However, some of these studies are limited by a relatively short observation period, considering that MAS treatment may continue indefi nitely through a patient's lifetime.Previous studies examining effects over at least a 5-year treatment period have shown signifi cant decreases in overbite (OB)-the vertical overlap of the anterior teeth, and overjet (OJ)-the horizontal overlap of the anterior teeth, ranging from 0.6-1.91 mm and 0.6-1.24 mm, respectively, after long-term appliance use. [16][17][18] These studies also report various
BRIEF SUMMARYCurrent Knowledge/Study Rationale: Mandibular advancement splints are an effective treatment option for OSA patients, with changes to the dental occlusion as a common side effect. Due to the indefi nite nature of OSA treatment a clear understanding of the magnitude and progression of long-term occlusal changes is needed. Study Impact: With the longest observation period yet to be reported, the results from this study confi rm that long-term MAS treatment leads to signifi cant changes in occlusion for the majority of patients. These dental changes were found to be progressive in nature, and continue with ongoing MAS use.