The Reliability of a Surgery-first Orthognathic Approach Without Presurgical Orthodontic Treatment for Skeletal Class III Dentofacial Deformity

Background: Orthognathic surgery with presurgical and postsurgical orthodontic treatment is the most widely accepted method for the correction of skeletal or dentoalveolar malocclusion. However, recent advancements in presurgical orthodontic simulations and postsurgical orthodontic treatments using miniscrews have shown remarkable stability and control of the occlusion after orthognathic surgery. Thus, we have adopted a surgery-first orthognathic approach without presurgical orthodontic treatment, based on a novel presurgical simulation process using a dental model. We hypothesized that this treatment modality will be feasible for skeletal class III dentofacial deformity patients.

Materials And Methods: This prospective study investigated intervention outcomes in 24 standard and 32 surgery-first approaches for patients with skeletal class III dentofacial deformity. The patients underwent orthognathic surgery between December 2007 and July 2010. In the surgery-first approach, a dental model was created and a novel preoperative orthodontic simulation of the standard presurgical orthodontic treatment was performed to determine the final occlusion between the maxilla and mandible. Changes in cephalometric landmarks were compared between the standard and surgery-first groups in the preoperative, immediate postoperative, and postoperative periods. The Student t test, Kruskal-Wallis test, and a linear mixed model were used for statistical analysis.

Results: The follow-up period ranged from 12 to 36 months (average, 20.5 months). The average age of the patients was 22.4 years, with 16 male and 40 female patients. We found that a surgery-first approach without presurgical orthodontic treatment is possible and can give similar results to standard orthognathic surgery. The statistical analysis showed that changes in skeletal cephalometric landmarks were similar between the surgery-first and standard approach groups, according to each period. However, the cephalometric landmarks relating to the dental component showed changes between treatment groups at different time points but similar final values. This suggests that the benefits of postsurgical orthodontic treatment after the surgery-first approach could be similar to those obtained via the standard approach.

Conclusions: The surgery-first orthognathic approach without presurgical orthodontic treatment was found to be predictable and applicable to treat class III dentofacial deformities, and we recommend consideration of the technique as an effective alternative for treating this condition.