# Association of Vertical Facial Patterns With Maxillary Sinus Volume in Skeletal Class I Adults: A Cross-Sectional Cone-Beam Computed Tomographic Study

## TL;DR

This study found that the size of the maxillary sinus is more influenced by vertical maxillary height than by the mandibular plane angle in adults with a skeletal class I pattern.

## Contribution

The study introduces new insights into how vertical facial patterns affect maxillary sinus volume using CBCT scans and semi-automatic segmentation.

## Key findings

- Hyperdivergent individuals had significantly larger maxillary sinus volumes than hypodivergent individuals.
- Maxillary sinus volume showed a stronger correlation with vertical maxillary height than with the mandibular plane angle.
- Normodivergent individuals had intermediate maxillary sinus volumes and vertical maxillary heights.

## Abstract

Introduction

The morphology of the maxillary sinus (MS) is influenced by craniofacial growth patterns, with vertical skeletal discrepancies potentially affecting MS volume. This study aimed to compare MS volume across normodivergent, hyperdivergent, and hypodivergent individuals, and to evaluate the correlation between MS volume, the mandibular plane angle, and vertical maxillary height.

Materials and methods

This retrospective, cross-sectional study included 60 adult patients (age > 18 years) with a skeletal class I pattern and fully erupted permanent dentition. The patients were divided equally into three groups (n = 20 each): normodivergent, hyperdivergent, and hypodivergent, based on the mandibular plane angle. Cone-beam computed tomography (CBCT) scans were obtained and analyzed using ITK-SNAP software for semi-automatic segmentation of MS volume (in mm³) and linear measurements of the anterior and posterior vertical maxillary heights (in mm). The bilateral MS volumes were measured independently by two calibrated examiners to ensure reliability. Statistical analysis was performed using ANOVA, Pearson correlation coefficient, and post-hoc Tukey tests (p < 0.05).

Results

The mean age was comparable across the groups (p > 0.05). No significant differences were found between the right and left MS volumes within groups, indicating bilateral symmetry. However, significant differences in MS volume and vertical maxillary height were observed across the groups (p < 0.05). Hyperdivergent patients exhibited significantly larger MS volumes and greater anterior and posterior vertical maxillary heights than hypodivergent patients. The normodivergent individuals had intermediate values. A moderate positive correlation was found between the mandibular plane angle and posterior vertical maxillary height (p = 0.016), whereas a stronger correlation was found with anterior maxillary height (p = 0.001). The MS volume showed a stronger positive correlation with vertical maxillary height than with the mandibular plane angle.

Conclusion

MS volume was significantly influenced by vertical maxillary height rather than the mandibular plane angle. Hyperdivergent individuals exhibited larger MS volumes and greater vertical maxillary heights compared to hypodivergent and normodivergent individuals. These findings highlight the role of vertical craniofacial dimensions in sinus morphology and may inform clinical decisions regarding orthodontics and maxillofacial surgery.