Quartz 4

Facial Profile Analysis

7 min read

Facial Profile Analysis

Facial Form Analysis (Frontal) — Full Breakdown

1. Symmetry

  • What to look for:
    • Draw a vertical midline through glabella → subnasale → pogonion
    • Check whether the chin deviates from this line
    • Check whether the dental midlines (upper and lower) coincide with the facial midline (philtrum)
  • Decide:
    • Within normal limits — no noticeable deviation (chin < 3-4 mm off midline, dental midline < 3 mm off)
    • Asymmetric — note the location: upper face, lower face (mandibular), or both
  • Key thresholds:
    • Chin deviation > 4 mm is consistently noticed by clinicians and patients
    • Dental midline off facial midline > 3 mm becomes a treatment priority
    • Over 80% of noticeable facial asymmetry involves the mandible

2. Vertical Facial Proportions (Thirds)

  • What to look for:
    • Divide the face into three horizontal thirds: hairline (Trichion) → Glabella → Subnasale → Menton
    • Assess whether the lower third is proportionate to the middle third
    • Further subdivide the lower third: Subnasale to Stomion = 1/3, Stomion to Menton = 2/3
  • Decide:
    • Normal proportions — thirds approximately equal; lower third 1/3 : 2/3 ratio maintained
    • Long face — lower third disproportionately long; often associated with excessive gingival display, steep mandibular plane, open bite tendency
    • Short face — lower third disproportionately short; associated with deep overbite tendency

3. Transverse Facial Proportions (Fifths)

  • What to look for:
    • Divide the face into 5 equal vertical segments (helix → outer canthus → inner canthus → inner canthus → outer canthus → helix)
    • Check whether the intercanthal width matches the alar base width
    • Check whether mouth width approximates inter-pupillary distance
  • Decide:
    • Proportionate — fifths approximately equal
    • Disproportionate — note which segment is wider/narrower; asymmetry between corresponding sides suggests skeletal asymmetry

4. Facial Cant

  • What to look for:
    • Compare the interpupillary line, alar base line, and commissural line — all should be parallel and horizontal
    • If using a tongue depressor across premolars/molars, the occlusal plane should also be parallel to the interpupillary line
  • Decide:
    • No cant — horizontal lines are parallel
    • Cant present — note which side is higher/lower; indicates differential vertical growth

5. Incisor Tooth Display

  • What to look for:
    • At rest: mm of maxillary incisor visible (normally 2-4 mm)
    • On social smile: percentage of crown displayed (ideal = 100% + small gingival show)
    • Amount of gingival display (2-3 mm acceptable; more = “gummy smile”)
  • Decide:
    • OK — adequate display at rest and smile
    • Too little — incisors barely visible; aged appearance
    • Too much — excessive gingiva on smile → vertical maxillary excess

6. Buccal Corridor Width

  • What to look for:
    • Dark space between posterior teeth and cheeks on smile
  • Decide:
    • OK — small buccal corridor present
    • Too much — wide dark corridors → narrow maxillary arch, may need expansion
    • Too little — teeth fill entire smile width → overdone transverse dimension

7. Smile Arc

  • What to look for:
    • Curvature of maxillary incisor edges relative to lower lip curvature on social smile
  • Decide:
    • OK — curves are consonant (parallel, matching)
    • Flat — maxillary incisor edges form a flat line rather than following the lip → detracts from esthetics
    • Excessive — maxillary incisors curve too far below the lower lip contour

8. Frontal Summary Statement

  • Template: “Facial symmetry: ___. Vertical proportions: ___. Transverse proportions: ___. Incisor display: ___. Buccal corridors: ___. Smile arc: ___.”

Facial Profile Analysis (Lateral) — Full Breakdown

  1. Antero-posterior skeletal jaw relationship (Class I / II / III)

    • What to look for (soft tissue “x‑ray vision”):
      • Overall profile shape: straight/slightly convex (often Class I) vs more convex (Class II tendency) vs concave (Class III tendency).
      • Alignment of key points in profile: bridge of nose → base of upper lip → chin.
      • Soft tissue contours reflect underlying hard tissue: chin position reflects mandibular position; upper lip/nasal base reflects anterior maxilla.
      • Sketching the profile on paper forces you to look carefully — valuable for developing “x-ray vision.”
    • Decide:
      • Class I: no obvious jaw discrepancy (can still have crowding/proclination). Bridge of nose, base of nose, and chin line up in a straight or very slightly convex line.
      • Class II: mandible relatively retrusive vs maxilla (convex profile). Can be due to mandibular deficiency, maxillary excess, or combination.
      • Class III: mandible relatively protrusive and/or maxilla deficient (concave profile). ~1-2% of US population; up to 14% in Asian populations. You don’t need an x-ray to see this.
    • Soft tissue A-B measurement (from ceph norms):
      • Class I normal range: -2 to 6 mm distance between soft tissue points A and B
      • > 6 mm → skeletal Class II
      • > -2 mm (i.e., B ahead of A) → skeletal Class III

  2. Mandibular plane angle relative to Frankfort plane

    • What to look for (clinical cue):
      • Estimate mandibular plane steepness (often demonstrated with a straight edge/mirror handle).
    • Decide:
      • Steep mandibular plane: commonly associated with long face pattern (downward-backward mandibular rotation).
      • Moderate: within typical range.
      • Low/flat mandibular plane: commonly associated with short face pattern.

Determining Low, Moderate, Steep

  • FMA (FH–MP) typical reference values:
  • Average/normal: ~25° (often cited normal range about 22–28°)
  • Low angle (hypodivergent): <~20°
  • High angle (hyperdivergent): >~30°
  • Clinical use: higher FMA → steeper mandibular plane / long-face tendency; lower FMA → flatter plane / short-face tendency.
  • Important: these are ceph-based norms; in photo-only profile analysis you can only estimate “steep/moderate/low,” not measure precisely.

  1. Vertical skeletal jaw relationship (normal / long face / short face)

    • What to look for:
      • Relative height of lower facial third (and whether the face looks vertically long or short).
      • Signs of mandibular rotation (down/back rotation aligns with long-face tendency).
      • Gingival display can increase with long-face pattern (maxilla grown downward more).
    • Decide:
      • Normal — lower third proportionate
      • Long face — disproportionately long lower third; excessive maxillary downward growth causes downward-backward mandibular rotation → steep mandibular plane, often open bite tendency. Increased gingival display on smile.
      • Short face — disproportionately short lower third; often predisposes to deep overbite (skeletal deep bite). Flat mandibular plane angle.

  2. Tooth support for lip (excessive / normal / inadequate)

    • What to look for:
      • Whether incisors appear to be pushing the lips forward (more support) or lips look under-supported/flat.
    • Interpretation:
      • Incisors forward → increased lip support/prominence.
      • Incisors back → decreased support/prominence.

  3. Lip prominence (excessive / normal / inadequate)

    • How to judge (lips relaxed):
      • Upper lip relative to a vertical reference through soft tissue point A.
      • Lower lip relative to a vertical reference through soft tissue point B.
      • Also assess using E-line (Ricketts): tip of nose → soft tissue chin. Lips should be 2-4 mm behind this line (Caucasian norms).
    • Clinical signs of excessive incisor protrusion (triad):
      • Lips prominent — forward of reference lines
      • Lips incompetent at rest — > 3-4 mm separation (best seen in oblique/three-quarter view)
      • Lips strained on closure — mentalis strain, chin dimpling when patient tries to close lips
      • If all three are present → anterior teeth are excessively protrusive
    • Why this matters:
      • Moving incisors facially increases lip support and prominence
      • Moving incisors lingually decreases lip support and prominence
      • This assessment is a primary determinant of whether to expand the arch or extract teeth to resolve crowding

  4. Summary statement (A‑P + vertical + lip support)

    • Template (fill-in):
      • “Profile: skeletal A‑P Class ___, vertical ___ face, mandibular plane steep/moderate/low, lip prominence ___, tooth (incisor) lip support ___.”
      • Optional add-on if relevant: “Findings suggest incisor position is protrusive/retrusive/normal relative to soft tissue.”

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