Obstructive sleep apnea and mandibular advancement splints: occlusal effects and progression of changes associated with a decade of treatment.

Study Objectives: To evaluate the magnitude and progression of dental changes associated with long-term mandibular advancement splint (MAS) treatment of obstructive sleep apnea (OSA).

Methods: Retrospective study of adults treated for primary snoring or mild to severe OSA with MAS for a minimum of 8 years. The series of dental casts of patients were analyzed with a digital caliper for changes in overbite, overjet, dental arch crowding and width, and inter-arch relationships. The progression of these changes over time was determined and initial patient and dental characteristics were evaluated as predictors of the observed dental side effects of treatment.

Results: A total of 77 patients (average age at start of treatment: 47.5 ± 10.2 years, 62 males) were included in this study. The average treatment length was 11.1 ± 2.8 years. Over the total treatment interval evaluated there was a significant (p < 0.001) reduction in the overbite (2.3 ± 1.6 mm), overjet (1.9 ± 1.9 mm), and mandibular crowding (1.3 ± 1.8 mm). A corresponding significant (p < 0.001) increase of mandibular intercanine (0.7 ± 1.5 mm) and intermolar (1.1 ± 1.4 mm) width as well as incidence of anterior crossbite and posterior open bite was observed. Overbite and mandibular intermolar distance were observed to decrease less with time, while overjet, mandibular intercanine distance, and lower arch crowding all decreased continuously at a constant rate.

Conclusions: After an average observation period of over 11 years, clinically significant changes in occlusion were observed and were progressive in nature. Rather than reaching a discernible end-point, the dental side effects of MAS therapy continue with ongoing MAS use.

Commentary: A commentary on this article appears in this issue on page 1293.