Evaluation of mandibular bone structures in thyroid dysfunction: a radiomorphometric index and fractal dimension analysis study

Abstract Background Thyroid dysfunctions, particularly hyperthyroidism and hypothyroidism, are endocrinopathies that can affect bone metabolism. This study aimed to evaluate the effects of hyperthyroidism and hypothyroidism on mandibular trabecular and cortical bone structure using fractal analyses (FA) and radiomorphometric indices on panoramic radiographs. Methods This retrospective study was conducted between June 2023 and October 2023 and included patients aged 18 years and older diagnosed with hyperthyroidism or hypothyroidism whose panoramic radiographs were retrieved from hospital archives spanning January 2018 to June 2023. The control group consisted of systemically healthy individuals. In total, 180 panoramic radiographs (60 patients per group) were evaluated. Radiomorphometric indices, including the panoramic mandibular index (PMI), mandibular cortical index (MCI), and mental index (MI) were measured. Three regions of interest (ROIs) were defined in the mandible, and the fractal dimension (FD) was calculated. All measurements were compared among the hyperthyroid, hypothyroid, and control groups. Results A statistically significant difference in the distribution of MCI scores was observed among the study groups ( p < 0.05). PMI and MI values were significantly lower in patients with hyperthyroidism compared to both the hypothyroid and control groups ( p < 0.001). In all ROIs, the hyperthyroidism group exhibited significantly lower FD values compared to the hypothyroidism and control groups ( p < 0.001). Conclusions The findings of this study indicate that individuals with hyperthyroidism showed significantly lower radiomorphometric measurements and FD values compared to hypothyroid and healthy control groups, suggesting cortical thinning and trabecular microarchitectural deterioration. These results suggest that FA and radiomorphometric assessments using panoramic radiographs may serve as adjunctive, non-invasive tools for evaluating mandibular bone structure in patients with thyroid disorders, particularly hyperthyroidism, prior to dental procedures. Validation with biochemical and densitometric data is warranted.