Determination of Mandibular Center of Rotation and Assessment of Association between Cephalometric Indices and Its Location
نویسندگان
1 Professor of Orthodontics, Dentofacial Deformities Research Center, Research Institute for Dental Sciences, School of Dentistry, Shahid Beheshti University of Medical Sciences, Tehran, Iran
2 Resident, Department of Orthodontics, School of Dentistry, Shahid Beheshti University of Medical Sciences, Tehran, Iran
3 Department of Orthodontics, School of Dentistry, Shahid Beheshti University of Medical Sciences, Tehran, Iran
4 Department of Orthodontics, Nova Southeastern University, College of Dental Medicine, Fort Lauderdale, Florida, USA
doi
10.22034/ijo.2023.2001885.1112چکیده
Aim: Following maxillary impaction, the mandible rotates around a center. Inaccurate determination of mandibular rotation can profoundly affect orthognathic surgical treatment planning and final surgical outcomes. The present study determined the relationship between the cephalometric characteristics of candidates for maxillary impaction surgery using sagittal and vertical locations of the center of rotation of the mandible.Methods: In a descriptive and cross-sectional trial, 36 candidates were selected for LeFort I maxillary impaction surgery. Two lateral cephalograms were obtained in open and closed mouth positions. The center of rotation of the mandible was determined by the Reuleaux technique. Cephalometric measurements of the patients with the determined center of mandibular rotation locations (regions 1 and 4 of the coordinate axis) were made and the results were subjected to the Student's t-test.Results: The center of mandibular rotation was located in region 1 of the coordinate axis in 17 (50%) and in the 4th region of the coordinate axis in 17 (50%). Statistically significant differences were observed regarding MP-SN (P<0.006), CO-GO (P<0.006), and CO-GN (P<0.04) at the two regions of 1 and 4 for the center of rotation of the mandible in the coordinate axis.Conclusion: With the decreased length of the ramus and increased inclination of the plane, the center of rotation of the mandible tended to be situated in region 1 of the coordinate axis; with the increased length of the ramus and decreased inclination of the plane, the center of mandibular rotation tended to be located in region 4 of the coordinate axis.
