Tooth contacts at the mandibular retruded position, comparison of two different methods for bite registration

Occlusal conditions at the retruded contact position (RCP) have been thought to be among the aetiological factors for temporomandibular disorders. However, the role of these occlusal factors remains still unclear. The purpose of this series of studies was to investigate the locations of RCP contacts and to discuss their meaning. In this part of the study, two different methods for bite registration at the RCP have been compared. Twenty dentists were selected as subjects for this study. One expert operator moved the subject's mandible up and down while guiding it gently backward until rotating on its retruded axis. Once the initial tooth contacts were established, the operator checked them using a thin articulating paper (direct method). Silicone-based impression material was used for bite registration while the subject kept the jaw at this contact position (indirect method). Differences between the two registration methods regarding locations of tooth contacts were evaluated. Results from the direct method showed that tooth contact at the first premolar was most frequently observed. Statistical difference was not shown between the two registration methods regarding locations of RCP contacts.