# Association between mouth opening pattern and facial skeletal pattern: a retrospective analysis

## TL;DR

This study explores how mouth opening varies with facial skeletal patterns and sex in a southern Italian population.

## Contribution

It identifies sex and vertical growth pattern as significant factors influencing mouth opening.

## Key findings

- Men open their mouths more than women on average.
- Hyperdivergent individuals open their mouths less than hypodivergent and normodivergent individuals.
- Sex and vertical growth pattern significantly influence mouth opening.

## Abstract

The aim of the present study was to investigate the relationship between mouth opening pattern and facial skeletal pattern in a southern Italian population.

This retrospective study included 415 subjects. The sagittal skeletal pattern was classified in Class I, II, and III according to ANPg angle and the vertical growth pattern was classified as hypodivergent, normodivergent, and hyperdivergent according to SNGoGn angle. Maximum mouth opening (MM0) records and 20% and 80% of these values in the normal distribution curve were considered for analysis purposes.

The median age was 23 years (IQR, 20-28), and the mean MMO was 52.1 mm (SD: 6). There was a statistical difference regarding the mouth opening according to sex (P:0.01) and vertical growth pattern (P: 0.02). The post hoc test (Tukey) showed men (53.6 mm) (SD 6.43) open the mouth more than women (51.4 mm) (SD 5.72), and hyperdivergent patients (50.6 mm) open less than hypodivergent (52.8 mm) and normodivergent (52.5 mm). The 2-way ANOVA tests regarding the low and high mouth opening patterns confirmed the previous findings of the general sample.

sex and vertical growth pattern seem to influence the amount of mouth opening.