[Evaluation of the three-dimensional stability using dental casts after orthognathic surgery]

The increasingly frequent use of orthognathic surgery raises several questions on the results of operations, the resulting morphological and functional modifications, and the long-term three dimensional stability of the arches after surgery. In order to answer these questions a study was carried out using pre- and postoperative casts of the arches in a group of patients to evaluate the three dimensional stability of the correction.

Thirty-nine patients with different forms of malocclusion were selected who had undergone orthognathodontic surgery at least one year earlier. Twenty-seven patients (69.2%) received postoperative orthodontic treatment, including 9 who had undergone lower jaw surgery (33.3%), 3 maxillary surgery (11.1%) and 15 undergoing combined surgery (55.6%). Twelve patients (30.8%) did not receive postoperative orthodontic surgery, including 2 who had undergone lower jaw surgery (16.6%), 5 maxillary surgery (41.7%) and 5 undergoing combined surgery (41.7%). The two-dimensional reproductions of dental casts were studied using electronic image processing. Five different techniques were used (Bolton, Lundström, Howes, Staley and Reinhardt) to evaluate the dental arches. The study also evaluated whether any difference in results could be ascribed to use or absence of pre or postoperative orthodontic treatment.

The results indicate that protocols and surgical techniques used produce dental arches that are three-dimensionally stable and the use of orthodontic treatment gives greater stability one year after surgery compared to cases treated with surgery alone.

Major maxillary surgery should always be considered when assessing the possible solutions to malocclusions in order to correct anomalous bone formation with a reduced risk of recidivation of the correction.