Surgical Occlusion Setup and Skeletal Stability of Correcting Cleft-Associated Class III Deformity Using Surgery-First Bimaxillary Surgery

BACKGROUND: This study aimed to assess the 3-dimensional quantitative characteristics of the surgical occlusion setup in surgery-first cleft orthognathic surgery, and to evaluate its influence on postsurgical skeletal stability. METHODS: This prospective study was composed of 35 patients with unilateral cleft lip and palate and class III deformity who consecutively underwent 2-jaw surgery with the surgery-first approach. Digitized dental models were analyzed to quantify the 3-dimensional characteristics of the final surgical occlusion setup. Cone-beam computed tomography was used to measure the 3-dimensional surgical skeletal movement and postsurgical skeletal stability. The correlation between skeletal stability and surgical occlusal contact or surgical skeletal movement was also evaluated. RESULTS: Patients treated with the surgical occlusion setup had a large incisor overjet and positive overbite, as well as buccal cross-bite and open bite on second molars. Occlusal contact on 3 segments was present in 51.4% of the patients, and the average number for tooth contact was 4.3 teeth. No correlation was found between maxillary or mandibular stability and surgical occlusal contact. However, a significant correlation was found between maxillary and mandibular stability and the surgical skeletal movement. CONCLUSIONS: The surgical occlusion for correction of cleft-associated class III deformity using the surgery-first approach was characterized by large overjet and positive overbite, along with posterior cross-bite and open bite. On average, there was occlusal contact on 4 to 5 teeth; half of surgical occlusion setups had contact on 3 segments. The postsurgical skeletal stability was related not to the surgical occlusal contact but to the surgical skeletal movement. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, III.