Effect of 6-monthly applications of chlorhexidine varnish on incidence of occlusal caries in permanent molars: a 3-year study

Objectives: The aim of this study was to assess the effect of a chlorhexidine varnish on occlusal caries incidence when applied 6-monthly into the fissures of erupting and freshly erupted permanent molars. Methods: In a double-blind clinical trial, 332 children aged 5/6 and 11/12 years attending a Child Dental Health Centre were randomly assigned to a control and an experimental group. Criteria for inclusion in the study were that all first permanent molars in 5–6-year-olds and all second permanent molars in 11–12-year-olds either had recently erupted, or were in a stage of eruption, or would erupt within half a year. At baseline, counts of dmfs/DMFS and mutans streptococci in saliva were recorded. During a maximum of 3 years, every 6 months the occlusal surfaces of molars in the experimental group received a 40% chlorhexidine varnish application, whereas those in the control group received a placebo varnish application. Results: Data of 316 children were analysed and ANOVA showed no significant occlusal caries reduction in this sample of Dutch 5/6- and 11/12-year-old children. After stratification into low and high caries risk groups, a statistically significant caries-reducing effect on occlusal caries in permanent molars was found in the group of children with ≥106 mutans streptococci per ml saliva (P<0.05). Conclusion: Six-monthly application of chlorhexidine varnish has no caries-reducing effect on occlusal caries in recently erupted permanent molars in a population with low caries prevalence.