The relationship of occlusal disharmonies and symptoms of temporomandibular disorders

Abstract

Introduction: The influence of occlusal condition on the onset of temporomandibular disorder (TMD) has been strongly debated for many years and is still the source of controversy. Until 1980s, the occlusal factors such as the presence of uncured malocclusions, discrepancies between intercuspal position (ICP) and retruded contact position (RCP) greater than two millimeters, occlusal abnormality, particularly mediotrusion and retrusion, and loss of posterior teeth were considered the primary causes of TMD. Objective: The objective of our study was to find correlation of occlusion disharmonies (difference between ICP and RCP) and present sings and symptoms of TMD. Method: The study involved 60 subjects between 18 and 26 years of age who were divided in two groups. The study group consisted of 30 subjects between 18 and 26 years of age with sings and symptoms of temporomandibular disorders (TMD). TMD was confirmed according to Helkimo index. An average value of Helkimo index in this group was 1. The control group included 30 subjects between 20 and 25 years of age without TMD sings and symptoms. An average value of Helkimo index in this group was 0. The function analysis of cinematic centers position in RCP and ICP was performed in each subject using the computer pantograph Arcus-Digma (KaVo EWL GmbH, Leutkirch, Germany). Results: The results of our study showed that the translation tracing of cinematic points from RCP to ICP was significantly different in TMD subjects and asymptomatic group (p>0.16). In addition, the study revealed that 53.4 % of subjects with sings and symptoms of temporomandibular disorders had marked translation in the lower temporomandibular joint (0.61-1.2 mm) what directed to intracapsular disorders. Conclusion: The results of our study suggested significant difference of RCP and ICP between subjects with sings and symptoms of the temporomandibular disorders and subjects without sings and symptoms.