A study of lower facial change according to facial type when virtually vertical dimension increases

Kim, Nam Woo; Lee, Gung Chol; Moon, Cheol Hyun; Bae, Jung Yoon; Kim, Ji Yeon

Abstract

PURPOSE
The aim of this study was to evaluate the effect of increased vertical dimension of occlusion on lower facial changes by facial type.
MATERIALS AND METHODS
Lateral cephalograms from 261 patients were obtained and classified by sagittal (Class I, II, and III) and vertical (hypodivergent, normodivergent, and hyperdivergent) facial patterns. Retrusive displacement of soft tissue Pogonion and downward displacement of soft tissue Menton were measured in each group after 2 mm of vertical dimension of occlusion was increased at the lower central incisor using a virtual simulation program. The ratio of both displacements was calculated in all groups. The statistical analysis was done by 2-way ANOVA and Post hoc was done by Tukey test (5% level of significance).
RESULTS
Retrusive displacement of soft tissue Pogonion in Class III group was statistically different compared to Class I and II, and in vertical facial groups all 3 groups were significantly different (P<.05). Downward displacement of soft tissue Menton showed statistically significant difference between all sagittal groups and vertical groups (P<.05). The ratio of both displacements showed statistically significant difference in all sagittal groups and vertical groups (P<.05), and Class II hyperdivergent group had the highest value.
CONCLUSION
Lower facial change was statically significant according to the facial type when vertical dimension of occlusion increased. Class II hyperdivergent facial type showed the highest ratio after increase in vertical dimension of occlusion.