Evaluation of hard and soft tissues after Le Fort I surgery

Akdag, A. (2024). Evaluation of Hard and Soft Tissues After Le Fort I Surgery. Yeditepe University, Institute of Health Science, Department of Orthodontics, PhD thesis, Istanbul. The aim of this thesis were to evaluate the relationship between soft tissue and hard tissue changes in orthognathic surgery patients who underwent Le Fort I osteotomy. Twenty two indivuduals operated with this technique have been selected for this study without any congenital deformities. The patients' average age had been 26.86 years. Lateral cephalometric films and 3D stereophotogrammetric images were obtained from twenty two patients before and after treatment. Parameters for soft tissue and hard tissue measurements were determined. Measurements of 3D streophotogrammetric data were made with 3dMD Vultus software program. Changes of 2D films before and after treatment were evaluated with Dolphin program. NCSS statistical software program was used to evaluate the data. According to statistical evaluations, 2D hard tissue variables were evaluated before and after treatment and the SNA, ANB, N-perpendicular-A distance, and Pog-N perpendicular distance, Maxillary Depth, Upper/Lower Gonial Angle all increased after treatment. Mean Maxillary Height, Upper Gonial Angle, Lower Gonial Angle, FMA, SGn-FH, Occ/SN, PP-GoGn, and Cranio-Mx Base/SN-Palatal Plane were lower compared at the start during operation. When soft tissue measurements are analysed; the results showed no change in the mean Nasolabial Angle and mean Facial Convexity. Also, the results showed a negative correlation between SN-GoGn, Lower Gonial Angle and Facial Convexity Angle. Significant correlation has been observed between P-A Face Height and IMPA and Labiomental Angle in our study. A significant correlation has beeen observed between P-A Face Height and IMPA and Labiomental Angle. In the literature, there is no study evaluating the correlation between 2D soft tissue parameters and 3D soft tissue parameters. Key words: Stereophotogrammetry, Orthognathic Surgery, Maxillary Advancement, Class III Anamoly.