Surgical occlusion setup and skeletal stability of correcting cleft-associated class III deformity using surgery-first bimaxillary surgery.

Abstract

This study aimed to assess the three-dimensional (3D) quantitative characteristics of the surgical occlusion setup in surgery-first cleft orthognathic surgery, and to evaluate its influence on post-surgical skeletal stability. This prospective study was comprised of 35 patients with unilateral cleft lip and palate and class III deformity who consecutively underwent two-jaw surgery with surgery-first approach. Digitized dental models were analyzed to quantify the 3D characteristics of the final surgical occlusion setup. Cone-beam computed tomography was used to measure the 3D surgical skeletal movement and post-surgical skeletal stability. The correlation between skeletal stability and surgical occlusal contact or surgical skeletal movement was also evaluated. The surgical occlusion setup had a large incisor overjet and positive overbite, and buccal cross bite and open bite on second molars. Occlusal contact on three 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. The surgical occlusion for correction of cleft-associated class III deformity using the surgery-first approach was characterized with large overjet and positive overbite, and posterior cross bite and open bite. On average, there was occlusal contact on four to five teeth; half of surgical occlusion setups had contact on three segments. The post-surgical skeletal stability was not related to the surgical occlusal contact but to the surgical skeletal movement.