# Skeletal and non-skeletal factors associated with mandibular asymmetry in mixed dentition

## TL;DR

This study identifies skeletal and non-skeletal factors linked to jaw asymmetry in children with mixed dentition.

## Contribution

The study provides new insights into factors influencing mandibular asymmetry during mixed dentition.

## Key findings

- Mandibular body asymmetry is associated with age ranges.
- Increased vertical growth and loss of the lower first molar increase the likelihood of mandibular ramus asymmetry.
- A bird's beak condyle shape and closed gonial angle are linked to mandibular body asymmetry.

## Abstract

Mandibular asymmetry is a complex challenge during mixed dentition. Aim: To determine the skeletal and non-skeletal factors associated with mandibular asymmetry in patients with mixed dentition.

The observational and cross-sectional study included 271 digital panoramic and lateral skull radiographs of patients from radiographic centers. The Eagle.PS Plate Scanner program was used to evaluate condylar morphology, lower second molar development, lower first molar loss, cervical vertebrae maturation, gonial angle, vertical growth, cranial base angle, intermaxillary relationship, and asymmetry. Frequencies, Spearman's Rho coefficient, Chi-square, and binomial logistic regression were used.

57.1% of patients were female, 61.3% were aged between 6 and 9 years, and 30% were at CS4 stage. Mandibular body asymmetry is related to age ranges (p=0.011). Patients with increased vertical growth (p=0.037; OR=3.20) and loss of the lower first molar (p=0.016; OR=11.33) are more likely to have mandibular ramus asymmetry; however, patients with an open cranial base angle are less likely to have it (p=0.039; OR=0.25). On the other hand, patients with a closed gonial angle (p=0.024; OR=3.48) and a bird's beak mandibular condyle shape (p=0.046; OR=2.68) are more likely to have mandibular body asymmetry.

Asymmetry in mandibular body is associated with the age, while a decreased gonial angle and a bird-beak condyle shape predispose to asymmetry in mandibular body height. An increased vertical growth pattern and the loss of the first permanent lower molar predispose to asymmetry in mandibular ramus height, while an increased cranial angle is associated with a lower probability.