Effects of various agents and laser systems on antibacterial activity and microtensile bond strength when used for cavity disinfection Ipek Arslan, Ozgul Baygin, Gulcin Bayram, Rukiye Akyol, Tamer Tuzuner Journal of Dental Lasers 2019 13(1):12-18 Context: Cavity disinfection is recommended with the routine caries removal methods in order to eliminate the microorganisms and to reduce potential secondary caries. Aims: The aims of this study were to evaluate the antibacterial effects of Corsodyl; Cervitec; Cervitec Plus; Fluor Protector agents and FotoSan; diode laser; and erbium, chromium: yttrium, scandium, gallium, garnet (Er, Cr:YSGG) laser systems on Streptococcus mutans and Lactobacillus acidophilus as well as their effects on the microtensile bond strength. Materials and Methods: A cavity tooth model test was used to determine antibacterial activity after which the effects of the same agents and systems on the microtensile bond strength were evaluated. Eight cylindrical cavities were prepared on the dentin surface of 24 bovine incisors, and 12 of them were left in contact with S. mutans; others were left in contact with L. acidophilus. Test agents and systems were applied, and standardized amounts of dentin chips were obtained from the cavity walls. The number of bacteria recovered was counted. The effect of tested agents and systems on bond strength was evaluated with microtensile bond strength test. Statistical Analysis Used: Statistical analysis was carried out using the Kruskal–Wallis and Mann–Whitney U tests for the cavity tooth model test, and one-way ANOVA and Tukey test for microtensile bond strength test. Results: Test results showed that all of the disinfection methods demonstrated significant antibacterial activity on both S. mutans and L. acidophilus (P < 0.01). The agents used in this study significantly reduced the microtensile bond strength (P < 0.05) whereas the Er, Cr:YSGG laser significantly increased the bond strength (P < 0.01). Conclusions: Er, Cr:YSGG laser can be recommended for cavity disinfection due to its superior antibacterial activity and increased bond strength.