Effect of luting cement on dental biofilm composition and secondary caries around metallic restorations in situ.

Since the importance of luting cement on secondary caries in enamel and dentin is unknown, an in situ crossover study was conducted in three phases over 21 days using a fluoride-containing toothpaste. One hundred and twenty-six metallic restorations were cemented into the dentinoenamel junction of slabs of human teeth with zinc phosphate (ZP), resin-modified glass ionomer (GI) or resinous cement (RC). The slabs were inserted onto flanges of the removable partial acrylic dentures of 14 volunteers and covered with gauze to enhance dental plaque accumulation. The volunteers used fluoride toothpaste (1.100 microg F/g, w/w). After 21 days, the biofilm that formed on the slabs was collected for biochemical and microbiological analyses, and the demineralization in enamel-dentin around the restorations was evaluated. The fluoride concentration of biofilm in the GI group was higher (p<0.05) than the ZP and RC groups. Also, the concentration of Zinc in biofilm formed on the slabs cemented with ZP was higher (p<0.05) than the other groups. However, the effect of the luting material on enamel or dentin demineralization was not statistically significant (p>0.05). The data suggest that when fluoride toothpaste is used, the anticariogenic property of the luting cement may not be relevant to the reduction of secondary caries.