Comparison of three dimensional stereophotogrammetric and cephalometric measurements

Temur Pekgöz, B. (2024) Comparison of Three Dimensional Stereophotogrammetric and Cephalometric Measurements, Yeditepe University Institute of Health Sciences, Department of Orthodontics, PhD thesis, Istanbul. The aim of this study was to analyse the facial soft tissues of individuals with different skeletal malocclusions and different growth directions on cephalometric and 3dMD images and to evaluate the differences between cephalometric and 3dMD images and the effects of skeletal malocclusions and growth directions on soft tissues at 3dMD images. There were 9 groups in present study. These groups were Class I hypodivergent, Class I normodivergent, Class I hyperdivergent, Class II hypodivergent, Class II normodivergent, Class II hyperdivergent, Class III hypodivergent, Class III normodivergent, Class III hyperdivergent. Each group consisted of 10-11 individuals over 14 years of age. A total of 93 individuals were evaluated by 3dMD method in resting position. In the statistical analysis, Shapiro-Wilk test was used to determine the distribution of variables, one-way analysis of variance was used for variables with normal distribution, Tukey multiple comparison test was used for subgroup comparisons, Kruskal Wallis test was used for variables without normal distribution, and Dunn's multiple comparison test was used for subgroup comparisons. A statistically significant difference was found between cephalometric and 3dMD measurements in the parameters of lower facial height, mid-facial height and anterior facial height (p<0,001). However, this difference was not clinically significant. The parameters of lower facial height and anterior facial height were found to differ according to the growth direction. Additionally, differences were observed in the nasolabial angle, total facial convexity angle, soft tissue convexity angle, H angle, labiomental angle, upper and lower lip prominence, and chin prominence parameters according to skeletal malocclusions. Individuals with hypodivergent and hyperdivergent growth patterns exhibit differences in facial heights and vertical measurements; in individuals with Class II and Class III skeletal malocclusions, differences in soft tissue convexity angle, total facial convexity angle, nasolabial angle, nasomental angle, H angle, lower lip prominence, upper lip prominence, and chin prominence parameters should be considered during treatment planning. Although there are statistically significant differences between cephalometric and 3dMD measurements in some parameters, these differences are clinically insignificant. The 3dMD system can be used safely in anthropometric and norms studies.