AbstractObjectivesEpidemiological studies on developmental defects of enamel (DDE) have focused on its potential contributory factors and prevalence while there is limited evidence on the longitudinal changes in the epidemiological profile of DDE. Thus, the objective of this longitudinal study was to investigate whether any type of DDE changes with time.MethodsA total of 668 participants were initially recruited in 2010, and 432 participants were successfully followed up and examined for DDE both at the age of 12 in 2010 and 15 in 2013. The central incisor, lateral incisor and first molar in each quadrant were chosen as index teeth and were examined ‘wet’ by two trained and calibrated examiners using the modified FDI (DDE) Index.ResultsThe mouth prevalence and tooth prevalence of ‘any defect’ showed a significant decrease from 2010 to 2013 (P < 0.001). This was predominantly due to the decrease in diffuse opacities (P < 0.001). Significant difference in the distribution of the extent of DDE was also found for diffuse opacities at both the participant and tooth levels irrespective of the types of tooth (P < 0.0001). Median extent score for diffuse opacities in 2013 was lower than those in 2010 at both participant and tooth level irrespective of the types of tooth (P < 0.001).ConclusionsDiffuse opacities, in terms of prevalence and severity, did fade out over time. The observed overall change in DDE was due to the dominating effect of diffuse opacities over demarcated opacities and hypoplasia.