ABSTRACT
The glossary of prosthodontic terms defines occlusal plane as an average plane established by the incisal and occlusal surfaces of the teeth. Generally, it is not a plane but represents the planar mean of the curvature of these surfaces. Another definition defines it as the surface of wax occlusion rims contoured to guide in the arrangement of denture teeth. Ala-tragus line according to the glossary of prosthodontic terms is defined as a line running from the inferior border of the ala of the nose to some defined point on the tragus of the ear, usually considered to be the tip of the tragus. It is frequently used, with a third point on the opposing tragus, for the purpose of establishing the ala-tragus plane. Ideally, the ala-tragus plane is considered to be parallel to the occlusal plane. The occlusal plane is at an angle of approximately 10 degrees relative to the Frankfort horizontal plane, when viewed in midsagittal plane. No precise, scientific method exists for determining the level of the occlusal plane in edentulous patients. Several principles have been postulated for determining the occlusal plane. The use of ala-tragus line to orient the occlusal plane has been controversial. This controversy is primarily due to disagreement on the exact point of reference for this line.Therefore the main objective of this study was to find out a reference line most parallel to the natural occlusal plane so that this reference point on the tragus can be used to determine the occlusal plane during the fabrication of complete denture