Quartz 4

L5 AnteriorTooth Arrangement

15 min read

Complete Denture Overview12

Note

This lecture covers the principles of facial aesthetics, the selection of appropriate artificial teeth for edentulous patients, and the aesthetic arrangement of these teeth on a wax rim for a try-in appointment. The content combines both clinical and laboratory procedures.

Treatment Schedule

Note

The procedures discussed in this lecture align with Visit Three of the complete denture treatment schedule, encompassing:

  • ==Clinical Procedures: Shade determination and anterior tooth selection.==
  • ==Laboratory Procedures: Articulation and tooth setting.==
VisitOperatorProcedure
Visit 1Clinician
Laboratory		Patient evaluation & primary impressions
Diagnostic casts & special trays
Visit 2Clinician
Laboratory		Secondary impressions
Bead & box, master casts, base & rims
Visit 3Clinician
Laboratory		Contour rims, OVD, MMR, shade & mould selection
Articulation & tooth setting
Visit 4Clinician
Laboratory		Wax try-in
Finalisation & processing
Visit 5ClinicianAssessment & issue
Instructions for care
Visit 6ClinicianPost operative review, post insertion instructions

Facial Aesthetics3

Successful alteration of dentofacial form requires an understanding of facial aesthetics.

Note

This involves not only technical knowledge but also a deep understanding of the patient’s needs and perceptions.

The patient’s presenting complaint is important, as is an understanding of the patient’s:

  • Perception of his/her dentofacial appearance

  • Address the patient's primary concerns. If a patient is unhappy with the appearance of their existing denture, creating a new one with the same mould, shade, and arrangement will not resolve the issue.

  • Motivation for seeking treatment

  • Realism of his/her expectations from treatment; and

  • ==Patients may have unrealistic expectations. It is important to remember and communicate that dentures are an alternative to being edentulous, not a substitute for natural teeth.==

  • Likely level of co-operation, as well as support of the family and friends

  • ==Managing Expectations: If a patient’s existing dentures have no obvious aesthetic or functional defects that can be remedied, it is wise to seek advice from a mentor or refer to a specialist. Proceeding without a clear path for improvement can lead to patient dissatisfaction and potential regulatory issues (e.g., with AHPRA - Australian Health Practitioner Regulation Agency).==

  • ==Patient Information: Successful treatment requires a cooperative patient who understands the time and effort involved. This is achieved by providing timely and relevant information before, during, and after the treatment process.==

  • ==Social Support: The influence of family and friends cannot be underestimated. Well-meaning but uninformed comments can create patient discontent (e.g., a friend asking

Naini & Gill, 2008

Facial Landmarks4

  1. Trichion (hairline)
  2. Glabella (most prominent point of soft tissue drape of forehead)
  3. Soft tissue nasion (deepest point of concavity between forehead & nose)
  4. Subnasale (where nasal columella meets the upper lip
  • The angle at this junction is an important indicator of lip support.

) 5. Labrale superioris (vermilion border of upper lip) 6. Stomion (midpoint of interlabial fissure) 7. Labrale inferioris (vermilion border of lower lip) 8. Labiomental fold (point of greatest concavity between labrale inferioris & soft tissue menton

  • This indicates the adequacy of lower lip support.

) 9. Soft tissue pogonion (most prominent point on soft tissue of chin) 10. Soft tissue menton (most inferior point on soft tissue of chin)

Typical Facial Proportions56

  • Facial height to width (white):
    • Males = 1.35:1
    • Females = 1.30:1
  • Bizygomatic width (white):
    • = 70% facial height (white)
  • Bitemporal width (red):
    • = 80 – 85% bizygomatic width
  • Bigonial width (blue):
    • = 70 - 75% bizygomatic width

Naini & Gill, 2008

  • Vertical facial thirds:

    • Are approximately equal

  • ==Upper Third: Trichion to Glabella.==

    • ==Middle Third: Glabella to Subnasale.==
    • ==Lower Third: Subnasale to Soft Tissue Menton.==

  • Lower facial third:

    • May be greater than middle third especially in males

  • Lower facial third can be further subdivided with:

    • Upper lip forming one third
    • Lower lip and chin forming remaining two thirds

Naini & Gill, 2008

  • Transverse face:

    • Can be divided into equal fifths
    • Each fifth equals one eye width

  • Nasal alar base:

    • Should equal the intercanthal distance

  • Mouth width:

    • Equals the distance between the medial iris margins

  • Dental Midline:

    • Should be within 2-4 mm of facial midline

  • ==The angulation of the maxillary incisors is critical. Incorrect angulation can make even minor midline deviations more obvious to a lay observer.==

Naini & Gill, 2008

Dental Midlines78

Naini & Gill, 2008

Complete Dentures9

Conventional Aesthetic Norms

  • The denture provides adequate lip support

  • Normally the occlusal plane is parallel to the interpupillary and ala-tragal lines

  • Dental midline should not vary from facial midline by more than 2 – 4 mm

  • The size, form, texture, colour and arrangement of the teeth harmonise with the patient’s facial features:

    • Maxillary central incisors are approximately 9 – 12 mm in length
    • Vermillion show of lower lip slightly more than upper lip
    • Lower lip should cover incisal third of maxillary incisors
    • Competent lips can be comfortably held together at rest
    • There should be 2-4 mm exposure of maxillary incisors at rest

  • On smiling, the entire crown of the maxillary incisors should be visible.

Naini & Gill, 2008

Incisal Display10

rest posed spontaneous

Factors affecting incisor exposure:

  • Upper lip length
  • The “smile curtain” – defined as the muscular ability to raise the upper lip
  • The vertical position of the anterior maxilla and incisor teeth
  • The anteroposterior position of the anterior maxilla and incisor teeth
  • The inclination of the maxillary incisor teeth
  • Maxillary incisor crown length
  • The vertical level of the gingival margins on the labial surface of the maxillary incisor crowns

The vertical exposure of the incisors at rest should be 2-4 mm and on smiling the entire crown of the maxillary incisors should be exposed

Naini & Gill, 2008

Anterior Tooth Selection11

Anteriorly Aesthetics is the most important factor

Posteriorly Function is the most important factor

Determining Factors12

  • Size

    • Length
    • Width

  • Form (as per J. Leon Williams)

    • Square
    • Tapering
    • Ovoid

  • Texture

    • Mimic surface features of natural teeth

  • Shade

    • For edentulous patients refer to colour of hair, skin & eyes
    • Gradation from gingival margin (darker) to incisal tip (more translucent)
    • Variation between pairs of anterior teeth, centrals < laterals < canines

  • Material

    • Porcelain

  • Most aesthetic and wear-resistant but can crack on impact and wear opposing teeth.

    • Composite resin
    • Acrylic Resin

  • Currently the most popular due to advances in polymer chemistry.

Size13

Pre-extraction records

  • remaining teeth
  • photographs with teeth in place
  • radiographs of teeth
  • measure existing denture

Anatomic averages

  • width of philtrum = 2 centrals

  • 16:1 ratio between length & width of face and upper centrals

  • canine to canine width on occlusal rim

  • A flexible ruler is useful for measuring this curve.

  • ala width corresponds to mid canine to mid canine width

Modifying factors

  • inter-ridge space
  • reduced oral commissure
  • upper and lower lip lengths

calculate with this formula

Width of upper six anterior teeth (photo)=width of upper six anterior teeth
Interpupillary width (photo)Interpupillary width (actual)
  • Transfer markings from maxillary rim
  • Measure inter-canine width on maxillary rim
  • Measure height of smile line

Form1415

Selection by facial shape

Note

Dr. Leon Williams’ Classification: Proposed three primary tooth forms that correspond to facial shapes: Square, Tapering, and Ovoid. Dentsply Classification: Expanded on Williams’ system by adding combination shapes and subgroups (Square Ovoid, Square Tapering Ovoid, Tapering Ovoid).

Face outline can be classified into four main groups with three primary modifications of the basic face forms which reflect a softening or ovoid influence

  • square
  • square ovoid
  • square tapering
  • square tapering ovoid
  • tapering
  • tapering ovoid
  • ovoid

Selection using anatomical cast16

Oval alveolar ridge

oval anterior tooth shape

Pointed alveolar ridge

triangular tooth shape

Square alveolar ridge

square anterior tooth shape

Selection of IPN Anterior Teeth17

Mould Guide

Note

This is a physical kit containing monochrome replicas of every available tooth mould. Moulds are grouped by face type. It allows the operator to test a proposed mould directly on the working cast to confirm size and position. [!warning] Note

Mould guide teeth are for selection only and are not suitable for clinical use.

Mould Classification1819

Note

Manufacturers provide a printed mould chart with life-size images and detailed data for each mould. The data provided includes the mould number, length of the central incisor (without collar), width of the central, width of the 6 anteriors on a curve, and the corresponding lower mould for articulation.

First number: Classification

Example

‘2’ indicates a Square Tapering mould.

  1. Square
  2. Square Tapering
  3. Square Ovoid
  4. Tapering
  5. Tapering Ovoid
  6. Ovoid
  7. Square Tapering Ovoid

Second number: Proportion & Contour

Example

‘2’ indicates a tooth of medium proportion and straight facial contour.

Proportion of the ToothFacial Contour
1. LongStraight
2. MediumStraight
3. ShortStraight
4. LongCurved
5. MediumCurved
6. ShortCurved

Letter: Width of Six Anterior Teeth on Curve

Example

‘E’ indicates a width in the 48-49 mm range.

  • B. less than 44.00 mm
  • C. 44.00 to 45.50 mm
  • D. 45.50 to 48.00 mm
  • E. 48.00 to 49.00 mm
  • F. 49.00 to 51.50 mm
  • G. 51.50 to 54.00 mm
  • H. 54.00 to 56.00 mm
  • J. 56.00 mm or greater

Some moulds may vary from this standard. Please consult mould chart dimensions.

Mould Availability (OHCWA)20

Upper Anteriors

OHCWA Stock

This is the specific list of anterior tooth moulds stocked at OHCWA. It is recommended to save or print this list for easy reference. While other moulds can be requested, they may need to be ordered from the USA, which can take months.

CodeTypeDimensions (mm)Notes
12EPortrait - Bioform50.00, 8.50, 45.50, 10.60M N
12GPortrait - Bioform53.00, 9.15, 49.00, 10.60G R V
21CPortrait - Bioform45.50, 17.70, 42.00, 10.00C
22CPortrait44.50, 17.70, 41.00, 9.85C
32BPortrait44.00, 17.50, 40.50, 9.20C
42GPortrait - Bioform52.00, 8.70, 48.00, 10.40O P
43FPortrait - Bioform49.00, 8.80, 45.50, 9.60M N X
54FPortrait - Bioform49.00, 8.65, 45.00, 11.50J N
74HPortrait - Bioform54.00, 9.00, 50.00, 12.25K1

Lower Anteriors

Note

The selection of a lower anterior mould depends on the upper mould and the patient’s jaw relationship.

  • ==Class I: Use the recommended lower mould(s) listed on the upper mould’s data card.==
  • ==Class II: A narrower lower mould may be required.==
  • ==Class III: A wider lower mould may be required.==
CodeTypeDimensions (mm)Notes
CPortrait - Bioform35.00, 4.90, 31.50, 9.00
JPortrait - Bioform40.50, 15.50, 35.50, 10.25
MPortrait - Bioform39.50, 15.05, 35.00, 8.60
NPortrait - Bioform38.00, 15.20, 33.50, 9.10
WPortrait - Bioform42.00, 5.75, 39.00, 10.25

Articulation Key

Note

The data card for each upper mould includes a suggestion for the lower mould(s) best suited for articulation in a Class I relationship. For example, for upper mould 12E, the recommended lower moulds are M or N.

  • 21C: Maxillary Anterior
  • Curve / Straight: 46.50 / 42.00
  • Shades: Portrait PN available in all 24 + 3 shades, Bioform PN check mould/shade availability on page 19.

Shade Determination21

Factors to consider

  • When discussing shade selection with a patient do not let them select directly from the shade guide

  • Instead, select two or three shades that are harmonious with the patient's complexion and ask them to choose from that limited selection. This engages them in the process while guiding them toward a natural result.

  • The shade, or colour, of the teeth should be in harmony with the patient

  • There is a definite correlation between complexion and tooth shade

  • ==Eye Color: Hold the shade tab next to the patient’s eyes. If the tab is significantly brighter than the sclera (the white of the eye), the value is too high.==

  • Natural teeth darken with age

  • Black- or grey-haired patients usually have more blue or grey shades in their teeth

  • Blondes & redheads will often have more yellow and brown shades in their teeth

IPN Shade Guide22

OHCWA Availability

The Portrait IPN shade guide is used. The fourth tab from the left is equivalent to Vita shade A1, which is a very light shade for natural teeth. The three shades to the left of A1 were created for

Anterior Tooth Arrangement2324

Principles

  • Proper placement of teeth should be functionally as well as aesthetically pleasing
  • The contour of the maxillary arch and the arrangement of the individual teeth make the most crucial contribution to the appearance of the face
  • The goal of setting artificial teeth is quite simply to put them where the natural teeth were (Bissau, 1992)
  • Occlusion is not the only important factor when arranging teeth

Tooth Positioning25

Standard Angulations26

Gerber27

The contour of the nasal baseline serves as a guideline for tooth positioning

  • ==Square Nasal Baseline: A flat incisal edge contour.==
  • ==Tapered Nasal Baseline: A pronounced, sharp curvature.==
  • ==Ovoid Nasal Baseline: A more rounded curvature.==

Arrangement by facial shape28

Facial Harmony Gysi

Physiognomy Williams

  • ==Square Face: Teeth arranged with a squarer arch form.==
  • ==Tapering Face: Teeth arranged with a more V-shaped arch form.==
  • ==Ovoid Face: Teeth arranged in a rounded arch form.==

Selection by constitution (Kretschmer)

Note

Kretschmer proposed selecting tooth shapes based on the patient’s body type (constitution):

  • ==Pyknic: Rounded body, large chest, short neck. Suggested tooth shape: Oval.==
  • ==Leptosome: Frail body, long-limbed, narrow-chested. Suggested tooth shape: Triangular.==
  • ==Athletic: Muscular, angular build. Suggested tooth shape: Square.==

Maxillary Teeth29

Setting Process (using mould 42G as an example)

  1. Set Central Incisors First: Scoop out wax on one side of the scribed midline, heat the wax socket, and position the first central incisor (tooth 11). - The mesial edge must align perfectly with the denture midline. - The neck should be depressed and the long axis distally inclined. - There should be ~1 mm of vertical and horizontal overlap with the opposing teeth/rim.
  2. Set the Other Central Incisor: Set the second central incisor (tooth 21) next. Setting both centrals first makes it easier to confirm the midline is correct before proceeding.
  3. Set Remaining Anteriors: Once the centrals are confirmed, set the lateral incisors and canines according to the standard angulations.
  4. Set First Premolars: It is helpful to also set the first premolars at this stage to ensure the anterior arrangement allows for correct placement of the posterior teeth.

42G - tapering

Incisal Guide Angle3031

Defined as: The angle made to the horizontal by a line drawn, in the sagittal plane, between the incisal edges of the upper and lower incisors.

Clinical Goal

For denture stability, this angle should be kept as low as possible, preferably around 10 degrees. A steep angle makes achieving balanced occlusion more difficult. On an adjustable articulator, the incisal guide table should be set to the desired angle.

A – B = Incisal Guide Angle

In complete dentures the mandibular incisors should not touch the maxillary incisors in intercuspal position

The purpose of horizontal and vertical overlap of the incisor teeth is to facilitate aesthetics, phonetics and function of balance in protrusion

Mandibular Teeth32

Note

Although not part of the practical exercise, understanding the arrangement of mandibular teeth is crucial for achieving balanced occlusion.

  • ==Overjet and Overbite: In the intercuspal position, mandibular incisors should not touch the maxillary incisors. There must always be a degree of horizontal overlap (overjet) and vertical overlap (overbite), typically around 1 mm each. This facilitates aesthetics, phonetics, and balanced function in protrusion.==
  • ==Setting Process: 1. As with the maxilla, it is best to set the two central incisors first to easily align the mandibular and maxillary midlines. 2. Position the remaining anterior teeth. 3. Canine Relationship: The central ridge of the upper canine should align with the distal edge of the lower canine.==
  • ==Excursive Movements: The final arrangement should allow for even incisal contact without interferences during lateral excursions.==

Flashback33

Road Mobile Clinic

Note

In the 1960s, Perth Dental Hospital operated three road mobile clinics to serve remote areas. One clinic was built on a Bedford bus chassis, while the other two were semi-trailers. These clinics operated in harsh conditions, such as the route between Morawa and Meekatharra, encountering corrugated roads and red dust. The generator was for use in towns without a 240-volt power supply.

Circa 1960’s. Still around today Fully self-contained dental clinic. Prime mover with 50 KVA generator used to transport two identical trailers. Clinic had three rooms – surgery, waiting room and laboratory – and a plant room

Surgery equipment34

  1. Stand-up dental chair, Operating light, X-ray unit, Belt drive low speed motor and handpiece, Bracket table
  2. Writing desk, Cabinetry, Limited bench space, Handbasin
  3. Autoclave, Sterilising area, Refrigerator, High speed unit

Note

The windows were small and placed very high, as the superintendent at the time believed that looking outside was a distraction from work.

Thank You35

Any questions? Contact me

Dr Ian Lander ian.lander@uwa.edu.au

Footnotes

  1. Original PDF page 1: L5 AnteriorToothArrangement, p.1 ↩

  2. Original PDF page 2: L5 AnteriorToothArrangement, p.2 ↩

  3. Original PDF page 3: L5 AnteriorToothArrangement, p.3 ↩

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  34. Original PDF page 34: L5 AnteriorToothArrangement, p.34 ↩

  35. Original PDF page 35: L5 AnteriorToothArrangement, p.35 ↩

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