AIM: To investigate the risk of sound surfaces, and initial and moderate caries lesions to progress to dentine cavitation in preschool children.

DESIGN: A cohort study was designed with 639 children (12-59 months old) who had been examined by visual inspection during a survey in 2010. After 2 years, 469 children were re-examined regarding the presence of dentine cavitations. The probability of progression was calculated for sound and carious (initial and moderate lesions) surfaces. Relative risk of progression and 95% confidence intervals for each condition compared with sound surfaces were calculated using multilevel Poisson regression analysis. Association with explanatory variables, including caries experience of the children, was also investigated.

RESULTS: The higher the initial score attributed to the dental surface, the more likely was the progression. Moreover, children with severe lesions at baseline had higher risk of having a sound surface or a non-cavitated caries lesion progressing to cavitation when compared with caries-free children; however, this increased risk was not observed in children with only initial caries lesions.

CONCLUSIONS: Initial caries lesions present a low frequency of progression. Moreover, sound surfaces and initial caries lesions in children already presenting cavitations are more likely to progress to more severe conditions.