# Fractal dimension and cortical indices of the mandible in hypercholesterolaemia: a retrospective study

## TL;DR

This study explores how high cholesterol might affect the bone structure of the jaw, using dental X-rays to detect subtle changes that could influence implant treatments.

## Contribution

The study introduces fractal analysis of panoramic radiographs as a potential non-invasive method to detect bone microarchitecture changes in hypercholesterolaemia.

## Key findings

- Elevated cholesterol levels may be linked to subtle changes in anterior mandibular trabecular bone microarchitecture.
- Fractal dimension showed borderline significance between high and normal cholesterol groups.
- No significant differences were found in lacunarity, cortical width, or panoramic mandibular index across groups.

## Abstract

Hypercholesterolaemia has been associated with changes in bone metabolism, but its potential impact on mandibular bone microarchitecture, as observed in dental panoramic radiographs, remains unclear. Understanding these relationships may improve pre-implant assessment and treatment planning. This study aimed to investigate whether fractal dimension, lacunarity, mandibular cortical width, and the panoramic mandibular index differ among patients with varying serum total cholesterol levels.

This retrospective study analysed panoramic radiographs from adult patients referred for dental implant treatment. Participants were stratified into three groups based on total cholesterol level: normal (< 5.2 mmol/L), borderline high (5.2–6.2 mmol/L), and high (> 6.2 mmol/L). Standardised 64 × 64 pixel regions of interest were selected in anterior, premolar, and molar mandibular regions. Fractal dimension and lacunarity were calculated using a box-counting approach, while mandibular cortical width and the panoramic mandibular index were measured manually at the mental foramen. Group comparisons were performed using the Kruskal-Wallis test with Bonferroni-corrected post-hoc analysis.

A total of 92 patients were included (35 normal, 33 borderline, 24 high cholesterol). Although the Kruskal-Wallis test indicated a difference in fractal dimension among cholesterol groups (p = 0.047), the post-hoc analysis revealed only a borderline significance between the high and normal groups (adjusted p = 0.050). Therefore, this finding should be interpreted cautiously. No significant differences were observed in the premolar or molar regions, or in lacunarity, mandibular cortical width, or panoramic mandibular index.

Findings suggest that elevated cholesterol levels may be associated with subtle alterations in trabecular bone microarchitecture in the anterior mandible. Fractal analysis of panoramic radiographs could provide a non-invasive adjunct for early detection of bone changes in patients with lipid imbalance, potentially supporting individualised implant treatment planning. However, these observations should be interpreted with caution, and further studies are needed to confirm the reproducibility and clinical relevance of these findings.

Not applicable.

The online version contains supplementary material available at 10.1186/s12903-026-07817-6.