# Mandibular Cortical Thickness Predicts Skull BMD in Adolescents

## TL;DR

Thicker mandibular cortex in adolescents is linked to higher skull bone mineral density, suggesting dental X-rays could help identify children with low bone density.

## Contribution

This study is the first to show that mandibular cortical thickness from dental X-rays is a reliable predictor of skull BMD in children.

## Key findings

- Mandibular cortical thickness measures (MI and sPMI) are significantly associated with skull BMD in peripubertal children.
- The association remains significant even after adjusting for confounders and using a Mendelian randomization framework.
- Children with extreme genetic predispositions for BMD showed measurable differences in mandibular cortical thickness.

## Abstract

Bone mass accrual during childhood and early adulthood is the most important modifiable determinant of lifelong skeletal health. Dental panoramic radiographs (DPRs) and measurements derived from them have yet to be assessed as a screening tool for low bone mineral density in children. Skull bone mineral density (SK-BMD) has high heritability and is less affected by environmental factors than measures of BMD at other skeletal sites. This study aimed to analyze the relationship between mandibular cortical thickness and SK-BMD in peripubertal children. This population-based cross-sectional study involved 2672 children aged 13 years from the Generation R Study. Mandibular cortical thickness was obtained from DPRs and quantified with the mental index (MI) and the superior panoramic mandibular index (sPMI). SK-BMD was quantified from total body dual-energy X-ray absorptiometry scans and weighted polygenic scores (wPGS). The determinants of mandibular cortical thickness were also assessed. The analysis was done with linear regression models, adjusted for confounders, and within a Mendelian randomization (MR) framework. Both MI and sPMI were significantly associated with SK-BMD in fully adjusted models. When the characteristics of the participants stratified for the extreme quintiles of the SK-BMD wPGS distribution were compared, only SK-BMD (p value < 0.001), sPMI (p value = 0.032), and MI (p value < 0.001) differed significantly between extremes. Mandibular cortical thickness parameters were significantly associated with SK-BMD in an unconfounded setting. DPRs may serve as a valuable tool for surmising low BMD in peripubertal children, once clinical cutoffs for mandibular cortical thickness are established.

The online version contains supplementary material available at 10.1007/s00223-026-01501-1.