Figure 1.
Figure 2.
3D distances and angles_
| 3D distances | Definition | 3D angles | Definition |
|---|---|---|---|
| Eye distance | Distance between exR-exL | Mid-face angle | Angle between exR-pg-exL |
| Nose width | Distance between alR-alL | Face convexity | Angle between s-sn-pg |
| Basal width | Distance between acR-acL | Nose prominence | Angle between n-pr-sn |
| Total face height | Distance between n-pg | Philtrum depth | Angle between prn-sn-ls |
| Lower face height | Distance between ls-pg | ||
| Mid- face height | Distance between ls- mid |
Prevalence of facial soft-tissue, maxillary arch and incisor shapes_
| Unilateral palatal canine [n, (%)] | Control [n, (%)] | P-value | |
|---|---|---|---|
| Facial shape | |||
| Tapered | 22 (41) | 12 (22) | |
| Square | 22 (41) | 29 (54) | |
| Ovoid | 10 (19) | 13 (24) | 0.1383 |
| Maxillary arch shape | |||
| Tapered | 19 (35) | 11 (20) | |
| Square | 7 (13) | 5 (9) | |
| Ovoid | 28 (52) | 38 (70) | 0.1492 |
| UL1 | |||
| Square/tapered | 4 (7) | 4 (7) | |
| Square | 50 (93) | 50 (93) | |
| Square/round | - | - | |
| Ovoid | - | - | 1.0000 |
| UR1 | |||
| Square/tapered | 3 (6) | 3 (6) | |
| Square | 51 (94) | 50 (93) | |
| Square/round | - | 1 (2) | |
| Ovoid | - | - | 1.0000 |
| UL2 | |||
| Square/tapered | 14 (26) | 11 (20) | |
| Square | 6 (11) | 8 (15) | |
| Square/round | 25 (46) | 27 (50) | |
| Ovoid | 9 (17) | 8 (15) | 0.8553 |
| UR2 | |||
| Square/tapered | 8 (15) | 10 (19) | |
| Square | 7 (13) | 7 (13) | |
| Square/round | 32 (59) | 33 (61) | |
| Ovoid | 7 (13) | 4 (7) | 0.8189 |
Facial soft-tissue, maxillary arch and incisor dimensions for the unilateral palatal canine and control groups_
| unilaterally palatal canine group | Control group | Mean difference, 95% CI | P-value | |
|---|---|---|---|---|
| Facial morphology | ||||
| Eyes Distance | ||||
| Mean, SD (mm) | 87.13 (3.23) | 87.29 (4.25) | -0.17 (-1.61, 1.27) | 0.6645 |
| Nose Width | ||||
| Mean, SD (mm) | 31.61 (2.18) | 31.89 (2.51) | -0.28 (-1.18, 0.62) | 0.5314 |
| Basal Width | ||||
| Mean, SD (mm) | 18.91 (1.47) | 20.57 (2.57) | -1.66 (-2.46, -0.87) | < 0.0001* |
| Total Face Height | ||||
| Mean, SD (mm) | 103.12 (6.42) | 103.21 (6.35) | -0.09 (-2.53, 2.35) | 0.7701 |
| Lower Face Height | ||||
| Mean, SD (mm) | 39.55 (3.98) | 40.42 (4.61) | -0.86 (-2.51, 0.78) | 0.1724 |
| Midface Height | ||||
| Mean, SD (mm) | 56.66 (3.53) | 55.69 (3.92) | 0.97 (-0.46, 2.39) | 0.1776 |
| Midface Angle | ||||
| Mean, SD (mm) | 49.04 (2.63) | 48.91 (2.59) | 0.13 (-0.87, 1.12) | 0.6987 |
| Face Convexity | ||||
| Mean, SD (mm) | 163.01 (4.86) | 162.70 (5.35) | 0.31 (-1.64, 2.26) | 0.7509 |
| Nose Prominence | ||||
| Mean, SD (mm) | 101.91 (5.65) | 103.08 (5.63) | -1.16 (-3.31, 0.99) | 0.3758 |
| Philtrum Depth | ||||
| Mean, SD (mm) | 131.96 (9.15) | 131.04 (8.30) | 0.92 (-2.41, 4.25) | 0.5240 |
| Face Ratio | ||||
| Mean, SD | 1.45 (0.19) | 1.46 (0.08) | -0.01 (-0.06, 0.05) | 0.5409 |
| Maxillary arch morphology | ||||
| Intercanine width | ||||
| Mean, SD (mm) | 30.46 (3.32) | 31.89 (3.36) | -1.44 (-2.71, -0.17) | 0.0186 |
| Intermolar width | ||||
| Mean, SD (mm) | 48.27 (3.41) | 49.04 (3.83) | -0.77 (-2.15, 0.61) | 0.2876 |
| Palatal Depth | ||||
| Mean, SD (mm) | 14.19 (2.25) | 13.79 (2.33) | 0.40 (-0.48, 1.27) | 0.4705 |
| Palatal Area | ||||
| Mean, SD (mm2) | 16.43 (2.53) | 16.56 (2.58) | -0.13 (-1.11, 0.84) | 0.4566 |
| Incisor morphology | ||||
| Anterior Bolton ratio | ||||
| Mean, SD | 79.46 (6.07) | 76.59 (4.60) | 2.87 (0.82, 4.93) | 0.0070** |
| UL1 ratio | ||||
| Mean, SD | 1.93 (0.26) | 1.93 (0.26) | 0.00 (-0.10, 0.10) | 0.9459 |
| UR1 ratio | ||||
| Mean, SD | 1.94 (0.23) | 1.96 (0.27) | -0.02 (-0.11, 0.08) | 0.7879 |
| UL2 ratio | ||||
| Mean, SD | 2.54 (1.06) | 2.59 (0.98) | -0.06 (-0.45, 0.33) | 0.7761 |
| UR2 ratio | ||||
| Mean, SD | 2.70 (0.88) | 2.57 (0.88) | 0.13 (-0.21, 0.47) | 0.3494 |
Correlations and P values_
| Variable 1 | Variable 2 | Correlation co-efficient | P value |
|---|---|---|---|
| Eyes distance | Intercanine width | 0.02 | 0.8196 |
| Nose width | Intercanine width | 0.13 | 0.3531 |
| Basal width | Intercanine width | 0.04 | 0.7812 |
| Total face height | Intercanine width | -0.09 | 0.3534 |
| Lower face height | Intercanine width | -0.02 | 0.8557 |
| Mid-face height | Intercanine width | -0.06 | 0.5110 |
| Mid-face angle | Intercanine width | 0.05 | 0.5726 |
| Face convexity | Intercanine width | -0.10 | 0.3166 |
| Nose prominence | Intercanine width | 0.08 | 0.4022 |
| Philtrum depth | Intercanine width | -0.00 | 0.9707 |
| Eyes distance | Intermolar width | 0.08 | 0.3852 |
| Nose width | Intermolar width | 0.11 | 0.2427 |
| Basal width | Intermolar width | 0.15 | 0.1275 |
| Total face height | Intermolar width | 0.04 | 0.7185 |
| Lower face height | Intermolar width | 0.14 | 0.1627 |
| Mid-face height | Intermolar width | -0.03 | 0.7855 |
| Mid-face angle | Intermolar width | -0.01 | 0.8873 |
| Face convexity | Intermolar width | -0.05 | 0.5992 |
| Nose prominence | Intermolar width | 0.13 | 0.1781 |
| Philtrum depth | Intermolar width | 0.02 | 0.8416 |
| Basal width | Anterior Bolton ratio | -0.12 | 0.2006 |
Facial Landmarks_
| Landmark name | Definition |
|---|---|
| Midpoint between the eyes (mid) | The halfway distance between exocanthion left and right |
| Soft tissue nasion (n) | Point in the midline of both the nasal root and nasofrontal suture |
| Exocanthion right (exR) | Outer most point on commissure of right eye fissure |
| Exocanthion left (exL) | Outer most point on commissure of left eye fissure |
| Pronasale (prn) | Most protruded point of apex nasi |
| Subnasale (sn) | Midpoint of angle where lower nasal septum and lips meet |
| Alare right (alR) | Most lateral point of the right alar contour |
| Alare left (alL) | Most lateral point of the left alar contour |
| Alar curvature Right (acR) | Most lateral point in the curved base line of right alar base |
| Alar curvature Left (acL) | Most lateral point in the curved base line of left alar base |
| Labiale superioris (ls) | Midpoint on upper vermilion border |
| Pogonion (pg) | Most anterior midpoint on chin |
Inclusion/exclusion criteria_
| Inclusion criteria | Exclusion criteria |
|---|---|
| Male > 11 years and female > 10 years Caucasian subjects | Non-Caucasian subjects or those with cleft lip and palate or craniofacial syndromes |
| Unilateral palatal canine confirmed clinically and radiographically | Buccal, line of arch or bilateral buccal or palatally impacted maxillary canines |
| Maxillary first permanent molars fully erupted with unrestored mesial proximal surfaces | One or both maxillary first permanent molars extracted or with a restored mesial surface |
| Unrestored proximal surfaces of the six maxillary anterior teeth | Restored or carious proximal surface(s) of any of the six maxillary anterior tooth |
| Fractured or damaged study models |
Sample characteristics_
| Unilateral palatal canine group | Control group | |
|---|---|---|
| Age (mean, SD) | 14.5 (1.7) | 14.3 (2.2) |
| Gender (n) | 54 | 54 |
| Malocclusion (n) | ||
| Class I | 24 | 24 |
| Class II/1 | 8 | 8 |
| Class II/2 | 17 | 17 |
| Class III | 5 | 5 |