# Symphyseal Morphology in Sagittal Skeletal Discrepancies: A Retrospective Observational Study

## TL;DR

This study found that jaw misalignment (skeletal class) is linked to changes in the shape of the lower jaw's midline, with specific patterns observed in different jaw types.

## Contribution

The study identifies a weak negative correlation between ANB angle and symphysis height, and a moderate positive correlation between ANB and IMPA.

## Key findings

- A weak negative correlation was found between ANB angle and symphysis height (r = −0.25, p < 0.01).
- Class III subjects had significantly greater symphyseal height than Class II subjects (p < 0.001).
- Class II subjects showed the highest IMPA values (p < 0.001).

## Abstract

Background: The aim of this study was to evaluate the correlation between skeletal class and morphological patterns of the mandibular symphysis. Methods: The sample consisted of 90 patients with an average age of 18 years (44 > x > 12). In order to investigate any correlation between skeletal class and morphological patterns of the mandibular symphysis, the following tests were used: Pearson’s correlation test, Spearman’s test, and the analysis of variance test (ANOVA) followed by Tukey’s post hoc HDS test. The significance level was set at 0.050. Results: Pearson’s correlation test and ANOVA showed a weak negative correlation between malocclusion and symphyseal height. Therefore, as ANB increases, symphyseal height decreases (r = −0.25, p < 0.01). In addition, a strong positive correlation was found between ANB and IMPA (r = 0.47, p < 0.01). So, as ANB increases, IMPA increases. No statistically significant association was found between symphyseal morphology and IMPA (Spearman’s test). Conclusions: The analysis revealed a weak but statistically significant negative correlation between ANB angle and symphysis height, indicating that as sagittal discrepancy increases (higher ANB), the symphysis tends to be shorter (r = −0.25, p < 0.01). A moderate positive correlation was also found between ANB and IMPA (r = 0.47, p < 0.01), suggesting that a more pronounced Class II skeletal pattern is associated with greater incisor proclination. However, no significant relationship was observed between symphysis type (A/B/C) and IMPA. When comparing skeletal classes, Class III subjects displayed significantly greater symphyseal height than Class II subjects (p < 0.001), while Class II subjects showed the highest IMPA values (p < 0.001).