Dental amalgam fillings and Sjögren's syndrome

Dental amalgam fillings and Sjögren's syndrome study results

This is a summary of a population-based case-control study in 
Taiwan to investigate the association of amalgam filling and the risk of Sjögren's syndrome.

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. 

The research scientists analyzed data from people newly diagnosed with primary Sjögren’s syndrome with no other health conditions and a control group of people without the disease.

They were testing the idea that more primary Sjögren’s patients than controls had been exposed to amalgam fillings, as such a finding would suggest that these fillings can increase the risk of getting Sjögren’s.

The results of the study showed no difference in amalgam filling exposure between the two groups.

1 Introduction

It has been a long time that dental amalgam has been used for caries restoration. Dental amalgam is composed of silver alloys and mercury. Previous studies have reported that mercury vapor could be released for dental amalgam. 

Little is known about the impact of amalgam filling (AMF) on pSS, therefore, the authors analyzed the risk of AMF for pSS from the National Health Insurance Research Database (NHIRD) by case-control design in the Taiwanese population.

2 Methods

2.1 Data source

The Longitudinal Health Insurance Database (LHID) 2010 was used for this case-control study. This research database includes the details of all medical services utilized by the enrollees. The codes of disease diagnoses and treatment procedures are based on the International Classification of Diseases, ninth revision, Clinical Modification (ICD-9-CM). Under surveillance by the Bureau of National Health Insurance (NHI), the validation of LHID 2010 data is associated with public confidence. Many studies have been published from NHIRD that represented the epidemiological profiles of the Taiwanese population. This study was approved by the institutional review board of Chung Shan Medical University Hospital.

2.2 Study design

They excluded patients with autoimmune diseases such as systemic lupus erythematosus,  dermatomyositis, polymyositis, rheumatoid arthritis, and ankylosing spondylitis to ensure the validity of the pSS diagnoses. 

The comparison subjects were selected from the random sample of the general population. selected comparison subjects from the general population matched by sex, age, urbanization level, socioeconomic status, and comorbidities using the propensity score method at a 1:1 ratio for each case.

3 Results

No statistically significant difference between AMF and pSS was observed. In addition, pSS was not associated with AMF regardless of gender,

4 Discussion

To the best of our knowledge, this case-control study is the first to use nationwide, population-based longitudinal administrative data to examine the association between AMF and pSS. The findings show that people with AMF were not at a higher risk of pSS in Taiwanese population.

Dysfunction of salivary glands is the main symptom in pSS patients. Studies have shown that pSS patients face a high risk of developing dental caries due to xerostomia. Recently, Chuang et al reported that the risk of dental caries was significantly higher in patients with pSS from Taiwanese NHIRD. Taken together, it could be explained that SS is associated with a high risk of caries, therefore, amalgam is a material of choice for people with high susceptibility to dental caries.

5 Conclusions

This population-based case-control study preliminarily proposed that AMF was not associated with pSS. However, approximately 50% of dental amalgam is elemental mercury by weight, it is still a public concern for continuing use of dental amalgam or not. Thus, the cause-effect relationship and pathophysiology are still necessary to further investigations.

Analysis of dental amalgam fillings on primary Sjögren's syndrome
A population-based case-control study in Taiwan
Chen, Kun-Huang PhD Yu, Hui-Chieh DDS, PhD Chang, Yu-Chao DDS, PhD
Editor(s): Saranathan., Maya
Medicine: November 24, 2021 - Volume 100 - Issue 47 - p e28031
doi: 10.1097/MD.0000000000028031

A study into Dental amalgam fillings and Sjögren's syndrome