Capacity of a hydroxyapatite–lysozyme combination against Streptococcus mutans for the treatment of dentinal caries

BACKGROUND One current strategy for the treatment of carious lesions is the use of biomaterials with antimicrobial activity. AIMS The aim of this study was to evaluate a combination of hydroxyapatite and lysozyme for the treatment of dentinal caries by measuring Streptococcus mutans counts before carious tissue sealing, and 24 h, 1 month, and 6 months after treatment. MATERIALS AND METHODS Forty permanent third molars were selected, and flat dentin surfaces were prepared. The teeth were exposed to a cariogenic challenge with S. mutans. After challenge, the dentinal caries were collected from five specimens. The remaining specimens were treated with a mixture of hydroxyapatite and lysozyme in sodium laureth sulfate and sealed with composite resin. S. mutans counts were obtained 24 h, 1 month, and 6 months after sealing. STATISTICAL ANALYSIS The results were evaluated by descriptive statistics and Wilcoxon signed-rank test. RESULTS a significant reduction in S. mutans (CFU/mL) was observed in dentinal lesions 1 month after treatment with hydroxyapatite/lysozyme in sodium laureth sulfate (P = 0.0254). Comparison of S. mutans counts obtained 24 h, 1 month, and 6 months after treatment revealed reductions only at the 1-month time point (P = 0.0318). CONCLUSIONS the combination of hydroxyapatite and lysozyme may be an alternative for reducing the S. mutans burden in dentinal caries.