Fractal Analysis of Jaw Bone Structure in Individuals With Dental Fluorosis: A Retrospective Cross‐Sectional Study

OBJECTIVES: This retrospective cross-sectional study aimed to evaluate differences in maxillary and mandibular trabecular bone structure in individuals with dental fluorosis using fractal dimension (FD) analysis. MATERIALS AND METHODS: The study included 47 individuals: 24 with dental fluorosis and 23 controls. Fluorosis severity was assessed using the Thylstrup-Fejerskov Index and classified as moderate (n = 13) or severe (n = 11). FD analysis was performed on standardized regions of interest on digital panoramic and digitized analog periapical radiographs using ImageJ. Normality was assessed using the Shapiro-Wilk test. Region-specific FD values were compared using independent-samples t-tests or Mann-Whitney U tests, as appropriate. Generalized estimating equation (GEE) analyses were used to account for within-participant correlation among repeated regional measurements. RESULTS: In region-specific comparisons, FD was significantly lower in the fluorosis group than in controls in the 33-34 panoramic region (1.46 ± 0.04 vs. 1.48 ± 0.03; p = 0.048). FD was significantly higher in severe than moderate fluorosis in the 13-14 panoramic region (1.36 ± 0.05 vs. 1.28 ± 0.06; p = 0.004) and the 11-12 periapical region (1.63 ± 0.01 vs. 1.61 ± 0.02; p = 0.019). GEE analysis showed a significant average marginal fluorosis-control difference for panoramic radiographs (mean difference = -0.0210, 95% CI: -0.0386 to -0.0034; p = 0.020), without a significant group-by-region interaction (p = 0.840). For fluorosis severity, the severity-by-region interaction was significant for panoramic radiographs (p = 0.004), while average marginal periapical FD was higher in the severe subgroup (p = 0.028). CONCLUSIONS: FD analysis identified differences in radiographic trabecular pattern complexity associated with dental fluorosis, although findings varied by anatomical region and imaging modality. Given the small sample, multiple regional comparisons, and moderate reproducibility of periapical measurements, these findings should be considered exploratory and require confirmation in larger studies using standardized imaging protocols.