The risk of
dental caries seems to be greater in the presence of
developmental defects of enamel (
DDE). The aim was to determine whether the presence of
DDE in the primary teeth of preschool children increases the risk of
dental caries in the primary dentition after a period of approximately 2 years. This study was conducted in two stages: baseline (T0) and follow-up (T1). At T0, examinations were conducted for the diagnosis of enamel defects using the
DDE index (FDI, 1992),
dental caries, and
oral hygiene. The participants were allocated to two groups according to the presence (affected) or absence (unaffected) of
DDE. At the second evaluation (T1), examinations were performed for the diagnosis of
dental caries. Poisson regression analysis with a multilevel approach was used to determine the association between
DDE and
dental caries. The two levels of the analysis were tooth and child. Among the 339 children (113 affected and 226 unaffected) examined at baseline (T0), 325 were re-examined at follow-up (T1). According to the multilevel analysis, teeth with
enamel hypoplasia had a greater risk of having
dental caries (RR: 1.99; 95% CI: 1.19-3.33). The risk of caries was greater on posterior teeth (RR: 2.59; 95% CI: 2.18-3.07) and maxillary teeth (RR: 1.48; 95% CI: 1.26-1.75) that had
DDE at T0. On the child level,
dental caries at T1 was associated with having
dental caries at T0 (RR: 1.38; 95% CI: 1.32-1.46). In conclusion,
enamel hypoplasia and previous
dental caries are risk factors for
carious lesions in the primary dentition.