Evaluation of the effect of skeletal sagittal malocclusions to smile with 3D face imaging method

The aim of this research is to analyse face soft tissue values of patients who have different skeletal sagittal malocclusions with 3D face imaging method during resting and smiling and evaluate changes that occur while passing from rest to smile positions. In our study, there are 3 groups including skeletal Class I, Class II and Class III malocclusions. Each group consists of 30 patients with age between 14-25. 3D stereophotogrametric images of 90 patients were obtained during resting and social smiling positions. Linear, angular and proportional measurents were made with these 3D images. According to the data of our study, rest and smile lower lip length, soft tissue convexity angle and upper lip angle were found higher in skeletal Class III patients. Smile lower lip angle, resting nose tip protrusion angle, and incisor's teeth appearance amount were lower in skeletal Class III patients. During transition from rest to smile position, significant changes occurred in soft tissues. In all groups, there is a decrease in lower lip and nasal tip clarity angle, while other angular values increase. During smiling, nasal, filtration and mouth width increased in all groups but upper lip length, upper lip vermillion length, lower lip length and lower lip vermillion length decreased. Significant changes in soft tissues occurred from rest to smile position during imaging. 3D stereophotogrammetry method is fast, reliable and doesn't contain radiation and also allows researcher to take repetitive images in short time intervals.