Supplementary Material for: The association between lead exposure and dental caries ─ a systematic review

Introduction: Dental caries has declined over the years, but it remains a major public health issue. This review aimed to investigate the association between lead and caries experience in either deciduous or permanent teeth.

Methods: A comprehensive search of PubMed, EMBASE, and Google Scholar was conducted to identify relevant studies published up until December 2022. Included were human observational studies that investigated the association between lead exposure and dental caries. The review adhered to the PRISMA guideline.

Results: Sixteen studies were included in this review, with nine focusing on deciduous teeth, thirteen on permanent teeth, and six examining both types of teeth. Most of the studies (5 of 6) found a positive association between blood lead (PbB) levels and caries in deciduous teeth, while the findings for permanent teeth were less conclusive, with only 3 of 10 studies finding an association. One of the two studies assessing salivary lead (PbSa) levels found a weak association for permanent teeth. All four studies that examined lead (Pb) concentration in teeth found a positive association for both deciduous and permanent teeth.

Conclusion: Many published studies indicated a positive association between Pb exposure and caries experience in deciduous dentition. Children with elevated PbB level should be considered as having higher caries experience. Due to lack of consensus on measurement and examination technique, there remains insufficient evidence to make any definitive conclusions especially in permanent teeth, and so more studies are warranted.