Tetracycline-induced tooth changes. Part 5. Incidence in extracted first permanent molar teeth: a resurvey after four years.

First permanent molar teeth extracted during 1972 from patients aged 6 to 18 years attending the Royal Dental Hospital of Melbourne were sectioned sagittally and examined under ultraviolet light for fluorescent tetracycline deposits. The prevalence of fluorescent teeth increased with decreasing age to 84% in patients aged 10 to 11 years, then decreased in the younger children until only 67% were affected at six to seven years of age. Detailed analysis of the distribution of antibiotic in teeth demonstrated a marked decline in tetracycline experience since 1962-1964, i.e., fewer children received courses of the antibiotic, and confirms the trend demonstrated in a similar survey four years age. This trend is associated with a lower incidence and severity of crown discoloration and accompanying enamel hypoplasia in the youngest children examined.