Introduction
Subjects and methods
Trial design
Participants, eligibility criteria, and settings
Sample size
Intervention
Blinding
Outcome—facial expressions
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the lower face: the area of the lower face limited by a plane through the landmark subnasale parallel to Frankfort Horizontal containing the same automatically selected 559 points for each participant, and
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the landmarks undergoing the biggest change during facial expression: cheilion left and right for maximum smile, and labrale superius and inferius for lip purse.
Outcome | Definition |
---|---|
Magnitude, mm | Magnitude of facial expression in the most moving area of the lips For maximum smile: \(magnitude= \frac{{ d}_{Cheilion right}+{d}_{Cheilion left}}{2}\) For lip purse: \(magnitude= \frac{{ d}_{Labrale superius}+{d}_{Labrale inferius}}{2}\) |
Shape change, mm | Shape change in the lower face during the facial expression calculated as Procrustes distance after superimposing the 3D image of the start and end frame by translating, scaling and rotating as the square root of the sum of squared differences in the positions of all landmarks of the lower face |
Symmetry, mm | Differences in facial expression between the two most moving areas of the lips For maximum smile: \(symmetry= \left|{d}_{Cheilion right}-{d}_{Cheilion left}\right|\) For lip purse: \(symmetry= \left|{d}_{Labrale superius}-{d}_{Labrale inferius}\right|\) |
Time, s | Time needed to reach the maximum facial expression |
Method error analysis
Statistical analysis
Results
Participant flow and recruitment
Gender | |
Female | n = 15 |
Male | n = 11 |
Age, years | M = 28.4 SD = 8 |
Skeletal class II Wits appraisal, mm | n = 13 M = 5.2 SD = 1.6 |
Skeletal class III Wits appraisal, mm | n = 13 M = -9.2 SD = 4.4 |
Surgical intervention Le Fort I + BSSO BSSO | n = 21 n = 5 |
Surgical movements Sagittal translation maxilla, mm | M = 2.82 SD = 2.2 |
Vertical translation maxilla, mm | M = 1.76 SD = 1.3 |
Transversal translation maxilla, mm | M = 0.95 SD = 0.9 |
Sagittal translation mandibula, mm | M = 4.13 SD = 2.83 |
Vertical translation mandibula, mm | M = 2.42 SD = 1.58 |
Transversal translation mandibula, mm | M = 1.48 SD = 1.27 |
Roll maxillomandibular complex, ° | M = 0.62 SD = 0.85 |
Pitch maxillomandibular complex, ° | M = 1.58 SD = 2.48 |
Yaw maxillomandibular complex, ° | M = 0.73 SD = 1.04 |
4D motion capture
Facial expressions
Pre-surgical T0 | Post-surgical T1 | ||||||
---|---|---|---|---|---|---|---|
95% CI | 95% CI | ||||||
Mean | Lower | Upper | Mean | Lower | Upper | p | |
Maximum smile | |||||||
Magnitude, mm | 15.24 | 13.07 | 17.4 | 17.27 | 15.1 | 19.44 | 0.002 |
Shape change, mm | 0.03 | 0.01 | 0.05 | 0.05 | 0.03 | 0.07 | 0.122 |
Symmetry, mm | 0.99 | 0.52 | 1.46 | 1.78 | 1.31 | 2.25 | 0.024 |
Time, s | 0.41 | 0.36 | 0.45 | 0.43 | 0.39 | 0.47 | 0.41 |
Lip purse | |||||||
Magnitude, mm | 9.34 | 8.43 | 10.25 | 8.31 | 7.4 | 9.22 | 0.01 |
Shape change, mm | 0.022 | 0.019 | 0.026 | 0.02 | 0.017 | 0.024 | 0.19 |
Symmetry, mm | 1.27 | 0.88 | 1.66 | 1.06 | 0.67 | 1.45 | 0.38 |
Time, s | 0.36 | 0.33 | 0.39 | 0.32 | 0.29 | 0.35 | 0.052 |
Pre-surgical T0 | Post-surgical T1 | ||||||
---|---|---|---|---|---|---|---|
95% CI | 95% CI | ||||||
Mean | Lower | Upper | Mean | Lower | Upper | p | |
Skeletal class II Maximum smile | |||||||
Magnitude, mm | 15.67 | 12.61 | 18.74 | 17.67 | 14.61 | 20.73 | 0.1 |
Shape change, mm | 0.031 | 0.002 | 0.06 | 0.067 | 0.04 | 0.097 | 0.23 |
Symmetry, mm | 0.89 | 0.23 | 1.55 | 1.78 | 1.12 | 2.44 | 0.25 |
Time, s | 0.42 | 0.36 | 0.48 | 0.42 | 0.36 | 0.48 | 1 |
Skeletal class III Maximum smile | |||||||
Magnitude, mm | 14.8 | 11.74 | 17.87 | 16.87 | 13.8 | 19.93 | 0.09 |
Shape change, mm | 0.032 | 0.003 | 0.062 | 0.308 | 0.009 | 0.067 | 0.99 |
Symmetry, mm | 1.09 | 0.42 | 1.75 | 1.78 | 1.12 | 2.45 | 0.46 |
Time, s | 0.39 | 0.33 | 0.45 | 0.44 | 0.38 | 0.49 | 0.58 |
Skeletal class II Lip purse | |||||||
Magnitude, mm | 8.76 | 7.47 | 10.04 | 7.67 | 6.38 | 8.95 | 0.18 |
Shape change, mm | 0.02 | 0.01 | 0.025 | 0.02 | 0.012 | 0.023 | 0.77 |
Symmetry, mm | 1.22 | 0.67 | 1.77 | 1.32 | 0.77 | 1.87 | 0.99 |
Time, s | 0.38 | 0.34 | 0.42 | 0.31 | 0.27 | 0.36 | 0.12 |
Skeletal class III Lip purse | |||||||
Magnitude, mm | 9.92 | 8.63 | 11.2 | 8.96 | 7.67 | 10.24 | 0.27 |
Shape change, mm | 0.025 | 0.02 | 0.03 | 0.024 | 0.018 | 0.029 | 0.79 |
Symmetry, mm | 1.31 | 0.76 | 1.87 | 0.8 | 0.25 | 1.35 | 0.42 |
Time, s | 0.34 | 0.3 | 0.39 | 0.32 | 0.28 | 0.37 | 0.94 |
Estimate | Std. error | t value | p | |
---|---|---|---|---|
(Intercept) | 4.53 | 3.15 | 1.44 | 0.173 |
Sagittal translation maxilla | 0.23 | 0.48 | 0.48 | 0.637 |
Vertical translation maxilla | − 0.29 | 0.79 | − 0.37 | 0.719 |
Transversal translation maxilla | − 0.54 | 1.14 | − 0.47 | 0.645 |
Sagittal translation mandibula | − 0.09 | 0.34 | − 0.27 | 0.793 |
Vertical translation mandibula | − 0.27 | 0.53 | − 0.51 | 0.619 |
Transversal translation mandibula | − 0.21 | 0.77 | − 0.27 | 0.792 |
Roll maxillomandibular complex | 0.54 | 0.97 | 0.55 | 0.588 |
Pitch maxillomandibular complex | 0.61 | 0.5 | 1.22 | 0.242 |
Yaw maxillomandibular complex | − 1.36 | 0.99 | − 1.37 | 0.191 |
Skeletal class | − 0.47 | 1.54 | − 0.30 | 0.766 |
Type of surgical intervention | − 4.43 | 2.16 | − 2.04 | 0.060 |
Estimate | Std. error | t value | p | |
---|---|---|---|---|
(Intercept) | − 1.92 | 2.41 | − 0.8 | 0.438 |
Sagittal translation maxilla | 0.22 | 0.37 | 0.61 | 0.553 |
Vertical translation maxilla | − 0.39 | 0.61 | − 0.64 | 0.534 |
Transversal translation maxilla | − 0.73 | 0.87 | − 0.84 | 0.416 |
Sagittal translation mandibula | − 0.08 | 0.27 | − 0.29 | 0.775 |
Vertical translation mandibula | 0.37 | 0.41 | 0.91 | 0.383 |
Transversal translation mandibula | 0.19 | 0.59 | 0.33 | 0.746 |
Roll maxillomandibular complex | 0.91 | 0.74 | 1.23 | 0.239 |
Pitch maxillomandibular complex | 0.18 | 0.38 | 0.48 | 0.639 |
Yaw maxillomandibular complex | − 0.22 | 0.76 | − 0.29 | 0.776 |
Skeletal class | − 0.04 | 1.17 | − 0.03 | 0.977 |
Type of surgical intervention | 0.63 | 1.65 | 0.38 | 0.707 |