Introduction
Materials and method
Sample size calculation
Subjects
Asymmetry group
Control group
Group | Sex | Age (years) | Surgery | Me deviation (mm) | ||||
---|---|---|---|---|---|---|---|---|
Male (n) | Female (n) | Total (n) | Mean ± SD | Le Fort I + BVSOa | Le Fort I + BSSOb | Le Fort I + VSOc + SSOd | Mean ± SD | |
Asymmetry group | 7 | 14 | 21 | 23.0 ± 3.4 | 13 | 6 | 2 | 7.31 ± 4.10 |
Control group | 7 | 14 | 21 | 23.0 ± 3.3 | – | – | – | 1.22 ± 0.80 |
CBCT acquisition
Analysis of asymmetry
3D model generation, registration, and 3D analysis
S. no | Landmarks | Abbreviation | Definition | Reference Author, year | |
---|---|---|---|---|---|
1 | Midline landmarks | Anterior nasal spine | ANS | Tip of the anterior nasal spine of the palatal bone in the hard palate | Jung et al. 2009[20] |
2 | Pt A | Pt A | The point of maximum concavity on the contour of premaxilla below ANS | Damstra et al. 2012[19] | |
3 | Upper incisor midpoint | UIM | Contact point between the upper central incisors | Jung et al. 2009[20] | |
4 | Lower incisor midpoint | LIM | Contact point between the lower central incisors | Jung et al. 2009[20] | |
5 | Pt B | Pt B | The point of maximum concavity on the midline on the alveolar process of mandible | Leung et al. 2018[22] | |
6 | Pogonion | Pog | The most anterior point in the symphysis | Jung et al. 2009[20] | |
7 | Menton | Me | The most inferior point in the symphysis | Jung et al. 2009[20] | |
8 | Bilateral landmarks | Infra orbital foramen | IOF | The external opening of the infra orbital canal, on the anterior surface of the body of maxilla in the right and left sides | |
9 | Zygion | Zyg | Most anterior, lateral point on the zygomatic arch in frontal view in the right and left sides | Ercan et al. 2013[21] | |
10 | Canine fossa | CF | A depression on the anterior surface of the maxilla below the infraorbital foramen and on the lateral side of the canine eminence in the right and left sides | ||
11 | Pyriform aperture | PA | The most concave point on pyriform aperture | ||
12 | Lowest pyriform Aperture | LPA | The lower most point on the concavity of the pyriform aperture | ||
13 | Maxillary tuberosity | MT | Point of maximum convexity on the maxillary alveolar ridge in the right and left sides | ||
14 | Convex point on zygoma | Cx Z | The most convex part of the zygomatic bone (malar) in the lateral view | ||
15 | upper canine | UC | The most prominent point on the buccal surface of the upper canine | Leung et al. 2018[22] | |
16 | Lower canine | LC | The most prominent point on the buccal surface of the lower canine | Leung et al. 2018[22] | |
17 | Upper 1st molar | UM1 | Mesio-buccal cusp of upper 1st molar in the right and left sides | Leung et al. 2018[22] | |
18 | Lower 1st molar | LM1 | Mesio-buccal cusp of lower 1st molar in the right and left sides | Leung et al. 2018[22] | |
19 | Mental foramen | MF | Anterior opening of the mandibular canal on the body of the mandible lateral to and above the mental tubercle in the right and left sides | Suzuki-Okamura et al. 2015[23] | |
20 | Lateral chin points | CP | The most anterior point of chin on the outline of mandibular symphysis at lower canine region in the right and left sides | Leung et al. 2018[22] | |
21 | Gonion lateralis | GoL | Most lateral point between the mandibular corpus and the ramus junction in the right and left sides | Nur et al. 2016 [6] | |
22 | Gonion inferius | GoI | Most inferior point between the mandibular corpus and the ramus junction in the right and left sides | Nur et al. 2016[6] | |
23 | Gonion posterius | GoP | Most posterior point between the mandibular corpus and the ramus junction in the right and left sides | Nur et al. 2016[6] | |
24 | Antegonial notch | AGo | Deepest point of the concavity between the mandibular corpus and the ramus junction in the right and left sides | Nur et al. 2016[6] | |
25 | Condylar | Con | Most superior midpoint of the condylar head in the right and left sides | Nur et al. 2016[6] | |
26 | coronoid | Crn | The most superior point of right coronoid process in the right and left sides | Leung et al. 2018[22] | |
27 | Sigmoid notch | Sig | The depth of concavity at right sigmoid notch in the right and left sides | Leung et al. 2018[22] | |
28 | Orbitale | Or | The most inferior point of the lower margin of the bony orbit in the right and left sides | Damstra et al. 2012[19] | |
29 | Porion | Por | The most superior point of the external auditory meatus in the right and left sides | Leung et al. 2018[22] | |
30 | Nasion | Na | Midpoint of the frontonasal suture | Nur et al. 2016[6] | |
31 | sella | S | Center of the hypophyseal fossa | Nur et al. 2016 [6] | |
Reference Planes | |||||
1 | Horizontal plane | HP | A plane passing through the bilateral orbitales and right porion | Nur et al. 2016[6] | |
2 | Mid-sagittal plane | MSP | A plane perpendicular to HP and passing through the nasion and sella | Nur et al. 2016[6] | |
3 | Coronal plane | CP | A plane perpendicular to the HP and MSP and passing through the right porion | Nur et al. 2016[6] |
Asymmetry index (AI)-based analysis
Zone asymmetry | Landmarks* |
Total facial skeleton | IOF, Zyg, CF, PA, LPA, MT, CxZ, MF, CP, GoP, GoI, GoL, Ago, Crn, Sig, Con, ANS, Pt A, Pt B, Pog, Me |
Total maxilla | IOF, Zyg, CF, PA, LPA, MT, CxZ, ANS, Pt A |
Total mandible | MF, CP, GoP, GoI, GoL, Ago, Crn, Sig, Con, Pt B, Pog, Me |
Part asymmetry | |
Maxilla midline | ANS, Pt A |
Maxilla bilateral | IOF, Zyg, CF, PA, LPA, MT, CxZ |
Mandibular midline | Pt B, Pog, Me |
Mandibular bilateral | MF, CP, GoP, GoI, GoL, Ago, Crn, Sig, Con |
Area asymmetry | |
Chin | Pog, Me, CP |
Ramus | GoP, GoI, GoL, Ago, Crn, Sig, Con |
Clinically derived midline based analysis (CM)
Procrustes analysis (PA)
Modified Procrustes analysis (MPA)
Study error
Statistical analysis
Results
Asymmetry index (AI)-based analysis
Asymmetry group | Control group | ||||||||
---|---|---|---|---|---|---|---|---|---|
T0 | T1 | C | T0-C | T0-T1 | T1-C | ||||
Mean | SD | Mean | SD | Mean | SD | P | P | P | |
Zone AI | |||||||||
Total facial skeleton | 5.17 | 3.59 | 3.31 | 2.04 | 1.61 | 1.21 | < 0.001* | 0.046* | 0.002* |
Total maxilla | 2.37 | 0.87 | 1.95 | 1.01 | 0.78 | 0.36 | < 0.001* | 0.364 | 0.005* |
Total mandible | 7.27 | 3.42 | 4.33 | 2.03 | 2.24 | 1.25 | < 0.001* | 0.018* | 0.006* |
Part AI | |||||||||
Maxilla midline | 1.53 | 0.78 | 1.11 | 0.12 | 0.91 | 0.06 | 0.013* | 0.053 | 0.173 |
Maxilla bilateral | 2.61 | 0.84 | 2.19 | 1.03 | 0.74 | 0.40 | < 0.001* | 0.425 | 0.004* |
Mandibular midline | 7.00 | 0.49 | 2.92 | 0.36 | 1.27 | 0.05 | < 0.001* | < 0.001* | < 0.001* |
Mandibular bilateral | 7.36 | 3.99 | 4.80 | 2.16 | 2.56 | 1.30 | 0.003* | 0.111 | 0.017* |
Area AI | |||||||||
Chin | 9.14 | 3.21 | 4.26 | 2.02 | 1.98 | 1.23 | 0.023* | 0.090 | 0.171 |
Ramus | 5.75 | 2.78 | 4.11 | 1.88 | 2.32 | 1.39 | 0.013* | 0.218 | 0.066 |
Asymmetry score based on clinically derived midline (CM)
Asymmetry group | Control group | ||||||||
---|---|---|---|---|---|---|---|---|---|
T0 | T1 | C | T0-C | T0-T1 | T1-C | ||||
Mean | SD | Mean | SD | Mean | SD | P | P | P | |
Zone AS | |||||||||
Total facial skeleton | 3.64 | 1.49 | 2.92 | 0.86 | 2.01 | 0.50 | < 0.001* | 0.020* | < 0.001* |
Total maxilla | 1.86 | 0.67 | 1.91 | 0.43 | 1.59 | 0.49 | 0.150 | 0.630 | 0.030* |
Total mandible | 4.93 | 2.40 | 3.66 | 1.37 | 2.40 | 0.79 | < 0.001* | 0.010* | < 0.001* |
Part AS | |||||||||
Maxilla midline | 1.43 | 1.36 | 1.18 | 0.79 | 1.09 | 0.86 | 0.340 | 0.290 | 0.740 |
Maxilla bilateral | 1.92 | 0.64 | 2.02 | 0.46 | 1.69 | 0.51 | 0.210 | 0.370 | 0.030* |
Mandibular midline | 7.23 | 4.75 | 2.78 | 2.34 | 1.32 | 0.85 | < 0.001* | < 0.001* | 0.010* |
Mandibular bilateral | 4.62 | 2.18 | 3.83 | 1.30 | 2.57 | 0.85 | < 0.001* | 0.070 | < 0.001* |
Area AS | |||||||||
Chin | 6.99 | 4.44 | 3.14 | 2.03 | 1.89 | 1.08 | < 0.001* | < 0.001* | 0.020* |
Ramus | 4.01 | 1.64 | 3.81 | 1.21 | 2.63 | 0.90 | < 0.001* | 0.550 | < 0.001* |
Asymmetry score based on Procrustes analysis (PA)
Asymmetry group | Control group | ||||||||
---|---|---|---|---|---|---|---|---|---|
T0 | T1 | C | T0-C | T0-T1 | T1-C | ||||
Mean | SD | Mean | SD | Mean | SD | P | P | P | |
Zone AS | |||||||||
Total facial skeleton | 2.20 | 0.90 | 1.90 | 0.32 | 1.32 | 0.28 | < 0.001* | 0.12 | < 0.001* |
Total maxilla | 1.08 | 0.34 | 1.30 | 0.30 | 1.09 | 0.26 | 0.89 | 0.01* | 0.02* |
Total mandible | 1.90 | 0.78 | 1.98 | 0.40 | 1.27 | 0.28 | < 0.001* | 0.64 | < 0.001* |
Part AS | |||||||||
Maxilla midline | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.03* | 0.50 | 0.10 |
Maxilla bilateral | 1.15 | 0.34 | 1.38 | 0.33 | 1.17 | 0.29 | 0.86 | 0.01* | 0.04* |
Mandibular midline | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.49 | 0.40 | 0.16 |
Mandibular bilateral | 2.02 | 0.87 | 2.12 | 0.45 | 1.32 | 0.27 | < 0.001* | 0.64 | < 0.001* |
Area AS | |||||||||
Chin | 0.73 | 0.46 | 0.70 | 0.46 | 0.55 | 0.42 | 0.21 | 0.82 | 0.29 |
Ramus | 1.96 | 0.86 | 2.23 | 0.48 | 1.31 | 0.30 | < 0.001* | 0.21 | < 0.001* |
Asymmetry score based on modified Procrustes analysis (MPA)
Asymmetry group | Control group | ||||||||
---|---|---|---|---|---|---|---|---|---|
T0 | T1 | C | T0-C | T0-T1 | T1-C | ||||
Mean | SD | Mean | SD | Mean | SD | P | P | P | |
Zone AS | |||||||||
Total facial skeleton | 3.28 | 1.54 | 2.73 | 0.79 | 1.83 | 0.53 | < 0.001* | 0.080 | < 0.001* |
Total maxilla | 1.76 | 0.62 | 1.85 | 0.62 | 1.53 | 0.47 | 0.180 | 0.610 | 0.070 |
Total mandible | 4.37 | 2.50 | 3.38 | 1.17 | 2.12 | 0.76 | < 0.001* | 0.050 | < 0.001* |
Part AS | |||||||||
Maxilla midline | 1.37 | 1.07 | 1.11 | 1.11 | 1.24 | 0.81 | 0.640 | 0.440 | 0.690 |
Maxilla bilateral | 1.81 | 0.59 | 1.96 | 0.63 | 1.59 | 0.47 | 0.200 | 0.340 | 0.040* |
Mandibular midline | 6.44 | 4.91 | 2.37 | 2.40 | 1.55 | 1.01 | < 0.001* | < 0.001* | 0.160 |
Mandibular bilateral | 4.09 | 2.24 | 3.56 | 1.09 | 2.20 | 0.80 | < 0.001* | 0.250 | < 0.001* |
Area AS | |||||||||
Chin | 6.19 | 4.63 | 2.62 | 1.98 | 2.05 | 1.31 | < 0.001* | < 0.001* | 0.280 |
Ramus | 3.53 | 1.68 | 3.61 | 1.02 | 2.16 | 0.76 | < 0.001* | 0.810 | < 0.001* |