Changes in functional occlusion during the postorthodontic retention period: A prospective longitudinal clinical study

IntroductionFunctional occlusion has received little attention in short- and long-term evaluations of orthodontic treatment results. Thus, the purpose of this study was to determine the long-term changes in functional occlusion during the postorthodontic retention period.MethodsOne hundred fifteen consecutive patients treated with multibracket appliances were examined twice: directly after appliance removal (T1) and after an average retention period of 24 months (T2). The clinical examination comprised the assessment of anteroposterior and lateral interferences (slides) between the retruded contact position and the intercuspal position and tooth contacts on protrusion and laterotrusion. Slides of 2 mm or more, posterior contacts on protrusion, and hyperbalanced contacts on laterotrusion were rated as unsatisfying functional occlusion.ResultsAt T1, 44.3% of the sample had an unsatisfying functional occlusion. At T2, this figure was 34.7%. In most subjects (72.3%), the functional occlusion ratings remained unchanged during the retention period (T1-T2). In 19.8% of the subjects, functional occlusion improved, whereas, in 7.9%, it became worse.ConclusionsSettling of the occluding teeth seems not to improve the functional occlusion after fixed appliance removal. Thus, it is necessary to check the functional occlusion before the appliance is removed to eliminate unsatisfying functional occlusal contacts.