Objective: To evaluate vertical stability after various orthognathic surgical treatment plans for skeletal class Ⅲ malocclusion with anterior openbite.
Methods: A retrospective multicenter cohort study was conducted to investigate vertical stability after various orthognathic surgical treatment plans for skeletal class Ⅲ malocclusion with anterior openbite. From 2010-2016, 122 patients from two domestic stomatological hospitals were included in our study. Patients were divided into four groups according to their treatment plans, namely, bilateral sagittal split ramus osteotomy (BSSRO), intraoral vertical ramus osteotomy (IVRO), BSSRO+Le Fort Ⅰ, and IVRO+Le Fort Ⅰ. All patients followed a standardized examination procedure at 6 and 24 months post-treatment. The observation indexes include overbite, mandibular plane angle, and intermaxillary angle.
Results: 1) The significantly reduced ratio of the overbite in the BSSRO+Le Fort Ⅰ and IVRO+Le Fort Ⅰ groups were less than the BSSRO and IVRO groups at 6 and 24 months post-treatment. 2) The significantly increased ratio of the mandibular plane in BSSRO+Le Fort Ⅰ and IVRO+Le Fort Ⅰ groups were less than BSSRO and IVRO groups at 6 and 24 months post-treatment. 3) The significantly increased ratio of the intermaxillary angles in BSSRO+Le Fort Ⅰ and IVRO+Le Fort Ⅰ groups were less than the BSSRO and IVRO groups at 6 months post-treatment, while there was no statistical difference at 24 months post-treatment.
Conclusions: Bimaxillary surgery (BSSRO+Le Fort Ⅰ and IVRO+Le Fort Ⅰ) is more effective than mandibular surgery to control vertical relapse.
目的 比较不同正颌外科手术方案对骨性Ⅲ类错伴前牙开术后垂直向稳定性的影响。方法 收集入院接 受手术的骨性Ⅲ类错伴前牙开畸形患者122例，分别采用双侧下颌升支矢状劈开（BSSRO）（50例）、下颌升支 垂直骨劈开（IVRO）（30例）、BSSRO+Le FortⅠ（22例）、IVRO+Le FortⅠ（20例）作为手术方案，并且除IVRO方案外其他所有方案病例均接受钛板颌骨内坚固内固定术。术后正畸完成时及完成后6、24个月时随访接受临床检查与头影测量分析评估垂直向复发情况，观察指标包括覆、下颌平面角、颌间夹角。结果 1）BSSRO+Le FortⅠ与 IVRO+ Le FortⅠ组覆显著减小的比率在6、24个月都少于BSSRO与IVRO组。2）BSSRO+Le FortⅠ组与IVRO+ Le FortⅠ组下颌平面角显著增加的比率在6、24个月都少于BSSRO与IVRO组。3）6个月时BSSRO+Le FortⅠ组与IVRO+ Le FortⅠ组颌间夹角显著增加的比率少于BSSRO组与IVRO组，而24个月时无统计学差异。结论 双颌外科（BSSRO+ Le FortⅠ与IVRO+Le FortⅠ）均比单颌外科（BSSRO与IVRO）能更加有效地减少垂直向复发的数量和幅度。.
Keywords: intermaxillary angle; mandibular plane angle; open bite; orthognathic surgery; overbite; skeletal class Ⅲ malocclusion.