Quartz 4

Anterior Tooth Selection REVIEW

5 min read

The focus on anterior tooth selection and aesthetics is critical in complete denture fabrication, as it is considered the most important factor in this region. The successful result relies on ensuring the size, form, texture, colour, and arrangement of the teeth harmonise with the patient’s facial features.

Here is a detailed breakdown of the aesthetic factors considered for anterior teeth, specifically regarding form, proportion (size), contour, and overall arrangement:

I. Form (Shape)

Anterior tooth form refers to the general shape of the tooth crown, traditionally derived from classification systems based on facial outlines:

  1. J. Leon Williams Classification: The foundational forms used for selection are:
    • Square.
    • Tapering.
    • Ovoid.
  2. Selection by Facial Shape: Tooth form is matched to the patient’s face outline. Face outlines are grouped into four main groups with three primary modifications reflecting an ovoid influence. Examples of resulting classifications include:
    • Square.
    • Square Tapering.
    • Tapering Ovoid.
  3. Selection by Anatomical Cast Shape: The shape of the edentulous alveolar ridge can also guide selection:
    • An Oval alveolar ridge suggests an oval anterior tooth shape.
    • A Square alveolar ridge suggests a square anterior tooth shape.
    • A Pointed alveolar ridge suggests a triangular tooth shape.
  4. Mould Numbering System: The First number in the IPN mould numbering system designates the classification (form), such as 1 for Square, 4 for Tapering, or 6 for Ovoid.

II. Proportion (Size: Length and Width)

The selection of appropriate tooth size is vital for aesthetics and is typically assessed during the contour rims appointment (Visit 3).

  1. Length: The maxillary central incisors are conventionally sized at approximately 9 – 12 mm in length. Mould charts list the specific Length of Central Without Collar.
  2. Width Estimation Methods: Several methods using anatomic averages help determine the required total width of the six anterior teeth:
    • The width of the philtrum is suggested to equal the width of the two central incisors.
    • The ala width (of the nose) is said to correspond to the width from mid-canine to mid-canine.
    • A 16:1 ratio exists between the length and width of the face and the width of the upper central incisors.
    • The width can be measured on the occlusal rim from canine to canine.
    • Photographic methods can be used, correlating the width of the six anterior teeth in a photo relative to the interpupillary width in the photo, and applying this ratio to the actual interpupillary width.
  3. Modifying Factors: Size selection can be influenced by available inter-ridge space, reduced oral commissure, and the lengths of the upper and lower lips.
  4. Mould Numbering System:
    • The Letter (e.g., C, E, G, H) corresponds to the Width of Six Anterior Teeth on Curve (e.g., E is 48.00 to 49.00 mm).
    • The Second number relates to Proportion (Long, Medium, Short).

III. Contour and Texture

Contour relates to the facial curvature of the tooth, while Texture involves surface features:

  1. Facial Contour of the Tooth: The Second number in the IPN mould system also classifies the facial contour of the tooth as either Straight or Curved.
  2. Denture Base Contour/Lip Support: The peripheral thickness of the denture base must be adjusted based on the patient’s facial contours and the degree of lip support required for proper aesthetics.
  3. Texture: Anterior tooth selection involves choosing a texture that aims to mimic the surface features of natural teeth.

IV. Shade (Colour)

Shade determination should harmonise with the patient and involves specific considerations for edentulous patients:

  1. General Correlation: For edentulous patients, the chosen shade should reference the colour of the hair, skin, and eyes.
    • Patients with black or grey hair often have more blue or grey shades in their teeth.
    • Blondes and redheads often have more yellow and brown shades.
    • Natural teeth generally darken with age.
  2. Colour Gradation: The colour should show a natural gradation across the tooth surface: darker near the gingival margin and becoming more translucent toward the incisal tip.
  3. Tooth-to-Tooth Variation: There should be subtle variation between pairs of anterior teeth (centrals < laterals < canines).
  4. Patient Input: When discussing shade selection, the patient should not be allowed to select directly from the shade guide.

V. Arrangement and Positioning

The final position of the anterior teeth is crucial for facial aesthetics and is assessed during the wax try-in (Visit 4).

  1. Aesthetic Importance: The contour of the maxillary arch and the placement of the individual anterior teeth contribute the most crucial contribution to the appearance of the face.
  2. Midlines: The dental midline should not deviate from the facial midline by more than 2 – 4 mm.
  3. Incisal Display:
    • At rest, the desirable exposure of maxillary incisors is 2–4 mm.
    • When smiling, the goal is to expose the entire crown of the maxillary incisors.
  4. Lip Relationship:
    • The lower lip should typically cover the incisal third of the maxillary incisors.
    • The ability to comfortably hold lips together at rest indicates competence.
  5. Occlusal Plane: The occlusal plane should normally be parallel to the interpupillary line and the ala-tragal lines (Camper’s plane).
  6. Facial Harmony Systems: Methods for guiding arrangement based on facial characteristics include:
    • Selection by constitution (Kretschmer).
    • Gysi (Physiognomy).
    • Williams (based on form).
  7. Gerber’s Guideline: This method uses the contour of the nasal baseline to serve as a guideline for tooth positioning.
  8. Phonetic Validation: Correct placement of the anterior teeth and occlusal plane is validated by the patient’s ability to enunciate certain sounds:
    • The f, v, and ph sounds are tested, as they require the lower lip to contact the incisal edges of the upper anterior teeth, determining the proper height and placement.
    • The s sound helps establish the correct occlusal vertical dimension (OVD) and can indicate if mandibular anterior teeth are positioned too far lingually (lisp).

Graph View

Backlinks