The Effect of Patient Position on Recording the Centric Relation of Occlusion by Tracing the Gothic Arch in Edentulous Patients

Recording the maxillomandibular relation is one of the important procedures in prosthodontic treatments. The centric relation (CR) of occlusion is the most important of these records. Body posture of the patient is one of the factors influencing the CR. In this study, we investigated the influence of patient's body position in CR recording by extra-oral tracing method. In this cross-sectional study, 18 edentulous Patients were randomly selected. After patient education, the extra-oral tracing device was attached to patient's dentures. Then the Gothic arch tracing was accomplished in supine, semi supine and upright position. The CR achieved by bimanual manipulation method was also recorded. Then the horizontal, anterior-posterior and straight distances of each point to point achieved by Dawson method, were calculated. Data were statistically analyzed using the one-way ANOVA and t-test. The level of significance was set at 95%. In edentulous subjects, there was no significant difference between horizontal distances of points registered in various body positions and the point registered in Dawson method, but with a view to ant-post and direct distances, the points registered in supine position were significantly nearer to that of Dawson method rather than the points registered in upright position. In edentulous subjects, and in comparison to upright position, the CR obtained in supine position by extraoral tracing method, was significantly similar to bimanual manipulation.