Association between enamel hypoplasia and dental caries in primary second molars and permanent first molars: A 3-year follow-up study

Context: Enamel hypoplasia is a defect caused by disturbances during enamel formation. These defects in the enamel present important clinical significance as they predispose a tooth to dental caries. Aim: The aim of this study was to assess the longitudinal relationships between enamel hypoplasia and caries experience of primary second molars and permanent first molars. Materials and Methods: The study sample consisted of 765 subjects who underwent dental examinations at both ages 6 and 9 by the calibrated examiner. Primary second molars and permanent first molars were scored for the presence of enamel hypoplasia for each participant. Caries presence and number of decayed and filled surfaces (dfs and DFS) were determined at ages 6 and 9. The relationships between enamel hypoplasia and caries experience were assessed using multivariable regression models. Results: At the tooth level, 2.8% and 3.5% of children had hypoplasia on primary second molars and permanent first molars respectively. Multivariable logistic regression analyses showed that children with enamel hypoplasia were at a significantly higher risk of caries at both ages 6 (odds ratio, OR = 5.27 for primary second molars and OR = 3.21 for permanent first molars) and age 9 (OR = 3.45 for primary second molars and OR = 4.57 for permanent first molars), and that a statistically significant association was seen with caries incidence (OR = 2.08 for primary second molars and OR = 2.87 for permanent first molars). Conclusion: Enamel hypoplasia appears to be a significant risk factor for caries in both primary second molars and permanent first molars and should be considered in caries risk assessment.