the lower arch postsurgically after proper vertical incisor relationships are established.

Cephalometric superimposition on the cranial base for the presurgical phase of treatment (image 4, right) shows that some downward-backward rotation of the mandible occurred. Further mandibular rotation downward will be accomplished at surgery, along with advancement of the chin. This increases face height and allows correction of the anterior deep bite.

The maxillary and mandibular superimpositions (image 4, left) show the amount of tooth movement in each arch. Note the distal movement of the lower molar as it was uprighted.

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{{PAGE_115}} Image 1, right lateral: Jim, age 44, ready for surgery, stabilizing arch wires.

Image 2, left lateral: Jim, age 44, ready for surgery, stabilizing arch wires.

Image 3, frontal: Jim, age 44, ready for surgery, stabilizing arch wires.

Image 4, cephalometrics: Cephalometric superimpositions: cranial base (left), maxilla, and mandible.

Case #2: Immediate Postsurgery The facial photos in image 1 were taken at 6 weeks postsurgery, at the time he returned for completion of the orthodontic treatment. Despite the beard that he started regrowing immediately after surgery, the improvement in facial proportions is obvious. Often in mandibular deficient patients, increasing face height is as important as bringing the chin forward. At that point, both the plastic splint that was maintained interocclusally after surgery and the stabilizing arch wires were removed. Downward rotation of the mandible as it was advanced had corrected the anterior deep bite (images 2-3). Lighter working arch wires were placed, and Jim wore light elastics as he accommodated to the new mandibular position (note the elastic hooks formed from modified ligatures on canine brackets). After patients have undergone jaw surgery, they are Level IV Clinical Treatment — Unit B · 115 / 148

{{PAGE_116}} highly motivated to obtain an excellent result, so cooperation with elastics and other aspects of treatment rarely is a problem.

In the panoramic radiograph at 6 weeks postsurgery (image 4), the titanium screws used to hold the mandibular segments during healing can be seen. Although these can be removed, usually they are not, because unless they cause a problem, which is quite unusual, there is no reason to put the patient through additional surgery to remove them.

Cephalometrically, the improvement in mandibular position is apparent (image 5). The cephalometric superimposition pre- to postsurgery shows the extent to which both face height and chin prominence were increased by rotating the mandible downward as it was brought forward. This pattern of mandibular rotation at surgery is quite stable and predictable, which makes it the best way to correct skeletal deep bite (deep bite caused by inadequate face height).

{{PAGE_117}} Image 1, post-surg face: Jim, age 44, 6 weeks after surgery. Image 2, right lateral: Jim, age 44, 6 weeks after surgery.

Image 3, left lateral: Jim, age 44, 6 weeks after surgery.

Image 4, post-surg pan: Panoramic radiograph postsurgery: note fixation screws.

Image 5, ceph: Postsurgical ceph and superimposition: downward-forward movement of the mandible.

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{{PAGE_118}} Case #2: Completion of Orthodontics

Five months later, the postsurgical orthodontics was completed and the orthodontic appliance was removed. Since the maxillary incisor pontics were tied to the arch wire, replacement teeth were needed immediately (image 1). Correction of the deep overbite has made prosthetic replacement of the missing teeth much easier.

A temporary maxillary fixed bridge was placed as soon as the orthodontic appliance was removed (images 2-4). It served as a fixed retainer for the maxillary teeth. No other maxillary retainer was needed.

In the mandibular arch (image 5, top), a removable retainer was needed initially to maintain both the pontic space on the right side and the vertical space for lower replacement teeth on the left. The retainer was thick enough in the mandibular left posterior area to provide occlusal contact with the upper molars, to control any tendency for the upper teeth to elongate.

A temporary mandibular fixed bridge was placed in the mandibular right quadrant within the next month, and the removable lower retainer was modified to accommodate its presence (image 5, bottom). The removable retainer still was needed to prevent further eruption of the upper left teeth until a partial denture could be supplied.

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{{PAGE_119}} Image 1, post-treatment frontal: Completion of orthodontics, temporary pontics removed. Image 2, temporary bridge, occlusal: Temporary maxillary fixed bridge, placed immediately after removal of the orthodontic appliance. Image 3, temporary bridge, right lateral: Temporary maxillary fixed bridge, placed immediately after removal of the orthodontic appliance. Image 4, temporary bridge, left lateral: Temporary maxillary fixed bridge, placed immediately after removal of the orthodontic appliance.

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{{PAGE_120}} Image 5, mandibular arch / retainer: Top: Mandibular arch at end of treatment; bottom: lower removable retainer to maintain vertical position of upper teeth above the lower edentulous area.

Case #2: Completion of Orthodontics

The panoramic radiograph at 3 months after the orthodontic appliance was removed (image 1) shows the crown/bridge preparations in both arches. Although the endodontically treated lower premolars were repositioned orthodontically, further endo treatment was not necessary—but the patient was prepared for that possibility.

The definitive prosthodontics, with fixed prostheses in the maxillary anterior and mandibular right posterior, and a mandibular removable partial denture to replace the missing teeth on the lower left (images 2, 3), was completed within the next 9 months. Jim was very pleased with the improved appearance on smile (image 4).

An alternative plan, of course, would have been placement of an implant in the mandibular left posterior region to serve as a posterior abutment for a fixed bridge. The additional cost and time of doing that, which would have required a bone graft before the implant could be placed, made the removable partial a better choice for this patient. Temporary bridges are satisfactory orthodontic retainers, so if these are used, there is less urgency to place the permanent restorations, but it is

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{{PAGE_121}} desirable to complete the prosthodontic phase of treatment as soon as possible after the orthodontics is completed. The end-of-treatment panoramic radiograph (image 5) shows the final fixed prostheses in place, with good periodontal health at this point. The occlusion was stable during the fabrication of the prostheses. For Jim, as for other patients with similarly complex problems, careful integration of the various phases of treatment was a key to success.

{{PAGE_122}} Image 1, prosthetic progress pan: Panoramic radiograph 3 months after removal of orthodontic appliances.

Image 2, lateral view, restorations: Completed restorations 9 months after completion of orthodontics, lateral views.

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Image 3, occlusal view, restorations:

Completed restorations, occlusal views.

Image 4, frontal view: Dental and facial

esthetics, frontal views.

Image 5, prosthetic completion pan:

Panoramic radiograph after completion of restorations.

Summary and Conclusions

In summary:

• Complex adjunctive orthodontic treatment requires a team of dentists for treatment because it requires orthodontics, periodontics, restorative dentistry and often other dental specialties (endodontics, prosthodontics, oral-maxillofacial surgery). A major goal of the orthodontic treatment is to facilitate treatment of the patient’s other needs.

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{{PAGE_124}} Sequence of treatment is important: First, disease control periodontics endodontics extractions temporary restorations Second, correction of the alignment/occlusion orthodontics orthognathic surgery Third, definitive perio/restorative/prosthodontics

Important special considerations in complex adjunctive treatment: Tooth movement can be the last straw for a tooth on the borderline for requiring endo treatment; fortunately, endo-treated teeth can be moved orthodontically Temporary restorations will have to last for the duration of orthodontic treatment, so should be good for 2 years Perio maintenance during orthodontics often means frequent perio recall Coordination between the end of orthodontics and the final restorative/prosthodontic treatment is important—there should be minimal delay between the completion of orthodontics and the final restorations

Self-Test Referral The self-test section of this program is designed to help you be sure you have understood the material. Take it now, and use it as a guide for further study and review.

Copyright 2003, UNC Dept. of Orthodontics

{{PAGE_125}} 4. Orthodontic Retention

Retention: Why?

Overview of Retention

Why, even if you’re not treating complex orthodontic problems, do you need to know something about orthodontic retainers? Because you will be seeing patients in your family practice or specialty practice who are wearing them—or should be. When a retainer is lost or broken, often you’re the first dentist who is asked what to do next. And you will have to counsel patients about what would be required to get teeth back into alignment after relapse when a retainer was not replaced.

Did you have orthodontic treatment? If so you have already had some experience with retainers, so you can share personal experience, maybe even use yourself as an example. And if you didn’t have treatment yourself, you undoubtedly have had friends complaining to you about what happened with their retainers. So you already know at least a little about retention and retainers. The goals of this module are to

• Explain why retainers are necessary
• Describe the schedule and timing of retention
• Discuss the indications for and management of removable vs. fixed retainers
• Put retention in the perspective of interaction with orthodontists about patients that you have in common.

Why Are Retainers Necessary?

Retainers are necessary because orthodontic treatment outcomes are potentially unstable for three reasons:

1. The periodontal and gingival tissues are affected by tooth movement, and even in the best case they require time for reorganization after an active orthodontic appliance is removed.
2. Pressure by the tongue and lips / cheeks provides force against teeth that can result in tooth movement (the equilibrium effects that you have learned about previously).
3. Growth after treatment is likely to lead to adaptive changes in tooth position—which means potential instability until growth is completed even in patients who had no skeletal problem.

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Reorganization of PDL After Treatment

You will remember from Level III that widening of the periodontal ligament space and disruption of the collagen fiber bundles that connect the tooth to the adjacent bone is an essential part of tooth movement. Tooth mobility increases as the alveolar bone around them is remodeled. At the end of treatment, reattachment of the fibers to a new layer of bone is required.

Something you should remember but may have forgotten: the PDL plays an “active stabilization” role in equilibrium. Remember that soft tissue pressures against the teeth are not perfectly balanced (Image 1), and even very light but prolonged pressure can cause tooth movement. The PDL can compensate for an imbalance of a few grams but not more than that. An orthodontic appliance overcomes this stabilization—but until the PDL reorganizes after treatment, active stabilization doesn’t work, and the teeth are very sensitive to pressure imbalances that could be tolerated when reorganization is complete (Image 2).

An important concept: reorganization of the periodontal ligament does not begin until orthodontic archwires are removed and teeth can move relative to each other during function. Independent movement of teeth is impossible when they are splinted together, as they are during the finishing stage of treatment when stiff archwires are being used to obtain torque and precise positioning. So it simply isn’t true that if passive archwires were left in place for a few months after active tooth movement ended, PDL reorganization would be complete when they were finally removed.

Once displacement of a tooth relative to the one next to it can occur, i.e., once alveolar bone bending during function is back to normal, it takes 3-4 months for PDL reorganization to be completed. The slight mobility that is present when an orthodontic appliance is removed disappears over that period of time.

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{{PAGE_127}} The bottom line: every orthodontic patient is going to need something to maintain tooth position for a few months while the PDL is undergoing reorganization (Image 3).

Retention: Why?

1. Periodontal ligament effects

• Periodontal ligament fibers disorganized after ortho tx
• Cheek-lip/tongue pressures not balanced

Retention: Why?

1. Periodontal ligament effects

• Periodontal ligament fibers disorganized after ortho tx
• Cheek-lip/tongue pressures not balanced Equilibrium theory: “Active stabilization” by the periodontal ligament is needed to keep teeth in proper position.

Retention: Why?

1. Periodontal ligament effects

• Periodontal ligament fibers disorganized after ortho tx
• Cheek-lip/tongue pressures not balanced Active stabilization is not available until the PDL reorganizes after orthodontics, which takes 3-4 months after braces. Therefore, retention for this period of time always is needed.

Reorganization of the Gingival Tissues The soft tissues of the gingiva also are disturbed by orthodontic tooth movement, and remodeling of these tissues is needed as part of the adaptation to treatment. The gingiva contains both collagenous and elastic fibers, which reorganize more slowly than the PDL. At one year after alignment of the teeth the supracrestal elastic fibers still are stretched, particularly after a tooth has been rotated, and they exert enough force to cause immediate relapse. In orthodontic treatment, the first step is to align the teeth, and after that they are held in alignment. Unlike the PDL, gingival remodeling does start while an orthodontic appliance is in place (Image 1), so it helps that typical treatment takes another year or so after alignment is completed. But if the teeth were severely crowded and malaligned, at least another year of retention is likely to be needed (Image 2).

{{PAGE_128}} Severely rotated teeth can be almost impossible to retain unless the stretched gingival elastic fibers are relaxed by fiberotomy. That is a relatively simple surgical procedure which should be done before the active appliance is removed. It makes all the difference in maintaining a rotated tooth in its new position (Images 3, 4).

Retention: Why? 2) Gingival fiber effects

• Elastic fibers in the gingiva are stretched when teeth are moved
• Holding the teeth in alignment during the rest of treatment helps with gingival fiber adaptation But it takes a long time for adaptation to occur, and if teeth were irregular, at least another year after debanding is needed. Very different from PDL fibers.

Gingival fibers remodel very slowly, but their remodeling starts when alignment is completed. So holding the teeth in alignment during the rest of treatment helps with their gingival fiber adaptation.

Image 2

Image 1

Image 3, Fiberotomy surgery: Sectioning stretched gingival elastic fibers to prevent re-rotation is needed after correction of severe rotation. It is particularly important for maxillary incisors, where relapse is obvious every time the lips are separated. For these teeth, the surgical technique should be modified to maintain papilla height.

Image 4, Fiberotomy incisions before suturing: Note that the fiberotomy incisions do not go completely through the tip of the interdental papillae, to control loss of papilla height. Cuts on the lingual also are required.

Wisdom Teeth?

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{{PAGE_129}} From previous discussions of equilibrium, you already know that mandibular third molars are erupting, or attempting to erupt, at the same time in late adolescence that lower incisor crowding tends to develop even in patients who never had orthodontic treatment. And you already know that the culprit usually is some late mandibular growth that is not matched by maxillary growth.

You’re going to have to discuss third molars with all your adolescent and young adult patients. Should they be removed to prevent lower incisor crowding. No. Should they be removed for other reasons? For many of them, yes. Just be careful about blaming incisor crowding on third molars and using that as a reason for early extraction.

Growth: Class II / Deep Bite Patients For skeletal Class II and deep bite problems, comprehensive treatment is done during adolescence, for two reasons: the response to attempted growth modification is better then, and treatment often ends just as the adolescent growth spurt is coming to an end. The more a patient grows after the braces come off, the greater the chance that the original skeletal problem will reappear, as overjet develops and the deep bite returns (Image 1). That means that retention to maintain the jaw relationship and prevent eruption of lower incisors will be needed until growth subsides (Image 2).

{{PAGE_130}} Image 1, Post-treatment growth, Class II patient: Cephalometric superimposition. Black, immediately after correction of a Class II problem, age 13; red, recall, age 17. Note the post-treatment growth of the mid-face and maxilla, with minimal growth of the mandible, which led to a return of relative mandibular deficiency, overjet and deep bite.

Retention: Why? 3) Growth effects

• Normal late mandibular growth
• Return of skeletal pattern Even if growth modification has been successful, further growth will occur in the original pattern. Class II, Class III, deep/open bite problems require long-term retention.

Growth: Class III Patients Relapse due to late growth is even more of a problem for skeletal Class III and open bite problems. If a Class III patient has continued mandibular growth in late adolescence, as often occurs, not only will the lower incisors be tipped lingually at the expense of alignment, the increasingly prominent chin will become more of an esthetic problem (Images 1-4). As you already know, preadolescent treatment for Class III patients with maxillary deficiency is the modern recommendation, but if excessive mandibular growth occurs during adolescence, retention is very difficult, almost impossible, and orthognathic surgery at the end of the growth period may be required (image 5). The same is true for severe anterior open bite, which is largely caused by vertical growth of the maxilla that is not matched by vertical growth of the mandibular ramus. Treatment during adolescence can lead to temporary correction of the open bite—and if further vertical growth of the maxilla occurs, as it often does, intraoral appliances can’t control it. So delaying treatment until growth is complete or nearly complete is the best plan.

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{{PAGE_131}} Image 1: Age 7, prior to treatment for developing Class III problem.

Image 2: Age 8, after facemask (reverse-pull headgear) treatment.

{{PAGE_132}} Image 3: Age 13, after adolescent growth. Note the increased prominence of the chin.

Image 5: Age 19, after orthognathic surgery.

{{PAGE_133}} Summary

Based on what you just read, you should now understand that all patients who have had significant orthodontic tooth movement require retention. In a sense, you’re now seeing clinical application of things that you learned about growth all the way back in Level I, and that you learned about soft tissues and equilibrium in Level III.

It has been said repeatedly by some clinicians that “My method corrects malocclusion so perfectly that no retainers are necessary”. The thought—the fantasy—is that perfect dental occlusion would generate the forces necessary to keep the teeth where treatment put them. You already know better than that, because you know that patients rarely bring their teeth into the occlusion except when clenching or grinding. For better or worse, occlusion is not a retainer.

Should all patients get the same set of retainers? That makes no sense when you take a broader view of retention. Clearly, retainers should be designed to control the type of relapse would be expected for that individual patient. The guideline is that teeth tend to move back toward their original relationships within the dental arch and original occlusal relationship.

Retention: When? The Retention Schedule: Function as an Influence

Occlusion as seen on an articulator may not be a factor in retention, but occlusal function certainly is. We have described what it takes to obtain reorganization of the PDL: movement of the teeth relative to each other during chewing, and the bending of alveolar bone that accompanies mastication. Your teeth, of course, rarely come into occlusion when you’re eating.

What does that mean relative to retention? Should the patient be wearing a retainer all the time as soon as the braces are removed? The interesting, and perhaps surprising, answer is No.

Why not? Because the retainer would prevent the movement of teeth in function that is necessary for PDL reorganization. So during the first 3-4 months after treatment, removable retainers should be taken out to eat, and worn all the rest of the time. And if a fixed retainer is used, it must be made so that it is flexible enough to allow the desired tooth movement during function.

{{PAGE_134}} Retention: When? Two important influences on the retention schedule:

• Teeth must move relative to each other during chewing for PDL reorganization to occur

During first 3-4 months post-tx

• Removable retainers-taken out to eat, worn all the rest of the time
• Fixed retainers must allow movement

The Retention Schedule: Gingival Elastic Fibers Gingival elastic fibers remodel slowly. How does that fit into the retention schedule? For a typical patient who had crowded and malaligned teeth, even if the teeth were held in alignment for most of the orthodontic treatment time, the elastic fibers will still be at least somewhat active by the time PDL reorganization is complete. Fortunately, part-time retainer wear is adequate to control this, but wearing the retainer 10-12 hours per day for the rest of the first post-treatment year is needed. Does it make any difference which hours it is worn? Fortunately, evening and night hours (when patients are more likely to be compliant) are as good, perhaps even better, than daytime hours.

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Retention: When?

Two important influences on the retention schedule:

• Function necessary for PDL reorganization
• Teeth tend to move back to their original position

Elasticity of gingival fibers; part-time retention for at least 12 months.

The Retention Schedule: Tongue vs. Lip / Cheek Pressures What about tongue pressure versus lip and cheek pressures against the teeth? We have already talked about active stabilization by the PDL after its reorganization is complete—but remember that the PDL’s capacity to stabilize is limited to overcoming a few grams of pressure. What does that mean for retention? Simply that if the teeth have been put in a position where the soft tissue pressures are too great for PDL stabilization, retention will be needed long-term. If the dental arches were over-expanded, that’s the obvious conclusion—and many current orthodontic patients are being put into that situation.

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{{PAGE_136}} Retention: When?

Two important influences on the retention schedule:

• Function necessary for PDL reorganization
• Teeth tend to move back to their original position

• Elasticity of gingival fibers, tongue / lip-cheek pressures
• Until growth ends (permanent?)

Typical Retention Schedule

So where does that leave us relative to a typical retention schedule? It usually looks like the attached figure. Would that ever be modified? Of course it would, if the patient was exposed to things that this retention plan would not control, or if he or she were not exposed to things that it does control.

The goal, of course, is to retain what is likely to change without retention.

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Retention: When?

Typical retention schedule:

• Full-time except during eating, for the first 3-4 months
• Part-time for the next 8-9 months
• Continue part-time until growth is complete
• If pressures unbalanced, continue indefinitely

Retention: How?

Maintaining Alignment

Now let’s look at how retention is done. The principle: How you do it is primarily determined by what you’re trying to control, then secondarily by practical considerations like the difficulty of fabricating what is needed and the acceptability of the retention device to patients.

A primary goal for patients who have treatment to correct crowding and malalignment of the teeth is to maintain alignment (Image 1). Sounds obvious, doesn’t it? But that leads directly to an important consideration: this requires two-point contact on each tooth. If you don’t have that, just as with an appliance to move teeth, you don’t have control.

How do you get two-point contact? A retainer wire has to be contoured so that it follows the surface of the tooth. That’s easier on the facial than the lingual, so a fixed retainer to maintain lower incisor alignment needs to be against the flat portion of the lingual surface, above the rounded cingulum where only one point of contact would be made (Image 2).

If the retainer is made with heavy wire, it should be bonded only on the canines? Why? So the teeth can move relative to each other in function. Remember, you don’t want to splint them so they can’t move in function.

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{{PAGE_138}} So what would be needed if you did want to attach the retainer wire to each incisor? The wire would have to be small and flexible, so that the teeth could still move in function (Image 3). A retainer of that design gives more positive control of the incisors, but has a significant disadvantage: the bond to an incisor can break without the patient knowing it, and then tooth decay under the loose bonding material can develop rapidly. If you’re the dentist seeing a recall patient with a retainer like this, it’s important to check carefully to be sure everything is bonded correctly.

Retention: How? Class I correction: Crowding, crossbite Retention goals: • Maintain alignment Requires two-point contact on teeth.

Image 2: Note that the wire is contoured so that it contacts the flat lingual area above the cingulum, and that it is bonded only to the canines.

Image 3: If each tooth is to be bonded to the retainer wire, it must be light and quite flexible, like this small diameter multi-stranded (twist) wire.

Maintaining Alignment (cont.)

A removable retainer to maintain alignment must satisfy the same requirement: two point contact is required. Note the use of acrylic around the wire in this “clip-on” retainer, so that it fits tightly and compactly against the facial and lingual surfaces of the anterior teeth (Images 1,2). It is so small that it’s lost down the drain if you drop it in the sink. A retainer with this type of anterior component could be extended posteriorly against the lingual surfaces of the premolars and molar, if those teeth had been rotated or otherwise repositioned during treatment (Image 3). That modification also makes it easier to keep up with.

Maxillary fixed or removable retainers would have to meet the same criterion for effectiveness in maintaining alignment: two-point contact on the teeth. It is easier to obtain 2-point contact on the wider facial surface of maxillary incisors with wire than on teeth with more curved or smaller facial

{{PAGE_139}} surfaces. Note in image 4 the modification to place tightly-fitting wires against the facial surface of the canine. For this patient, the maxillary canines had been rotated slightly and moved lingually into position, so it was important to keep them from drifting facially and rotating toward their original orientation.

Another aspect of maintaining alignment is keeping spaces closed or open, as desired. Also in Image 5, note the wires mesial and distal to the small maxillary lateral incisors to keep space open until a restorative dentist can build up the crown width with a composite bonding material.

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{{PAGE_141}} Image 5, Maxillary removable retainer: This maxillary removable retainer has been modified to maintain space mesial and distal to the lateral incisors, using wire segments into the space.

Thermoplastic Retainers

Another possible retainer for maintenance of alignment is a “suckdown” clear plastic device made from a thermoplastic material that was vacuum-formed to fit over the dental arch. As the cost of the equipment to do this dropped in the late 1980s, the Essix company offered it to orthodontists, and retainers of this type became popular. One can be quickly fabricated in the office on a dental cast taken just after the active appliance was removed, so that the patient goes home with a retainer the same day.

Their advantage is that the clear material makes them almost invisible—and this technology was extended to treatment in the development of Invisalign as a treatment method. Most patients like them, especially for the maxillary arch. Although they work in the lower arch, they are less comfortable there, and one thickness of the plastic material between the teeth is more acceptable than two thicknesses. When alignment is the only problem, a maxillary suck-down retainer and a bonded wire or clip-on retainer for the mandibular arch is a good combination.

Keeping Spaces Closed

When teeth are missing and one of the goals of orthodontic treatment is to close space, an important objective of retention is to keep those spaces closed. Note that this patient (Images 1, 2) has had closure of the space of missing laterals, with further space closure on the right side where a second premolar also was missing.

The wrap-around outer bow provides a force to keep the teeth from moving apart, while the acrylic lingual portion provides two-point contact, as does the wire across the flat central incisors. Two-point contact on the facial of the canines, premolars and molars is difficult but unnecessary if the lingual acrylic is configured tightly against that surface.

Another way to keep extraction spaces closed is to solder the outer bow of a removable retainer to clasps on the molar teeth, which extends the bow across a premolar extraction site (Image 3).

Thermoplastic retainers also are a good choice for keeping spaces closed.

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{{PAGE_142}} Image 1, Maxillary wrap-around retainer: The outer bow is activated by closing the loops slightly, so that it provides a light force against the teeth.

Image 2, Wrap-around retainer in the mouth: Note the two-point contact on the lingual and on the facial of the central incisors.

Image 3, Outer bow extended to first molar: To keep a maxillary extraction space closed, the outer bow can be extended posteriorly to the first molar and soldered to the clasp on it.

Retaining a Maxillary Central DiastemaRetaining a Maxillary Central Diastema

A maxillary central diastema poses a special retention problem, because usually there’s a defect in the bone between these teeth that prevents gingival elastic fibers from crossing the midline. The result is that, unlike every other location in the dental arches, there is nothing to keep the teeth together after the central incisors have been brought together.

The solution is a flexible wire bonded on the lingual (Image 1). The space pops open as soon as there is nothing holding the teeth together, so a bonded flexible wire is by far the best retainer. A

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{{PAGE_143}} removable retainer moves the teeth back and forth a little every time it is placed or removed, and that leads to continuing mobility and risks both periodontal breakdown and root resorption.

The wire is contoured to be passive on a dental cast (Image 2). To bond the retainer so that it keeps the space closed, it is necessary to pull the teeth tightly together (Image 3), and then bond it in position (Image 4). A flexible wire allows the teeth to move slightly in function, and is compatible with long-term periodontal health; a heavy stiff wire splints the teeth and prevents movement in function. The flexible wire also is much more likely to remain in place. This is a definite indication for a retainer that will be needed indefinitely.

{{PAGE_144}} Image 1, Maxillary central diastema: A wide separation of the teeth like this usually is due to a cleft in the interdental bone, with excessive fibrous tissue in the area. Image 2, Laboratory preparation: The flexible wire must be formed in the laboratory to be sure that it will fit passively when it is bonded intra-orally. Image 3, Tying teeth together for bonding: If the retainer is bonded before the orthodontic appliance is removed, the brackets on the central incisors can be used to hold the space tightly closed during bonding. If brackets have been removed, a wire ligature can be looped over the crowns to hold the space closed. Image 4, Bonding completed: The flexible wire retainer has two advantages over a heavier wire: it allows better periodontal health and is more likely to be maintained long-term. Image 5: Tying the teeth together while bonding them ensures that they will not move apart during the

{{PAGE_145}} bonding process - a prudent step since a diastema can re-open remarkably quickly.

Maintaining Overbite Correction

Many patients with excessive overjet (the typical Class II division 1) also have a deep bite anteriorly, because the lack of incisor contact allows the lower incisors to over-erupt. For these patients, retaining the overbite correction is as important as keeping the upper incisors in alignment.

How do you retain overbite? If it was due to over-eruption of lower incisors, you block further eruption of those teeth. This requires a bite plate behind the upper incisors. It is easy to contour the anterior palatal portion of an acrylic retainer so that the lower incisors just touch it, and the wire outer bow of the retainer can be activated to keep a light force against the upper incisors. If the overbite was due to over-eruption of the maxillary incisors, a mandibular clip-on retainer can provide a surface that prevents re-eruption after treatment.

For the patient shown in these photos (Images 1 and 2), contact of the incisors with the retainer in the other arch is controlling re-eruption in both arches.

Suck-down retainers are not a good choice for a patient who had excessive overbite, because the light contact of the plastic material with the facial and lingual surfaces of the teeth may not be enough to keep incisors from erupting.

Maintaining Open Bite Correction

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{{PAGE_146}} Anterior open bite usually is due to excessive eruption of maxillary posterior teeth, not to infra-eruption of maxillary incisors. If that is the case, force to oppose eruption of those teeth would be an important component of a retainer.

The easiest way to generate such a force is to extend the acrylic of a maxillary retainer over the occlusal surface (Image 1), so that the mandible is forced downward a little more than the freeway space (Image 2). So the retainer should look as if it makes the open bite worse? In a word, yes. It may be counter-intuitive but it does give control of posterior eruption.

This can be effective for mild open bite problems, but not for patients with a severe long face / open bite growth pattern. As we have noted, those patients may require re-treatment after growth stops.

Maintaining Class I Occlusion

As we have noted, after correction of a skeletal Class II problem, growth in the original pattern of more maxillary than mandibular growth can recreate the malocclusion. That’s why treatment should end at about the time adolescent growth subsides to the very slow levels of adult life.

How do you retain an occlusal relationship? For Class II patients, a functional appliance like the one shown here is the best way to do that. Think about it: this appliance, into which the patient bites into a predetermined position, is rather like maxillary and mandibular retainers bonded together. If the Class II patient is still growing, it makes no sense to have retainers that maintain alignment and tooth position in each arch but do not retain the occlusal relationship. From the patient’s point of view, wearing retainers that are joined together is not appreciably different from wearing separate upper and lower retainers, and they need to wear it only at night. An appliance like this during the last part

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{{PAGE_147}} of post-treatment growth is the only way to keep some patients from slipping back toward Class II. It isn’t exactly active treatment, it’s just a way to control an unfortunate growth pattern. For mandibular prognathic Class III patients, unfortunately, this doesn’t work. We have already discussed the difficulty of controlling that growth pattern. Like severe open bite patients, re-treatment after mandibular growth subsides in the late teens, is required, and orthognathic surgery may be the best treatment.

Summary How is retention accomplished? With procedures aimed at the specific problem(s) of individual patients: Alignment: successful appliances include • vacuum-formed thermoplastic “suck-down” retainer • maxillary palate-covering retainers with wire outer bow (Hawley retainer) • mandibular clip-on retainers with wire-reinforced plastic in contact with the teeth • mandibular lingual bonded wires • heavy wire, bonded only to canines • light wire, bonded to each tooth • maxillary lingual light wires, bonded to central incisors only or centrals and laterals Space closure: • wrap-around facial wire

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• wire soldered to molar clasps
• suck-down retainer Deep bite: contact with surface of retainer in other arch Anterior open bite: occlusal coverage posteriorly Class II: modified functional appliance

Referral to Self-test

At this point, review the assigned reading for this module (Chapter 18, pages 606-616, Contemporary Orthodontics, 5th edition; Chapter 17, pages 617-628, 4th edition). Then take the self-test and use it to direct your re-examination of parts of the teaching module and the reading.

Copyright 2013, UNC Department of Orthodontics.

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