Prevalence of thyroid cancer linked to maxillofacial radiology exposure: A retrospective study from western Iran

Background: Thyroid cancer incidence has been increasing worldwide, and ionizing radiation is a well-established risk factor. Dento-maxillofacial radiology is widely used in clinical practice, often resulting in repeated exposure to radiation. This study aimed to evaluate the association between the frequency of Dento-maxillofacial radiology exposures and the risk of thyroid cancer in patients from western Iran. Methods: A case–control study was conducted, including 460 patients with thyroid cancer and 460 healthy controls. Exposure history was categorized into three groups: ≤5, 6–10, and >10 exposures. Conditional logistic regression was used to estimate odds ratios (ORs) with 95% confidence intervals (CIs), adjusting for age, gender, nationality, histological types, and history of exposure to diagnostic Dento-maxillofacial  radiology (including the number of exposures). Results: Among thyroid cancer patients, 14.6% had ≤5 exposures, 37.4% had 6–10 exposures, and 48.0% had >10 exposures, compared with 32.6%, 37.0%, and 30.4% among controls, respectively. Crude analysis showed increasing odds of thyroid cancer with higher exposure (OR = 2.26; 95% CI: 1.58–3.23 for 6–10 exposures; OR = 3.54; 95% CI: 2.48–5.06 for >10 exposures). After adjustment, the association remained significant (OR = 2.00; 95% CI: 1.35–2.95 for 6–10 exposures; OR = 3.00; 95% CI: 2.05–4.40 for >10 exposures). A dose–response relationship was evident (P < 0.001). Conclusion: Repeated Dento-maxillofacial radiology exposures are associated with a significantly increased risk of thyroid cancer in a dose-dependent manner, independent of demographic factors. These findings highlight the importance of minimizing unnecessary radiographs and reinforcing radiation protection protocols in dental and maxillofacial practice.