This longitudinal study investigated the sequelae of enamel defects in a group of 25 white, very-low birthweight (VLBW), preterm children (mean birthweight 969 +/- 218 g, mean gestational age 27 +/- 1.9 weeks). Twenty-five race-, age-, and sex-matched, full-term normal birthweight (NBW) control children born at the same hospital, were selected randomly from hospital records. The children were examined at approximate ages of 30, 44, and 52 months. At all examinations, VLBW children had significantly higher prevalence of enamel hypoplasia than did the NBW children. At the last recall examination, 96% of VLBW group, and 45% of the NBW group had at least one tooth with enamel defect, with a mean of 7.6 +/- 4.9 affected teeth per VLBW child, and only 1.0 +/- 1.3 affected teeth per control child (P < 0.001). A significant association of enamel defects with dental caries was observed only in the VLBW group on the second and third examinations (P < 0.001). The defect identified to be most significantly associated with dental caries was a variant showing both enamel hypoplasia and opacity. In spite of a high prevalence of enamel defects, the overall prevalence of dental caries in the VLBW children was not significantly different from that of NBW controls at all three examinations (P < 0.1). Other caries risk factors such as levels of Streptococcus mutans infection, fluoride supplementation, plaque scores, toothbrushing frequency, and daily sugar exposures were examined but none was found to be related significantly to development of dental caries.