Objective: It has been speculated that amoxicillin use could be associated with enamel defects, but there have been few studies of this possible relationship. This study assessed the association between amoxicillin use during the first year of life and primary tooth fluorosis.
Methods: Subjects (n = 490) were recruited at birth and followed prospectively with a series of questionnaires to gather information on fluoride intake and amoxicillin use. Primary tooth fluorosis was assessed by calibrated examiners at approximately 5 years of age.
Results: Amoxicillin use for 6 weeks to 3 months and 3 months to 6 months significantly increased the risk for fluorosis of primary second molars in bivariate analyses. However, after controlling for fluoride intake, the adjusted risks of fluorosis were not significant for amoxicillin use. No other antibiotics were significantly associated with fluorosis in the bivariate analyses. In multivariate analyses with logistic regressions, only fluoride intake was statistically significantly related to fluorosis.
Conclusion: Fluoride exposure was the sole predictor of primary tooth fluorosis in a multivariate model. However, bivariate results suggest that amoxicillin could play a contributing role in the development of primary tooth fluorosis, especially for children exposed to lower levels of fluoride. An investigation of the relationship between amoxicillin intake and fluorosis of permanent teeth is warranted.