The frequent use of the antibiotic amoxicillin in infancy may be associated with damage to permanent teeth. Amoxicillin usually is prescribed to treat ear infections. The study, which tracked 579 children from birth to age 10, found that regular use of the antibiotic seemed related to fluorosis, a disorder that damages tooth enamel.

The results of the study indicated that 75% of the participants had been treated with amoxicillin by the age of 12 months and 92% by 32 months. The participants were examined for fluorosis at ages 8 to 10, after earlyerupting permanent teeth had come in. The researchers concluded, after adjusting for other variables, that using amoxicillin mainly in the first 6 months was closely associated with fluorosis. (The findings were reported recently in the Archives of Pediatric and Adolescent Medicine.)