Effect of facial profile convexity on the perception of mandibular asymmetry using three dimensional stereophotogrammetric images

OBJECTIVE: The aim of this study was to test the hypothesis that sagittal anomalies have an effect on the perception of mandibular asymmetry. Secondly, it aimed to determine the asymmetry perception threshold of orthodontist and laypeople. SETTING AND SAMPLE POPULATION: A total of 90 individuals were included in the study from different professions (Orthodontist: n:45, layperson: n:45). MATERIALS & METHODS: The reference image was obtained with 3dMD device and selected from among the individuals with class I soft tissue relationship. In the sagittal direction, the chin area has been moved as to produce 5 and 10 degrees of change in facial convexity angle. Similarly, 0, 2, 4, 6, 8 and 10 mm changes were made and recorded in video format. Manipulated images were scored by participants with VAS method. RESULTS: When differences between the groups were evaluated, the reference image was scored similarly by orthodontists and layperson (P: .017). No statistically significant difference was observed between the groups in other parameters (P > .05). Asymmetry in 0-2 mm range was evaluated by orthodontist and layperson and statistically insignificant (P > .05). Similarly, the change between 8 mm and 10 mm was different in both groups and statistically insignificant (P > .05). Also, when there was no asymmetry, the sagittal direction was differently scored by the participants in both groups and statistically insignificant (P > .05). CONCLUSIONS: It was observed that the effect of sagittal direction changes on asymmetry perception was not statistically significant.