3-D Comparison of the shape and position of the condyle before and after Class II correction

Sepideh Torkan

Purpose: The aims of this study were to assess the changes in the shape and position of the condyle in the fossa as well as its position relative to the cranial base before and after Class II correction with the Herbst appliance (HA) or headgear (HG), and to also compare any changes to matched Class I cases.

Methods: Patients were divided into four groups, Class II treated with HA and their matched Class I cases, as well Class II cases treated with HG and their matched Class I cases. CBCTs were obtained before and after treatment in all cases. A total of 122 condyles (left and right) from 61 patients were assessed. 242 landmarks were identified on the condyle and fossa, from which 3-D surface meshes were created. 7 relatively stable landmarks were recorded on the skull to assess the position of the condyle relative to cranial base. Length of the mandible was measured on laterals cephalograms rendered from CBCTs. Principal component, generalized Procrustes, and discriminant function analyses were used to assess shape and position changes.

Results: There were no significant changes in the position of the condyle relative to the cranial base before and after treatment. No significant differences were reported in the anteropostserior or vertical position of the condyle relative to the fossa (P=0.71 and P=079 respectively). There were significant changes in the shape of the condyles when Class II untreated cases were compared to controls. Untreated Class II cases had more internal rotation of the mediolateral long axis of the condyles when compared to Class I cases. There were no significant differences in changes in the length of the mandible between Class II and control cases.

Conclusions: The condyles of all untreated patients, whether they were Class I or Class II initially, did not change their position (within the fossa or relative to stable cranial base structures) when assessed at the end of orthodontic treatment.

Bio: Sepi grew up in Iran with her parents and her older brother and sister. She completed dental school in her hometown where she met her husband, Navid. Sepi became increasingly fascinated by orthodontics during her time in dental school. She started a 4-year orthodontics residency right after finishing dental school and worked as an orthodontist for 8 months before deciding to start a new journey and move to the United States. She was very fortunate to get into the school of her dreams; the University of Washington has given rise to a great number of her orthodontic idols. After two residencies and two countries, she is very excited for the next chapter of her life and is looking forward to starting a career as an orthodontist in Seattle where she now calls home. Sepi is proud to finally be in the ranks of UW alumni and is grateful for all the valuable lessons she has learned from her faculty. She would like to thank her husband, Navid, for his unwavering support and unconditional love. This day would not have come without him!