# Investigating the relationship between the occlusal plane and the tragus-ala line in patients with different jaw skeletons

## TL;DR

This study explores how the occlusal plane relates to the ala-tragus line in patients with different jaw structures, finding that the lower ATL can be a useful reference for determining the occlusal plane.

## Contribution

The study identifies significant parallelism between the lower ATL and the occlusal plane in class 3 jaw patients and highlights the influence of age and gender.

## Key findings

- Significant parallelism between the lower ATL and the occlusal plane was observed in class 3 jaw patients.
- Age and gender were found to influence the relationship between the occlusal plane and the lower ATL.
- The lower ATL can serve as a reliable reference for determining the occlusal plane in certain jaw classifications.

## Abstract

This study investigated the relationship between the occlusal plane and the ala-tragus lines (ATL) for restoring the upper and lower jaws and analyzed the ATL in different jaw classifications.

This analytical cross-sectional study included lateral cephalometric radiographs of 172 patients with teeth in a normal position. The three ATLs and the occlusal plane were delineated, and jaw classification was determined using Waits and Steiner analysis.

For jaw classes 1 and 2, the parallelism between the lower ATL and the occlusal plane was not statistically significant. However, for class 3 patients, significant parallelism was observed between the lower ATL and the occlusal plane, regardless of the maxillary classification. In the gender-based analysis, the parallelism between the occlusal plane and the lower ATL was significant for women. In the age-based analysis, the parallelism was significant in the age group of 15–21 years.

These findings suggest that the lower ATL can be a reliable reference for determining the occlusal plane. The study also highlights that age and gender are important factors influencing the determination of the occlusal plane using the ATL.

Key words:Occlusal plan, ala-tragus line, cephalometric radiograph.