Reproducibility of the lip position at rest: A 3-dimensional perspective

Creative Commons License

Dindaroglu F. , DURAN G. S. , GÖRGÜLÜ S.

AMERICAN JOURNAL OF ORTHODONTICS AND DENTOFACIAL ORTHOPEDICS, vol.149, no.5, pp.757-765, 2016 (Journal Indexed in SCI) identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 149 Issue: 5
  • Publication Date: 2016
  • Doi Number: 10.1016/j.ajodo.2015.10.029
  • Page Numbers: pp.757-765


Introduction: In this study, we evaluated the reproducibility of the lip position at rest in 3 dimensions using reverse engineering software and stereophotogrammetric images. Methods: We used 3dMD Flex (3dMD, Atlanta, Ga) to obtain 60 stereophotogrammetric images from the same participant. Thirty images were obtained in 3 sessions on the same day, and the procedure was repeated 6 weeks later for 30 more images. The surface-base registration, the segmentation of the upper and lower lips, and the 3-dimensional deviation analysis were performed with Geomagic Control (3D Systems, Rock Hill, SC) software. The Shapiro-Wilk test, paired sample t test, Bland-Altman plots, and Wilcoxon signed rank test were used for statistical analysis at a significance level of P <0.05. Results: The deviations of the upper lip on the first images were between 0.16 and 1.39 mm. The mean total deviation was 0.25 +/- 0.12 mm. The mean deviation of the lower lip was 0.34 +/- 0.17 mm. The deviations were observed between -1.96 and 1.97 mm. When the mean positive (P = 0.633 and P = 0.171, respectively) and the mean negative (P = 0.771 and P = 0.842, respectively) deviations of the upper and lower lips were analyzed, there was no significant difference between the 2 time points. Conclusions: The results suggest that the rest position can be reproduced within a small range both on the same day and between the sessions. More research with larger samples is needed to confirm these results.