Incorporation of chlorhexidine diacetate in provisional cements: Antimicrobial activity against Streptococcus mutans and the effect on tensile strength in vitro

Aim To test the antibacterial capacities and tensile strengths of three commercially available provisional cements to which chlorhexidine diacetate was added and compare them to the same unmodified cements. Methodology Sixty cylindrical samples were prepared from either three noneugenol provisional cements or the same cements modified by the addition of chlorhexidine diacetate at 7.5% w/w, with a total of 360 samples. The cements tested included Tempbond NE, Rely X Temp NE and Freegenol. Forty-eight samples from each cement were aged in saline that was replaced twice a week for up to 96days. Twelve of these samples were removed at either 1, 15, 30 or 96days and assessed for antibacterial properties against Streptococcus mutans with an agar diffusion test. Twelve samples of each cement, with and without chlorhexidine diacetate, were also tested 7days after the initial setting for their tensile strength using a diametrical tensile strength test applied with an Instron machine. The results were analysed using either one-way or three-way anova. Results The addition of chlorhexidine diacetate resulted in provisional cements with antibacterial properties that persisted through ageing in saline for up to 96days. The addition of chlorhexidine did not reduce the diametrical strength of the cements. Conclusions The addition of chlorhexidine diacetate to provisional cements rendered all three cements antibacterial against S. mutans and this activity was maintained even after prolonged ageing of the cements, without compromising their tensile strength at 7days.