**DMD Level 2**
**Unit B: Diagnostic Procedures**
Orthodontic Seminar
- Part 1. Dentofacial Proportions
- Part 2. Principles of Cephalometric Analysis
- Part 3. Space Analysis
- Part 4. Systematic Description of Malocclusion
1
#### Academic Level and Unit
- DMD Level 2
- Unit B: Diagnostic Procedures
#### Seminar Curriculum
1. Part 1: Dentofacial Proportions
2. Part 2: Principles of Cephalometric Analysis
3. Part 3: Space Analysis
4. Part 4: Systematic Description of Malocclusion
**Part 1. Dentofacial Proportions**
Be sure that you are able to:
1. **Describe** ideal dentofacial proportions from the full face aspect, indicating the role of symmetry and the relationship of the width of upper to lower face characteristics.
2. **Describe** ideal dentofacial proportions from the lateral aspect, indicating the a-p and vertical relationships of the upper, mid and lower face.
3. **Describe** the method and objectives of facial form analysis.
4. **Discuss** the limitations of facial form analysis.
5. **Carry out** a facial form analysis.
The University of Western Australia
**Part 1. Dentofacial Proportions**
Upon completion of this section, you should be able to:
1. **Describe** ideal dentofacial proportions from the full face aspect, indicating the role of symmetry and the relationship of the width of upper to lower face characteristics.
2. **Describe** ideal dentofacial proportions from the lateral aspect, indicating the a-p and vertical relationships of the upper, mid and lower face.
3. **Describe** the method and objectives of facial form analysis.
4. **Discuss** the limitations of facial form analysis.
5. **Carry out** a facial form analysis.
1. Describe ideal dentofacial proportions from the full face aspect, indicating the role of symmetry and the relationship of the width of upper to lower face characteristics.
**1. Describing Ideal Dentofacial Proportions (Full Face, Symmetry & Vertical Relationships)**
The slide indicates three ideal vertical relationships (white line indicating the logical face) and three proportional relationships between the upper and lower face width characteristics. The image targets should be to be examined in order to assess the rotation of the surface, or rather the tilt and lie of the face.
The second relationship is the third part of the face: the relationships between the skull, the orbits, the nasal bone, the chin (mental plane), the submental plane.
#### Vertical and Proportional Relationships
Ideal facial proportions are assessed through specific vertical and width relationships:
- **Vertical Divisions**: There are three ideal vertical relationships used to define the logical face.
- **Width Characteristics**: Three proportional relationships exist between the upper and lower face widths.
- **Surface Assessment**: Evaluation should target the rotation, tilt, and lie of the face.
#### Anatomical Landmarks
The analysis involves examining the relationships between the following structures:
- The skull
- The orbits
- The nasal bone
- The chin (mental plane)
- The submental plane
![]()
Clinical photograph demonstrating ideal vertical facial proportions. The image shows a full-face view of a female subject with sunglasses covering the eyes. Red horizontal lines divide the face into three equal segments (labeled '1/3'), marking the hairline to eyebrows, eyebrows to subnasale, and subnasale to chin.
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Clinical photograph demonstrating ideal mid-facial symmetry. A central vertical red line runs down the nose, intersecting with horizontal dotted lines at key anatomical landmarks: glabella, nasal root, subnasale, and soft tissue pogonion. Sunglasses obscure the eyes.
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Clinical photograph demonstrating proportional relationships between upper and lower face widths. A central vertical red line marks the midline. Horizontal red lines indicate the width of the maxilla (upper jaw) relative to the mandible (lower jaw), illustrating the relationship between these characteristics.
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Clinical photograph demonstrating ideal facial thirds (horizontal division). Vertical red lines are superimposed on the face, dividing it into left and right halves to assess symmetry across the midline.
2. Describe ideal dentofacial proportions from
the lateral aspect, indicating the a-p and vertical
relationships of the upper, mid and lower face.
- **1/3**
- **1/3**
- **1/3**
**NOT > 6MM**
**THE UNIVERSITY OF**
**WESTERN**
**AUSTRALIA**
4
#### Vertical Proportions
The lateral aspect of the face is ideally divided into equal thirds:
- Upper third
- Middle third
- Lower third
#### Anteroposterior Relationships
- A-P discrepancy should not exceed 6mm.
![]()
A composite image showing three lateral profile photographs of individuals used to illustrate ideal dentofacial proportions. The left panel shows a subject with a balanced profile. The center panel highlights vertical facial thirds (labeled '1/3') from the hairline to the nose bridge, nose base to chin, and chin to neck. The right panel illustrates the anterior-posterior relationship of the lips relative to the mandibular plane, with an annotation indicating this distance should be 'NOT > 6MM'.
2. Describe ideal dentofacial proportions from the lateral aspect, indicating the a-p and vertical relationships of the upper, mid and lower face.
### Long face height
### Short face height
5
#### Vertical Height Variations
- **Long face height**: An increase in the vertical dimension of the lower face.
- **Short face height**: A decrease in the vertical dimension of the lower face.
![]()
Clinical lateral photograph of a patient demonstrating long face height. The image shows the side profile of a young person with short reddish-brown hair. A black digital mask obscures the eyes. The facial features exhibit vertical elongation, consistent with the caption indicating 'Long face height'.
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Clinical lateral photograph of a patient demonstrating short face height. The image shows the side profile of an adult male with receding hairline and thinning gray hair. A black digital mask obscures the eyes. The facial structure appears vertically compressed compared to the standard proportions implied by the context.
3. Describe the method and objectives of facial form analysis.
6
Describe the method and objectives of facial form analysis.
**4. Discuss the limitations of facial form analysis.**
• Soft tissue variation
• Ethnicity
#### Analysis Constraints
Limitations of facial form analysis include:
- Soft tissue variation
- Ethnicity
# 5. Carry out a facial form analysis
8
Carry out a facial form analysis.
# Part 2. Principles of Cephalometric Analysis
**THE UNIVERSITY OF WESTERN AUSTRALIA**
## Be sure that you are able to:
1. Discuss the background for the development of cephalometric radiography in orthodontics.
2. Identify the two major uses of cephalometric radiographs in orthodontics.
3. Given a cephalometric radiograph, identify and trace landmarks necessary to properly outline and evaluate the position of (a) cranial base, (b) skeletal maxilla, (c) maxillary dentition, (d) skeletal mandible and (e) mandibular dentition.
4. Given a cephalometric tracing, evaluate whether the incisor teeth are retrusive, positioned properly or protrusive relative to their supporting bone.
5. Given a cephalometric tracing, evaluate the antero-posterior and vertical relationships of the jaws to the cranial base and to each other.
6. Compare and contrast the measurement analysis and template analysis methods of evaluating cephalometric radiographs.
7. Given an initial and progress or final cephalometric tracing, complete an overall superimposition and maxillary and mandibular superimpositions, producing a composite tracing.
8. Given a composite cephalometric tracing, describe the changes evident in the tracing and relate them to growth or treatment.
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#### Learning Objectives
Upon completion of this section, you should be able to:
1. Discuss the background for the development of cephalometric radiography in orthodontics.
2. Identify the two major uses of cephalometric radiographs in orthodontics.
3. Given a cephalometric radiograph, identify and trace landmarks necessary to properly outline and evaluate the position of:
- (a) cranial base
- (b) skeletal maxilla
- (c) maxillary dentition
- (d) skeletal mandible
- (e) mandibular dentition
4. Given a cephalometric tracing, evaluate whether the incisor teeth are retrusive, positioned properly or protrusive relative to their supporting bone.
5. Given a cephalometric tracing, evaluate the antero-posterior and vertical relationships of the jaws to the cranial base and to each other.
6. Compare and contrast the measurement analysis and template analysis methods of evaluating cephalometric radiographs.
7. Given an initial and progress or final cephalometric tracing, complete an overall superimposition and maxillary and mandibular superimpositions, producing a composite tracing.
8. Given a composite cephalometric tracing, describe the changes evident in the tracing and relate them to growth or treatment.
1. Discuss the background for the development
of cephalometric radiography in orthodontics.
**THE UNIVERSITY OF WESTERN AUSTRALIA**
Discuss the background for the development of cephalometric radiography in orthodontics.
![]()
Historical black and white photo showing an early orthodontic radiographic apparatus with a patient's head positioned on a horizontal bar extending from a vertical support structure.
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Composite figure containing two diagrams illustrating Van Loon's cephalometric method. The top diagram shows a profile view of a skull inside a box-like frame, while the bottom diagram shows a similar setup but with the X-ray beam angled differently to capture a different projection of the craniofacial structures.
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Historical black and white photo depicting a clinical setting with a patient seated in a dental chair, surrounded by vintage medical equipment including a tall columnar device and other machinery used for cephalometric radiography.
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Modern color photo showing a side-profile view of a patient undergoing cephalometric radiography using a contemporary cephalostat machine, which holds the patient's head in place for standardized imaging.
2. **Identify the two major uses of cephalometric radiographs in orthodontics**.
* Diagnosis
* Growth and treatment effects
#### Primary Applications
The two major uses of cephalometric radiographs in orthodontics are:
- Diagnosis
- Growth and treatment effects
![]()
Lateral cephalometric tracing diagram on a tan background. The image displays superimposed wireframe tracings of a human skull profile in multiple colors (yellow, blue, red) representing different time points or subjects. A legend at the top left labeled 'Age' shows three colored dots corresponding to ages 7, 10, and 13. Black arrowheads point towards the jawline areas, and text at the bottom reads 'Normal Direction', indicating the direction of growth or alignment being analyzed.
3. Given a cephalometric radiograph, identify and trace
landmarks necessary to properly outline and evaluate the
position of (a) cranial base, (b) skeletal maxilla, (c) maxillary
dentition, (d) skeletal mandible and (e) mandibular dentition.
**THE UNIVERSITY OF WESTERN AUSTRALIA**
12
Given a cephalometric radiograph, identify and trace landmarks necessary to properly outline and evaluate the position of (a) cranial base, (b) skeletal maxilla, (c) maxillary dentition, (d) skeletal mandible and (e) mandibular dentition.
![]()
Lateral cephalometric tracing diagram showing skeletal and dental landmarks. Visible labels include: N (Nasion), S (Sella), Po (Porion), Or (Orbitale), A (Subspinale), B (Supramentale), Pg (Pogonion), M (Menton). The image outlines the cranial base, maxilla, mandible, and dentition with light blue lines on a dark blue background.
4. Given a cephalometric tracing, evaluate whether the incisor teeth are retrusive, positioned properly or protrusive relative to their supporting bone.
# Upper Incisor
* 1-NA
* 1-NA (mm)
* 1-ANS-PNS
#### Upper Incisor Evaluation
To evaluate whether the incisor teeth are retrusive, positioned properly, or protrusive relative to their supporting bone, the following measurements are used:
- 1-NA
- 1-NA (mm)
- 1-ANS-PNS
![]()
Lateral cephalometric tracing diagram showing the upper incisor position relative to skeletal landmarks. The image includes a green line representing the upper incisor axis and a yellow vertical line likely indicating a reference plane (possibly N-A or perpendicular to S-N). Labels include 'Upper Incisor' pointing to the anterior teeth region, with measurement annotations such as '1-NA', '1-NA (mm)', and '1-ANS-PNS' visible in a box on the right side. Blue arrows indicate rotational movement of the maxilla and mandible.
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Lateral cephalometric tracing diagram of the lower jaw and skull. The image features a side profile outline with overlaid diagnostic lines (yellow vertical, green diagonal) and red arrows indicating specific measurements. A yellow box on the right lists measurement parameters: '1-NB', '1-NB (mm)', '1-MP', and '1-Apog (mm)'.
4. Given a cephalometric tracing, evaluate whether the incisor teeth are retrusive, positioned properly or protrusive relative to their supporting bone.
**Upper-Lower Incisor**
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#### Upper-Lower Incisor Relationship
Evaluate whether the incisor teeth are retrusive, positioned properly, or protrusive relative to their supporting bone.
![]()
Cephalometric tracing diagram showing a lateral skull profile with superimposed lines and annotations. The blue line represents the upper incisor position relative to the maxilla, while the green line indicates the lower incisor position relative to the mandible. Arrows and text labels are used to highlight specific anatomical landmarks and measurements relevant to evaluating incisor positioning.
5. Given a cephalometric tracing, evaluate the antero-posterior and vertical relationships of the jaws to the cranial base and to each other.
**Cranial Base-maxilla-mandible**
horizontal
SN
**H-NA**
**SN-H**
**SN-A**
**SN-B**
**ANB**
**SN-Pog**
**A-B Dist**
**SN length**
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#### Horizontal Skeletal Relationships
Evaluation of the antero-posterior relationships of the jaws to the cranial base and to each other using the following parameters:
- SN (Sella-Nasion)
- H-NA
- SN-H
- SN-A
- SN-B
- ANB
- SN-Pog
- A-B Dist
- SN length
![]()
Labeled cephalometric tracing diagram illustrating cranial base-maxilla-mandible relationships. The image includes a lateral skull outline with overlaid anatomical landmarks and measurement lines: a red horizontal reference line labeled 'horizontal', a blue arrow indicating antero-posterior dimension, yellow and green vertical lines for angular measurements, and dashed red lines for vertical references. Labels such as SN (Sella-Nasion), H-NA, SN-H, SN-A, SN-B, ANB, SN-Pog, A-B Dist, and SN length are positioned to indicate specific cephalometric angles and distances used in evaluating jaw relationships.
**5.** Given a cephalometric tracing, evaluate the antero-posterior and vertical relationships of the jaws to the cranial base and to each other.
**Wits**
#### Wits Appraisal
Evaluate the antero-posterior and vertical relationships of the jaws to the cranial base and to each other using the Wits analysis.
![]()
Cephalometric tracing diagram illustrating the Wits appraisal. The image features a lateral skull profile outline in blue lines. A red line connects point A (anterior nasal spine) to point B (posterior aspect of the mandibular symphysis), representing the occlusal plane. Two yellow lines are drawn perpendicular to this red reference line, extending from the incisal edges of the upper and lower central incisors. This visual demonstrates how to measure the antero-posterior discrepancy between the jaws.
5. **Given a cephalometric tracing, evaluate the antero-posterior and vertical relationships of the jaws to the cranial base and to each other.**
**Vertical**
| Parameter | Definition |
|---|---|
| MX-H | Gunderson's Horizontal reference plane |
| MX-MP | Maxillary Mandle arch reference plane |
| SN-MP | Cranium to Elbow reference plane |
| OP-SN | Hyoid to Mandible reference plane |
| OP-MP | Hyoid to Ears reference plane |
| SGn-FH | Hyoid to Mandible reference plane |
#### Vertical Skeletal Relationships
| Parameter | Definition |
| :--- | :--- |
| MX-H | Gunderson's Horizontal reference plane |
| MX-MP | Maxillary Mandle arch reference plane |
| SN-MP | Cranium to Elbow reference plane |
| OP-SN | Hyoid to Mandible reference plane |
| OP-MP | Hyoid to Ears reference plane |
| SGn-FH | Hyoid to Mandible reference plane |
![]()
Lateral cephalometric tracing diagram illustrating vertical reference planes. The image features a skeletal profile of the head and neck overlaid with several colored lines representing different anatomical measurements: a blue horizontal line (MX-H), a green slightly inclined line (SN-MP), a yellow horizontal line (MX-MP), a pink horizontal line (OP-SN), a red downward-sloping line (OP-MP), and a light blue oblique line (SGn-FH). A dashed cyan line runs vertically through the mid-face structure. A legend box in the bottom right corner lists the abbreviations for these parameters: MX-H, MX-MP, SN-MP, OP-SN, OP-MP, SGn-FH.
**Facial Height/Depth**
**LFH-TotFH**
**Nart-TotFH**
**NS-TotFH**
**5. Given a cephalometric tracing, evaluate the antero-posterior and vertical relationships of the jaws to the cranial base and to each other.**
**The University of Western Australia**
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#### Facial Height and Depth
Evaluate the vertical relationships of the jaws using the following ratios and measurements:
- LFH-TotFH
- Nart-TotFH
- NS-TotFH
![]()
Lateral cephalometric tracing diagram illustrating Facial Height/Depth measurements. The image features a blue line drawing of the skull profile with superimposed measurement lines and arrows: two yellow horizontal arrows indicate antero-posterior jaw relationships, while vertical red and yellow arrows denote vertical facial height segments. A text box on the right lists three specific measurements: LFH-TotFH, Nart-TotFH, and NS-TotFH. The diagram serves to visually demonstrate how these dimensions are evaluated relative to the cranial base.
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Lateral cephalometric diagram illustrating facial height and depth measurements. The image includes a line drawing of the skull and facial skeleton with annotations: yellow arrows indicating horizontal depth measurements (likely SNA/SNB or similar), red and yellow vertical lines indicating total facial height landmarks, and a text box listing abbreviations LFH-TotFH, Nart-TotFH, NS-TotFH.
6. **Compare and contrast the measurement analysis and template analysis methods of evaluating cephalometric radiographs.**
**Cranial Base-maxilla-mandible**
horizontal
SN
H-NA
SN-H
SN-A
SN-B
ANB
SN-Pog
A-B Dist
**SN length**
#### Measurement and Template Analysis Comparison
Compare and contrast the measurement analysis and template analysis methods. Key horizontal parameters for evaluation include:
- SN
- H-NA
- SN-H
- SN-A
- SN-B
- ANB
- SN-Pog
- A-B Dist
- SN length
![]()
Labelled diagram showing a lateral cephalometric radiograph analysis. The image displays a skeletal profile with superimposed lines and measurement points. Key annotations include 'horizontal' (red line), 'SN' (Sella-Nasion line), and specific angular/linear measurements listed in a yellow box: H-NA, SN-H, SN-A, SN-B, ANB, SN-Pog, A-B Dist, and SN length.
![]()
Figure displaying a template analysis of a cephalogram. It shows a wireframe outline of the head and neck overlaid on a grid system, representing the geometric tracing used in template-based evaluation methods.
The University of Western Australia
PENNY LANE
INITIAL 3-1-53
FINAL 2-24-56
D.O.B. 1-7-42
7. Given an initial and progress or final cephalometric tracing, complete an overall superimposition and maxillary and mandibular superimpositions, producing a composite tracing.
#### Case Study: Penny Lane
- **Initial:** 3-1-53
- **Final:** 2-24-56
- **D.O.B.:** 1-7-42
Complete an overall superimposition and maxillary and mandibular superimpositions to produce a composite tracing.
![]()
Cephalometric composite tracing diagram. The image displays a side profile of a skull with superimposed anatomical structures in white and red lines against a blue background. Visible labels include 'PENNY LANE', 'INITIAL 3-1-53', 'FINAL 2-24-56', and 'D.O.B. 1-7-42' at the bottom left.
**8. Given a composite cephalometric tracing, describe the changes evident in the tracing and relate them to growth or treatment.**
Penny Lane
Initial 3-1-53
Final 2-29-56
D.O.B. 1-7-42
#### Growth and Treatment Evaluation
**Patient:** Penny Lane
- **Initial:** 3-1-53
- **Final:** 2-29-56
- **D.O.B.:** 1-7-42
Describe the changes evident in the composite cephalometric tracing and relate them to growth or treatment.
![]()
Composite cephalometric tracing showing a side-profile view of the skull and teeth. Two outlines are superimposed: a white line representing the initial state (dated 3-1-53) and a red line representing the final state (dated 2-29-56). The tracings depict anatomical landmarks including the nasal bone, maxilla, mandible, and dentition. A comparison of the two lines reveals changes in the position of the jaws and teeth over the three-year period. Text at the bottom left identifies the subject as 'Penny Lane', with birth date 1-7-42.
**Part 3. Space Analysis**
**THE UNIVERSITY OF WESTERN AUSTRALIA**
Be sure that you are able to:
1. Identify the four major assumptions about growth and development on which space analysis is based.
2. Discuss the rationale for expecting decreased accuracy of space analysis in children who do not have a Class I jaw relationship.
3. Identify the diagnostic materials needed to perform a space analysis.
4. Carry out a space analysis, as described in Laboratory exercise 2.
5. Indicate how you would interpret a space analysis result in a child whose facial form or cephalometric analysis indicated that the incisors were retrusive or protrusive.
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#### Learning Objectives
Upon completion of this section, you should be able to:
1. Identify the four major assumptions about growth and development on which space analysis is based.
2. Discuss the rationale for expecting decreased accuracy of space analysis in children who do not have a Class I jaw relationship.
3. Identify the diagnostic materials needed to perform a space analysis.
4. Carry out a space analysis, as described in Laboratory exercise 2.
5. Indicate how you would interpret a space analysis result in a child whose facial form or cephalometric analysis indicated that the incisors were retrusive or protrusive.
**1. Identify the four major assumptions about growth and development on which space analysis is based.**
1. Identify the four major assumptions about growth and development on which space analysis is based.
**2. Discuss the rationale for expecting decreased accuracy of space analysis in children who do not have a Class I jaw relationship.**
2. Discuss the rationale for expecting decreased accuracy of space analysis in children who do not have a Class I jaw relationship.
![]()
Radiographic diagram showing a lateral cephalometric tracing of a child's dentition. The image illustrates the 'Normal Pattern' of mixed dentition eruption and space maintenance. It displays outlines of primary teeth (labeled 1-4) and developing permanent successors (labeled 1-4). Red arrows point to the anterior segment, indicating no significant change in the antero-posterior position of the incisors. A scale bar labeled '5cm' is present at the bottom.
The University of Western Australia
Forward rotation
Vertical condylar growth
Think of soft tissue moulding
3433i ♂
#### Growth and Soft Tissue Considerations
- Forward rotation
- Vertical condylar growth
- Soft tissue moulding
![]()
Lateral cephalometric radiograph diagram showing a skeletal profile with superimposed outlines. The image displays the mandible and maxilla in side view, highlighting dental occlusion. Several points are labeled on the lower jaw: Point 1 at the gonion (angle of the mandible), Point 2 near the ramus/condyle area, Point 3 near the molars, and Point 4 near the condylar region. There is a dashed line indicating a horizontal reference plane. A scale bar at the bottom indicates '5 cm'. The text '3433i ♂' appears to the right of the chin, likely identifying the patient case. This visual demonstrates anatomical landmarks relevant to orthodontic analysis.
![]()
Lateral cephalometric radiograph (Figure) showing a side view of the skull, jaw, and teeth. The image displays superimposed outlines: solid white lines represent the current position of anatomical structures, while dashed white lines indicate a previous position or growth change. Visible labels include '3' pointing to the mandibular condyle area and '2' near the mandibular symphysis. Text annotations in the upper right corner describe the findings as 'Backward rotation', 'Horizontal condylar growth', and suggest to 'Think of soft tissue moulding'. A patient ID number '7176i♀' is visible at the bottom right.
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Clinical profile photograph of a young male patient's head and neck. The image displays the right side of the face in lateral view, showing short dark hair, an ear, and the mandible. The subject appears to be demonstrating a facial asymmetry or deformity of the jaw, with the chin positioned significantly posteriorly relative to the maxilla (retrognathia).
![]()
Lateral cephalometric radiograph (X-ray) of a human skull in profile. The image displays the cranium, cervical spine, and maxillofacial structures including the nasal cavity and mandible. A red arrow points specifically to the lower anterior region of the jaw, indicating the position or alignment of the lower incisors relative to the chin and upper lip. The text overlay 'Lower teeth compensated' describes the specific orthodontic condition illustrated by the skeletal relationship shown.
![]()
Profile photograph of a person with brown hair styled in a shag or mullet cut, featuring short sides and longer bangs. The subject is wearing a plaid shirt.
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Lateral radiograph (X-ray) of the cervical spine and mandible. The image displays the C-spine alignment, the base of the skull, and the mandibular ramus and body in profile.
**3. Identify the diagnostic materials needed to perform a space analysis.**
**The University of Western Australia**
3. Identify the diagnostic materials needed to perform a space analysis.
![]()
Clinical photograph of dental study models (casts) showing the upper and lower arches. The image demonstrates a Class II malocclusion with an anterior crossbite on the right side, where the maxillary teeth are positioned lingual to the mandibular teeth.
![]()
Cephalometric profile radiograph or clinical photograph of a patient in lateral view. The image shows the facial profile and head posture necessary for cephalometric analysis to evaluate skeletal relationships and soft tissue proportions.
4. Carry out a space analysis, as described in Laboratory exercise 2.
The University of Western Australia
• To be done in laboratory exercise 2
34
4. Carry out a space analysis, as described in Laboratory exercise 2.
- To be done in laboratory exercise 2
5. Indicate how you would interpret a space analysis result in a child whose facial form or cephalometric analysis indicated that the incisors were retrusive or protrusive.
35
5. Indicate how you would interpret a space analysis result in a child whose facial form or cephalometric analysis indicated that the incisors were retrusive or protrusive.
Part 4. Systematic Description of Malocclusion
Be sure that you are able to:
1. Identify the five major characteristics of malocclusion on which systematic description is based.
2. Discuss the rationale for considering incisor crowding and incisor protrusion as being two aspects of the same thing.
3. Describe how a skeletal posterior crossbite can be differentiated from a dental crossbite.
4. Describe how a skeletal Class II or Class III malocclusion can be differentiated from a dental Class II or Class III.
5. Describe the cephalometric characteristics of a skeletal open bite and a skeletal deep bite.
6. Indicate how you would distinguish a dental anterior open bite from a skeletal open bite.
36
#### Learning Objectives
Upon completion of this section, you should be able to:
1. Identify the five major characteristics of malocclusion on which systematic description is based.
2. Discuss the rationale for considering incisor crowding and incisor protrusion as being two aspects of the same thing.
3. Describe how a skeletal posterior crossbite can be differentiated from a dental crossbite.
4. Describe how a skeletal Class II or Class III malocclusion can be differentiated from a dental Class II or Class III.
5. Describe the cephalometric characteristics of a skeletal open bite and a skeletal deep bite.
6. Indicate how you would distinguish a dental anterior open bite from a skeletal open bite.
1. Identify the five major characteristics of malocclusion on which systematic description is based.
```mermaid
graph TD
A[Relation to line of occlusion / arch length?] --> B(DENTO-FACIAL PROTRUSION?)
B --> C{TRANSVERSE RELATIONSHIPS}
B --> D{A-P RELATIONSHIPS}
B --> E{VERTICAL RELATIONSHIPS}
C --- C1[SKELETAL]
C --- C2[DENTAL]
D --- D1[SKELETAL]
D --- D2[DENTAL]
E --- E1[SKELETAL]
E --- E2[DENTAL]
```
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#### Systematic Description Framework
The systematic description of malocclusion is based on the following diagnostic considerations:
- **Arch Length and Alignment**: Relation to the line of occlusion.
- **Dento-facial Protrusion**: Assessment of the profile and incisor position.
- **Transverse Relationships**: Differentiation between skeletal and dental components.
- **Anteroposterior (A-P) Relationships**: Differentiation between skeletal and dental components.
- **Vertical Relationships**: Differentiation between skeletal and dental components.
![]()
Venn diagram illustrating the five major characteristics of malocclusion used for systematic description. The diagram consists of three intersecting circles labeled 'TRANSVERSE RELATIONSHIPS', 'A-P RELATIONSHIPS', and 'VERTICAL RELATIONSHIPS'. Inside each circle are sub-labels 'SKELETAL' and 'DENTAL'. These three circles are enclosed within a larger oval labeled 'DENTO-FACIAL PROTRUSION?'. Additional text labels 'Relation to line of occlusion' and 'arch length?' appear above the circles.
2. Discuss the rationale for considering incisor crowding and incisor protrusion as being two aspects of the same thing.
Discuss the rationale for considering incisor crowding and incisor protrusion as being two aspects of the same thing.
![]()
Clinical photograph of dental study models (casts) showing the occlusal view of both maxillary and mandibular arches. The left side displays the upper arch with a label 'O-2069', while the right side shows the lower arch. Both arches exhibit significant anterior crowding of the incisors and canines, visually demonstrating the subject matter discussed in the OCR text regarding incisor crowding and protrusion.
2. Discuss the rationale for considering incisor crowding and incisor protrusion as being two aspects of the same thing.
39
Discuss the rationale for considering incisor crowding and incisor protrusion as being two aspects of the same thing.
![]()
Clinical profile photograph of a young child demonstrating severe dental malocclusion. The image shows the side view of the face with lips closed. The primary visual finding is significant anterior open bite and incisor protrusion (bimaxillary protrusion). The lower lip is visibly pushed over the lower incisors, indicating the teeth are positioned outside the normal skeletal boundary. The context from OCR suggests this photo illustrates the relationship between crowding and protrusion.
### Differentiating Skeletal Posterior Crossbite from Dental Crossbite
#### 1. Dental Crossbite
- **Normal width of the maxilla**
- **Maxillary teeth leaning lingually**
#### 2. Skeletal Crossbite
- **Narrow maxilla**
- **Narrow palatal vault**
- **Maxillary teeth leaning facially**
#### Dental Crossbite Characteristics
- Normal width of the maxilla
- Maxillary teeth leaning lingually
#### Skeletal Crossbite Characteristics
- Narrow maxilla
- Narrow palatal vault
- Maxillary teeth leaning facially
![]()
A comparative diagram illustrating palatal width in dental versus skeletal crossbite. The top panel shows a normal-width maxilla with teeth leaning lingually (labeled 'AB' for palatal width and 'CD' for inter-canine distance). The bottom panel depicts a narrow maxilla with a narrow palatal vault and teeth leaning facially, also labeled with 'AB' and 'CD'. This visual supports the differentiation between dental and skeletal posterior crossbite based on maxillary width and tooth inclination.
The University of Western Australia
4. Describe how a skeletal Class II or Class III malocclusion can be differentiated from a dental Class II or Class III.
41
Describe how a skeletal Class II or Class III malocclusion can be differentiated from a dental Class II or Class III.
![]()
Clinical profile photograph of a female patient with blonde hair tied back in a bun. The image shows the side view of the face and head, used to demonstrate facial skeletal features.
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Line drawing diagram representing a lateral cephalometric radiograph (skeletal X-ray) of the same profile. It outlines the craniofacial skeleton, including the cranium, mandible, maxilla, cervical spine, and teeth alignment, intended for comparison with the clinical photo to differentiate skeletal from dental malocclusion.
5. Describe the cephalometric characteristics of a skeletal open bite and a skeletal deep bite.
42
Describe the cephalometric characteristics of a skeletal open bite and a skeletal deep bite.
![]()
Lateral cephalometric tracing (radiograph) showing a skeletal open bite. The upper and lower jaws are depicted with a significant vertical gap between the anterior teeth when in occlusion.
![]()
Lateral cephalometric tracing (radiograph) showing a skeletal deep bite. The mandible is positioned significantly inferior to the maxilla, resulting in an excessive vertical overlap of the incisors.
**6. Indicate how you would distinguish a dental
anterior open bite from a skeletal open bite.**
• Facial height
• Lip competence
• Tooth display
• Cephalometric characteristics
#### Distinguishing Dental Anterior Open Bite from Skeletal Open Bite
To distinguish between dental and skeletal open bites, evaluate the following factors:
- Facial height
- Lip competence
- Tooth display
- Cephalometric characteristics
[^1]: Original PDF page 1: [[DMD Level II UnitB.pdf#page=1|DMD Level II UnitB, p.1]]
[^2]: Original PDF page 2: [[DMD Level II UnitB.pdf#page=2|DMD Level II UnitB, p.2]]
[^3]: Original PDF page 3: [[DMD Level II UnitB.pdf#page=3|DMD Level II UnitB, p.3]]
[^4]: Original PDF page 4: [[DMD Level II UnitB.pdf#page=4|DMD Level II UnitB, p.4]]
[^5]: Original PDF page 5: [[DMD Level II UnitB.pdf#page=5|DMD Level II UnitB, p.5]]
[^6]: Original PDF page 6: [[DMD Level II UnitB.pdf#page=6|DMD Level II UnitB, p.6]]
[^7]: Original PDF page 7: [[DMD Level II UnitB.pdf#page=7|DMD Level II UnitB, p.7]]
[^8]: Original PDF page 8: [[DMD Level II UnitB.pdf#page=8|DMD Level II UnitB, p.8]]
[^9]: Original PDF page 9: [[DMD Level II UnitB.pdf#page=9|DMD Level II UnitB, p.9]]
[^10]: Original PDF page 10: [[DMD Level II UnitB.pdf#page=10|DMD Level II UnitB, p.10]]
[^11]: Original PDF page 11: [[DMD Level II UnitB.pdf#page=11|DMD Level II UnitB, p.11]]
[^12]: Original PDF page 12: [[DMD Level II UnitB.pdf#page=12|DMD Level II UnitB, p.12]]
[^13]: Original PDF page 13: [[DMD Level II UnitB.pdf#page=13|DMD Level II UnitB, p.13]]
[^14]: Original PDF page 14: [[DMD Level II UnitB.pdf#page=14|DMD Level II UnitB, p.14]]
[^15]: Original PDF page 15: [[DMD Level II UnitB.pdf#page=15|DMD Level II UnitB, p.15]]
[^16]: Original PDF page 16: [[DMD Level II UnitB.pdf#page=16|DMD Level II UnitB, p.16]]
[^17]: Original PDF page 17: [[DMD Level II UnitB.pdf#page=17|DMD Level II UnitB, p.17]]
[^18]: Original PDF page 18: [[DMD Level II UnitB.pdf#page=18|DMD Level II UnitB, p.18]]
[^19]: Original PDF page 19: [[DMD Level II UnitB.pdf#page=19|DMD Level II UnitB, p.19]]
[^20]: Original PDF page 20: [[DMD Level II UnitB.pdf#page=20|DMD Level II UnitB, p.20]]
[^21]: Original PDF page 21: [[DMD Level II UnitB.pdf#page=21|DMD Level II UnitB, p.21]]
[^22]: Original PDF page 22: [[DMD Level II UnitB.pdf#page=22|DMD Level II UnitB, p.22]]
[^23]: Original PDF page 23: [[DMD Level II UnitB.pdf#page=23|DMD Level II UnitB, p.23]]
[^24]: Original PDF page 24: [[DMD Level II UnitB.pdf#page=24|DMD Level II UnitB, p.24]]
[^25]: Original PDF page 25: [[DMD Level II UnitB.pdf#page=25|DMD Level II UnitB, p.25]]
[^26]: Original PDF page 26: [[DMD Level II UnitB.pdf#page=26|DMD Level II UnitB, p.26]]
[^27]: Original PDF page 27: [[DMD Level II UnitB.pdf#page=27|DMD Level II UnitB, p.27]]
[^28]: Original PDF page 28: [[DMD Level II UnitB.pdf#page=28|DMD Level II UnitB, p.28]]
[^29]: Original PDF page 29: [[DMD Level II UnitB.pdf#page=29|DMD Level II UnitB, p.29]]
[^30]: Original PDF page 30: [[DMD Level II UnitB.pdf#page=30|DMD Level II UnitB, p.30]]
[^31]: Original PDF page 31: [[DMD Level II UnitB.pdf#page=31|DMD Level II UnitB, p.31]]
[^32]: Original PDF page 32: [[DMD Level II UnitB.pdf#page=32|DMD Level II UnitB, p.32]]
[^33]: Original PDF page 33: [[DMD Level II UnitB.pdf#page=33|DMD Level II UnitB, p.33]]
[^34]: Original PDF page 34: [[DMD Level II UnitB.pdf#page=34|DMD Level II UnitB, p.34]]
[^35]: Original PDF page 35: [[DMD Level II UnitB.pdf#page=35|DMD Level II UnitB, p.35]]
[^36]: Original PDF page 36: [[DMD Level II UnitB.pdf#page=36|DMD Level II UnitB, p.36]]
[^37]: Original PDF page 37: [[DMD Level II UnitB.pdf#page=37|DMD Level II UnitB, p.37]]
[^38]: Original PDF page 38: [[DMD Level II UnitB.pdf#page=38|DMD Level II UnitB, p.38]]
[^39]: Original PDF page 39: [[DMD Level II UnitB.pdf#page=39|DMD Level II UnitB, p.39]]
[^40]: Original PDF page 40: [[DMD Level II UnitB.pdf#page=40|DMD Level II UnitB, p.40]]
[^41]: Original PDF page 41: [[DMD Level II UnitB.pdf#page=41|DMD Level II UnitB, p.41]]
[^42]: Original PDF page 42: [[DMD Level II UnitB.pdf#page=42|DMD Level II UnitB, p.42]]
[^43]: Original PDF page 43: [[DMD Level II UnitB.pdf#page=43|DMD Level II UnitB, p.43]]