Stability of clockwise rotation of the maxillary occlusal plane in skeletal Class III patients treated with two‐jaw surgery

• Published in: Orthodontics & craniofacial research Vol. 26; no. 2; pp. 207 - 215
• Main Authors: Kang, Soon‐Young, Kim, Young Ho, Baek, Seung‐Hak, Kim, Dong Woo, Shin, Jeong Won, Chae, Hwa Sung
• Format: Journal Article
• Language: English
• Published: England Wiley Subscription Services, Inc 01.05.2023
• Subjects: Cephalometry; Dental Occlusion; Female; Humans; Jaw; Male; Malocclusion, Angle Class III - surgery; Mandible; Maxilla; Maxilla - surgery; Orthognathic Surgical Procedures; Osteotomy; Osteotomy, Le Fort; Recurrence; relapse; Retrospective Studies; Rotation; Surgery; the maxillary rotation; two‐jaw orthognathic surgery; two-jaw orthognathic surgery; relapse; the maxillary rotation
• ISSN: 1601-6335; 1601-6343
• DOI: 10.1111/ocr.12601

Objective The objective of the study was to investigate the post‐surgical stability of clockwise rotation of the maxillary occlusal plane (MXOP) after Le Fort I osteotomy for posterior impaction and advancement, in skeletal Class III patients who had undergone two‐jaw orthognathic surgery (2J‐OGS). Materials and Methods The sample set consisted of 46 patients (18 males and 28 females). Using lateral cephalograms taken at the initial evaluation (T0), before 2J‐OGS (T1), after 2J‐OGS (T2) and at debonding (T3), the amount of MXOP change (criterion: 2° in ΔMXOP [between T2 and T3]) was used to assign patients to Group 1 (G1, high relapse, −3.09°) or Group 2 (G2, low relapse, −0.99°). Findings were statistically compared between the groups. Results Compared with G2, G1 exhibited more severe skeletal Class III relationships and a flatter MXOP at T0, a greater increase in ΔANB, and more clockwise rotation of ΔMXOP and ΔFMA between T1 and T2. G1 also showed a greater decrease in ΔANB, higher counterclockwise rotation of ΔMXOP and upward movement of U1 between T2 and T3. Regression analysis yielded the following equation: MXOP (ΔT2‐T3) = −0.37 X MXOP (ΔT1‐T2) −0.43. Conclusions The higher the clockwise rotation of the MXOP during 2J‐OGS in skeletal Class III patients, the greater the subsequent relapse (counterclockwise rotation) of the MXOP.