Evaluation of preventive methods used to interrupt the progression of early caries lesions

The objective was to evaluate the surface hardness of white spot lesions (WSL) treated with different caries prevention methods.

The Knoop microhardness (µKH) of 50 bovine dental enamel fragments was evaluated. WSL were induced (pH cycling) in those fragments and, after µKH analysis, the specimens received the following treatments (n=10): G1- fluoride gel (NaF 2%), G2- fluoride varnish (NaF 5%), G3-brushing with CPP-ACP based dentifrice, G4- infiltrant resin (Icon-DMG) and G5-Er,Cr:YSGG laser (8.92 J/cm2, 0.5 W). A second cariogenic challenge was done after treatments, and surface microhardness was measured before and after treatments. The Knoop hardness (KHN) values obtained were analyzed by one-way ANOVA followed by Tukey´s test (=5%).

After treatments, the KHN was similar to the baseline in all groups. After the second cariogenic challenge, it was observed that G1, G4 and G5 presented KHN similar to their baseline numbers, and in G2 and G3 the KHN was similar to the post-treatment numbers. In general, the recovery of enamel hardness after treatment was above 86%, whith fluoride gel, varnish and Icon achieving slightly better results than the CPP-ACP and Er,Cr:YSGG laser. The analysis of the acid resistance of WSL showed that in groups 1, 3 and 5 the loss of hardness was lower than that observed in G2 and G4.

It was concluded that the treatments recovered the hardness of the demineralized enamel and that, despite the methods tested did not prevent demineralization of WSL, their effectiveness was greater than 85%.