# Influence of vertical growth pattern on masseter muscle morphology: evidence from cephalometric and ultrasound assessment in eighteen growing subjects

## TL;DR

This study shows that vertical facial growth affects the masseter muscle's structure, which could help improve orthodontic treatments for growing patients.

## Contribution

The study provides new evidence linking vertical facial dimensions to masseter muscle morphology using combined cephalometric and ultrasound assessments.

## Key findings

- Subjects with increased vertical facial dimensions had reduced masseter muscle thickness and volume.
- Vertical cephalometric indices like SN-GoGn and FMA were significantly correlated with ultrasonographic parameters of the masseter.
- Ultrasonographic assessment combined with cephalometric analysis offers clinically relevant insights for orthodontic diagnosis.

## Abstract

The relationship between vertical facial dimensions and morphological-functional features of the masseter muscle in growing patients is of increasing interest in orthodontics. Understanding these correlations may enhance diagnostic accuracy and guide treatment planning, particularly in subjects with altered vertical skeletal patterns.

Growing patients underwent two-dimensional cephalometric analysis and ultrasonographic evaluation of the masseter muscle. Cephalometric variables included SNA, SNB, ANB, SN-GoGn, FMA, AFH, and Go–Me, while ultrasonographic parameters comprised thickness, cross-sectional area (CSA), and volume of the masseter, both at rest and during contraction. Correlations were assessed using Pearson's coefficient, and multiple linear regression was applied to identify predictive associations. A p-value < 0.05 was considered statistically significant.

A significant correlation was found between vertical growth pattern and ultrasonographic characteristics of the masseter. Subjects with increased vertical facial dimensions exhibited reduced muscle thickness and volume (p < 0.05). Regression analysis confirmed associations between vertical cephalometric indices (SN-GoGn, FMA) and ultrasonographic parameters, with R2 values ranging from 0.30 to 0.45.

Findings suggest that vertical skeletal pattern influences masseter morphology, highlighting the role of masticatory musculature in craniofacial development and vertical discrepancies.

Integrating ultrasonographic assessment of the masseter with cephalometric analysis may provide clinically relevant insights for orthodontic diagnosis and management in growing patients.