Antibacterial activity and tensile strength of provisional cements modified with fluoridecontaining varnish

Objective: To test three noneugenol provisional cements (TempBond NE, RelyX Temp NE, and Freegenol) for their antibacterial properties and to test the hypothesis that addition of fluoride varnish confers antibacterial properties on these provisional cements without compromising their tensile strength. Method and Materials: A total of 576 cylindrical samples were prepared (96 of each of six types) from three noneugenol provisional cements, both unmodified and modified by the addition of 5% w/w Duraphat fluoride varnish. The samples were aged in saline that was replaced twice a week for up to 90 days. Twenty-four samples of each type were removed from the saline at 1, 7, 30, or 90 days and assessed for antibacterial properties against Streptococcus mutans by using an agar diffusion test (n = 12) and tensile strength by using a diametral tensile strength test (n = 12). Data were subjected to one- and three-way ANOVA, the Tukey honestly significant difference test, and t test at a significance level of .002 (P .002). Results: TempBond NE had no antibacterial activity in its unmodified form but showed antibacterial activity when modified by the addition of 5% w/w fluoride varnish. Freegenol had the highest antibacterial activity in its unmodified form, which was not altered by the addition of the varnish. RelyX Temp NE had mild antibacterial activity that was slightly enhanced by adding the varnish. Adding the varnish reduced the tensile strength of TempBond NE and Freegenol, but did not affect the tensile strength of RelyX Temp NE. Conclusion: Antibacterial activity was observed for the unmodified form of Freegenol and TempBond NE after the addition of the fluoride varnish. The addition of the fluoride varnish reduced the tensile strength of both TempBond NE and Freegenol. Palabras clave: antibacterial, cement, diametral tensile strength, fluoride varnish, provisional cement, Streptococcus mutans, zinc oxide-eugenol