What is the correlation between thickness and anterior posterior width of masseter muscle in ultrasonography with intermolar width in maxilla and mandible?

Abstract

Background Knowledge of masseter muscle size can be helpful in choosing more successful and stable orthodontic treatment plans. This study aimed to evaluate masseter muscle width and thickness in ultrasonography (USG) and its correlation with dental arch width. Methods In this descriptive-cross-sectional study, 45 participants (25 male (55.5%), and 20 female (45.5%)) were categorized according to their sex and age groups (16–20, 21–25, 26–30 Y.O.). The thickness and anterior-posterior width of the masseter muscle in the rest and clenched states were measured bilaterally using USG with the 7.5 MHz linear probe. Inter-molar width was measured using a metal caliper on dental casts of both jaws. The student t-test analysis was used to compare the means between males and females. The relationship between the width and thickness of masseter muscle and intermolar width was evaluated using Spearman correlation coefficient and Pearson correlation coefficient. Results Males exhibited significantly thicker and wider masseter muscles in rest and clenched states (P < 0.001). They also had wider dental arches in upper and lower jaws (P < 0.001). Intermolar width correlated significantly with muscle dimensions in both states (P < 0.05). However, age and sex categorization revealed no significant correlations between muscle parameters and intermolar widths (P > 0.05). Conclusion USG can be used to measure muscle thickness as a safe and reproducible method. There is a positive correlation between the masseter muscle width and thickness and intermolar width.