13-Year Cohort Study on Inactive Occlusal Enamel Caries Lesions

This cohort study evaluated the clinical behavior of dental caries lesions classified as inactive on the occlusal surfaces of permanent molars, defining their risk for progression after 13 years, in comparison with sound occlusal surfaces.

Clinical assessments were undertaken at baseline (n = 258), after 1 year (n = 200), 4-5 years (n = 193), and 13 years (n = 102). Plaque and dental caries were recorded on the occlusal surfaces, as well as the eruption stage of permanent molars. Outcomes were progression by activity (active lesion, filling or extraction in the follow-up exam) and progression by severity (dentin cavity, filling or extraction in the follow-up exam). Predictors were occlusal site status, plaque accumulation on occlusal surfaces, eruption stage, type of molar, and dental arch, all of them collected at baseline. Logistic regression models were fitted using generalized estimating equations due to data clustering.

A total of 601 occlusal surfaces were reexamined. For the activity criterion, progression rates were 8.7% for sound sites and 18.8% for caries lesions initially classified as inactive (p < 0.05). For the severity criterion, the respective rates were 5.8% and 13.4% (p < 0.001). Inactive occlusal caries lesions had about twice the risk for caries progression than sound surfaces, for both the activity criterion (adjusted OR = 2.09, 95% CI = 1.23-3.52) and the severity criterion (adjusted OR = 2.49, 95% CI = 1.42-4.35).

The vast majority (>80%) of lesions initially classified as inactive did not progress after 13 years. However, they showed higher risk for progression than sound occlusal surfaces of the same patients.