Effects of an increased vertical dimension of occlusion on facial soft tissue height

To evaluate the effect of increased vertical dimension of occlusion (VDO) on soft tissue height using 3D facial scanning.

Sixteen participants (10 female, 6 male; mean 30.6 ± 9.1 years) underwent baseline 3D facial scans at maximum intercuspation (SB) followed by a second scan (S0) to assess reproducibility. VDO was increased by 3 mm and 5 mm at the right central incisor for additional scans (S3, S5). SB was superimposed with S0, S3, and S5 to create color-coded 3D models (M0, M3, and M5). Sixteen facial regions were analyzed using 3D software and evaluated with a mixed-effects model. Comparisons were made between SB and each VDO increase, without comparison between S3 and S5.

A total of 768 facial regions were analyzed. Reproducibility was confirmed except for the right temporal region. Soft tissue height changes, along with increased intrasubject variability, were observed at pogonion, gnathion, and labrale inferius as well as in the buccal regions, masseter muscles, and eyebrows. Vertical increases occurred at gnathion and in the masseter muscles and eyebrows, while decreases were found at pogonion and labrale inferius as well as in the buccal regions. Asymmetries were noted in the masseter muscles and eyebrows. No significant changes were observed in the labrale superius, temporal regions, lower orbital rims, or temporal muscles.

Increasing VDO by 3 mm and 5 mm resulted in measurable changes in facial soft tissue height. 3D facial scanning proved to be a reliable method for detecting these adaptations.