Analysis of dental amalgam fillings on primary Sjögren's syndrome: A population-based case-control study in Taiwan

Primary Sjören's syndrome (pSS) is an autoimmune disease characterized by the inflammatory infiltrate and progressive dysfunction of salivary glands. Dental amalgam with mercury has been raised the public concerns regarding its purported mercury toxicity from dental amalgam to possible systemic inflammatory and immune reactions. In this study, a nationwide population-based database was employed to investigate the association of amalgam filling (AMF) and the risk of pSS. A retrospective case-control study was sourced from the Taiwanese National Health Insurance Research Database (NHIRD) from 2000 to 2013. Case and control groups were matched by sex, age, urbanization level, monthly income, and comorbidities using the propensity score method with a 1:1 ratio. In this study, 5848 cases and 5848 controls were included. The results demonstrated no statistically significant differences between AMF and pSS (odds ratio [OR]: 0.974, 95% confidence interval [CI] = 0.904–1.049). In addition, pSS was also not associated with AMF for women (OR: 0.743, 95% CI = 0.552–1.000) and men (OR: 1.006, 95% CI = 0.670–1.509), respectively. Taken together, evidence demonstrated that the association of AMF and pSS was inconsistent from this robust register databank.