The effect of head posture on facial soft tissue changes captured by white-light facial scanning
Published Online: Jul 20, 2021
Page range: 134 - 142
Received: Aug 01, 2018
Accepted: Jun 01, 2019
DOI: https://doi.org/10.21307/aoj-2020-042
© 2019 Jae-Beom Lim et al., published by Sciendo
This work is licensed under the Creative Commons Attribution 4.0 International License.
Objective
To investigate whether changes in head posture have significant effects on facial soft tissues during white-light scanning.
Materials and methods
Thirty-four adult patients participated in the study in which 22 soft tissue landmarks were marked on the face of each subject using an oil-based pen. The subjects wore digital inclinometers on top of their heads, and sat relaxed with their heads orientated in natural head position (NHP), while a facial scan was captured. The subjects underwent a second facial scan in an upward 5°(U5), upward 10°(U10), downward 5°(D5), or a downward 10°(D10) direction with respect to the NHP. The NHP image was superimposed on the images taken at the different head postures and a single co-ordinate system was obtained. The axial reference plane (x-axis), the sagittal reference plane (y-axis) and the coronal plane (z-axis) were set with N’ as the zero point (0, 0, 0). The changes in position of each landmark caused by the change of head posture were measured.
Results
When the subject’s head was in the U5 and D5 posture, changes in landmark identification were not statistically significantly different. When the subject’s head was in the U10 posture, soft tissue Stmi and Li moved downward significantly. Soft tissue pogonion moved forward significantly in the D10 posture.
Conclusions
Soft tissue changes within 5° of the natural head posture were clinically negligible. If efforts to reproduce natural head position are carried out, reliable facial scanning images can be obtained without the support of any special head positioning tools.