# Comparison of the Mandibular Buccal Shelf Bone Thickness in Adolescents and Adults Using Cone Beam Computed Tomography

## TL;DR

This study compares the thickness of jawbone in adolescents and adults using 3D imaging to determine the best sites for orthodontic devices.

## Contribution

The study provides new insights into age-related differences in mandibular buccal shelf bone dimensions for orthodontic miniscrew placement.

## Key findings

- Adults have greater vertical bone thickness at deeper levels, especially in inter-radicular regions.
- Horizontal bone thickness in adults is higher at mesial and inter-radicular sites compared to adolescents.
- The region distal to the second molar shows favorable bone dimensions in both age groups.

## Abstract

Introduction

The mandibular buccal shelf is a reliable site for extra-alveolar orthodontic miniscrew placement. The primary stability of temporary anchorage devices depends largely on cortical bone thickness and overall bone morphology. However, age-related variations in buccal shelf bone dimensions have not been fully established, particularly between adolescents and adults with similar growth patterns. The aim of the present study was to evaluate and compare the vertical and horizontal bone thickness of the mandibular buccal shelf in adolescent and adult populations using cone-beam computed tomography (CBCT).

Materials and methods

This retrospective cross-sectional study included 60 CBCT scans divided into two groups: adolescents (12-18 years) and adults (19-35 years), with 30 subjects in each group. Only individuals with average growth patterns and complete permanent dentition were included in the study. Vertical bone thickness was measured at 3, 5, and 7 mm apical to the cemento-enamel junction (CEJ) at three locations: mesial to the first molar, between the first and second molars, and distal to the second molar. Horizontal thickness was assessed at 6 mm and 11 mm apical to the CEJ at the corresponding sites. The measurements were performed bilaterally and averaged. Data were analyzed using mixed-model analysis of variance (ANOVA), with significance set at p<0.05.

Results

Vertical bone thickness increased with depth and showed significant site-related variations. Adults demonstrated significantly greater vertical thickness at deeper levels, particularly in the inter-radicular regions. Horizontal thickness also increased apically, with adults showing greater values at the mesial and inter-radicular sites. The region distal to the second molar consistently exhibited favorable dimensions in both the groups.

Conclusion

The thickness of the mandibular buccal shelf bone varies according to age, depth, and location. Adults demonstrate more favorable bone dimensions for miniscrew stability, particularly in the deeper and inter-radicular regions. CBCT-based individualized assessment is recommended for optimal extra-alveolar anchorage planning.