Method: One hundred and twenty, 36-71 months-age low-income children, from the city of Fortaleza (Brazil), at high risk for developing ECC were selected to participate in this study. Children were randomly assigned to receive varnishes containing one of four treatments: 20%CAR, 10%CAR/THY, 20%CHX or 5%NaF. Dental examination was performed by one previously calibrated examiner (Kappa=0.83) to evaluate the number of decayed, missing and filled tooth surfaces (dmfs). Antimicrobial applications and examinations occurred at 3 months intervals during 1 year. Exams were performed at the first appointment (E1) and within 3, 6 and 12 months (E2, E3, E4). P-value≤0.02 was considered statistically significant.
Result: A difference (p=0.001) was observed in caries experience between exams, except between E1 (dmfs=0) and E2 (dmfs=0.06; p=0.024), and between E3 (dmfs=0.28) and E4 (dmfs=0.38; p=0.184). Comparisons between examinations within groups showed a significant differences for all treatments (CAR,p=0.02; CAR/THY,p=0.001; CHX,p=0.005; NaF,p=0.009). Statistical difference was found between E1 and E3 for all treatments (CAR,p=0.011; CAR/THY,p=0.005; CHX,p=0.019), except for NaF (p=0.042). At the 1-year follow-up, children treated with NaF varnish had dmfs value of 0.28, followed by CAR group (dmfs=0.36), CAR/THY group (dmfs=0.43) and CHX varnish (dmfs=0.48). Caries increments did not differ between groups (E2-E1: p=0.402; E3-E2: p=0.586; E4-E3: p=0,971) or intra group (CAR,p=0.417; CAR/THY,p=0.032; CHX,p=0.282; NaF,p=0.117).
Conclusion: Our results demonstrated that none of the tested substances prevented the appearance of new carious lesions in this high-risk, initially caries-free population. However, all tested varnishes controlled the appearance of new lesions, as demonstrated by the low caries experience of all children, with no difference in anti-caries efficacy between groups.