A Longitudinal Observational Study of Developmental Defects of Enamel from Birth to 6 Years of Age.

Developmental defects of the enamel (DDE) commonly occur in the primary dentition. Although several cross-sectional studies have shown the association of DDE with caries, there is a paucity of longitudinal studies demonstrating that teeth with DDE are at greater risk of caries than are normal teeth. Therefore, the aim of the present study was to longitudinally track a total of 14,220 primary teeth in 725 children from a large birth cohort study, who were interviewed by telephone or home visits at 6-mo intervals. There were 74 children with at least 1 tooth with DDE. We compared teeth with and without DDE by calculating hazard ratios for caries using a Cox proportional hazards model and by plotting caries-free probabilities by child's age for DDE categories in a Kaplan-Meier plot. Our results show that teeth with DDE had a much higher risk for caries and developed caries earlier than did teeth without DDE. The hazard ratios (95% confidence intervals) for caries were 6.0 (2.4 to 14.6; P < 0.001) for pits, 5.5 (3.8 to 7.8; P < 0.001) for missing enamel, and 4.5 (1.8 to 11.3; P < 0.002) for hypoplasia occurring with yellow-brown opacities. Kaplan-Meier survival plots of caries-free probabilities by age, depending on DDE type, suggest that all types of enamel hypoplasia are associated with a statistically significant increased risk for caries. The study provides longitudinal evidence that DDE are a strong determinant for caries in the primary dentition (ACTRN No. 012606000356561). Knowledge Transfer Statement: The study provides longitudinal evidence that developmental defects of enamel of the primary dentition are strongly associated with increased risk of early childhood caries.