Changes in occlusal contact area during oral appliance therapy assessed on study models

Objective: To test the hypothesis that long-term use of an oral appliance (OA) does not cause changes in the occlusal contact area (OCA). Materials and Methods: Baseline and follow-up treatment study models were obtained for 45 patients with obstructive sleep apnea who had been using an CA for 4 or more days/week for more than 5 years. Study models in centric occlusion, with an inserted pressure-sensitive sheet, were loaded in compression. An image scanner was used to evaluate OCA. Results: A significant change in total OCA was identified in 39 patients (86.7%): a decrease in 26 (66.7%) and an increase in 13 (33.3%) patients. Regional changes > 5% were observed in > 90% of patients in each of the three regions. In the molar and premolar regions, 24 (53.3%) and 27 (60.0%) of the patients showed an OCA decrease, while only 16 (35.6%) and 15 (33.3%) showed an increase. Conversely, for the anterior region, more increases (24 patients-53.3%) than decreases were identified. Conclusion: The hypothesis is rejected. Long-term OA therapy resulted in dramatic changes of occlusion, suggesting that monitoring of occlusal changes is required.