Effect of Light Curing on Silver Diamine Fluoride in Primary Incisors: A Microscopic Ex Vivo Study

Purpose: To determine the effect of a dental curing light on the penetration depth of silver diamine fluoride (SDF), dentin hardness, and silver and fluoride ion precipitation into cavitated carious lesions. Methods: SDF was applied on 16 primary incisors extracted due to caries extending into dentin. Teeth were divided into two groups: (1) control group, was not light-cured; and (2) test group, was light-cured. A scanning electron microscope, and OmniMet software were used to measure penetration depth, dentin hardness, and ion precipitation. Wilcoxon's ranksum test was used for statistical analysis. Results: All samples in both groups showed SDF penetration beyond the carious lesion and into sound dentin. The penetration depth into sound dentin was 70 μm further without the dental curing light it (P<0.001). Silver precipitation in infected dentin with the dental curing light was approximately 2.6 times greater than without it (P=0.02). Dentin hardness of infected dentin was 26 percent more with the dental curing light (P=0.04). Conclusions: Applying a dental curing light during silver diamine fluoride treatment of carious lesions induces more silver ion precipitation in infected dentin, increases its hardness, and, perhaps because more silver stays in the infected dentin, less SDF penetrates into sound dentin.