Evaluation of the Relationship between Upper and lower Occlusal Plane with Ala-Tragus and Retromolar Pad

Abstract

Statement of Problem: Orientation of the occlusal plan in complete denture prostheses therapies plays an important role, leading to appropriate esthetics, stability and mastication.Purpose: The aim of the present study was to define the best soft tissue index, by which the location and inclination of the occlusal plane in complete dentures could be established.Materials and Method: This cross-sectional study consisted of 200 individuals (76 male, 124 female), with the mean age of 26.05 (SD±4.39). In order to determine the relationship between maxillary occlusal plane and ala-tragus line, fox plane and J plane were used. The relationships between maxillary occlusal plane and ALT1 (ala-superior border of tragus), ALT2 (ala-mid-tragus) and ALT3 (ala-inferior border of tragus) were evaluated. In the lower jaw, the occlusal plane was evaluated with the line between the upper and middle parts (ret1) and that between the middle and lower part of retromolar pad (ret2). Data were analyzed by Chi-square test.Results: Evaluation of the difference between the number and percentage using Chi–square test ( p < 0.05) showed that there were significant differences between ALT1, ALT2, ALT3 (ALT3 < ALT2 <ALT1). In the lower jaw, there were significant differences between ret1 and ret2 (ret1 > ret2). Conclusion: Superior one third of the tragus and the upper and middle one third of the retromolar pad are suggested as a reference points for determining the posterior part of the occlusal plane in comparison with the middle and lower one third of the tragus and middle and inferior one third of the retromolarpad.Key words: Retromolar pad, Ala-tragus, Occlusal plane