# Tooth shape asymmetry in post-canine dentition: Evidence-based morphometric insights

## TL;DR

This study examines tooth shape asymmetry in the post-canine dentition of young patients and finds significant differences between left and right sides.

## Contribution

The study provides morphometric evidence of dental asymmetry and its sex-related variations in post-canine teeth.

## Key findings

- 20–30% of principal components explained 80% of shape variation in tooth landmarks.
- Significant shape differences were observed in most teeth except the 3-cusp mandibular second premolar.
- Asymmetry was more prevalent in specific premolar and molar types across dental arches.

## Abstract

This study investigates the potential existence of asymmetry in the shape of tooth and location of landmarks of tooth anatomy and its variation between sexes.

Our study evaluated dental symmetry in 160 patients aged 13–20 years, focusing on post-canine dentition. Using 3D geometric morphometrics, the research evaluated the variations in the anatomical landmarks between left and right side.

Analysis of the landmarks revealed that 20–30 % of the principal components explained 80 % of the shape variation. No significant difference in centroid size was found between sexes, but significant shape differences were noted in all teeth except the 3-cusp type mandibular second premolar. Asymmetry was more in the premolar segment in the maxillary arch and in the two-cusp type of mandibular second premolar and the mandibular first molar in the mandibular arch.

The research underscores the evolutionary advantage of bilateral symmetry and the presence of fluctuating asymmetry, possibly linked to genetic or environmental stressors. It emphasizes the importance of understanding dental asymmetry for effective treatment planning and diagnosis, in restorative dentistry and orthodontics.

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