Cephalometric study of the position of ala-tragus line in relation to Frankfort horizontal plane and occlusal plane among Ludhiana population

Abstract

Introduction: The inclination of occlusal plane (OP) is determined by paralleling the OP to ala-tragus line. Inspite of its wide acceptability, the exact location of tragal point on ala-tragus line is unclear. In addition, morphologic features vary among various ethnic groups. Therefore, it is important to evaluate the exact reference point on tragus among Ludhiana population. Aim: The aim of this study is to determine the posterior reference point of the ala-tragus line that forms the most parallel line with the natural OP among Ludhiana population. Methodology: Digital lateral cephalograms were taken in 100 dentulous Angle's Class I subjects of 18–30 age group. Stainless steel balls were attached to ala of the nose (A) and three points that corresponded to superior (S), middle (M), and inferior (I) points on the tragus of ear. The angle formed by each line (SA, MA, and IA planes) with Frankfort horizontal (FH) plane and OP were measured on all tracings of cephalograms. Results: The mean angular value of IFH (angle between IA-FH planes) was the closest to the Cant of OP, and the mean angular value of IOP (angle between IA plane and OP plane) was the least compared to angles MOP (angle between MA-OP planes) and SOP (angle between SA-OP planes). Conclusion: The inferior point marked on tragus is the most appropriate point for marking ala-tragus line among Angle's Class I subjects of Ludhiana.

Keywords

• Ala-tragus line
• cant of occlusal plane
• Frankfort horizontal plane
• occlusal plane
• tragus