Topcuoglu, Ozan, Ozyurt, Kulekci cording to the optical density measurement of the propolis is considered to be safe in low doses. The formatted bioﬁlm, the number of viable bacteria cytotoxicity tests have showed that the propolis was lower in the GIC containing 50% EEP than the solutions, even the propolis used in our study, are 25% and the conventional GIC (P<.001) (Table 3). safe for gingival ﬁbroblasts.32 The chemical com- As can be seen in Table 3, the mean bacteria count position of propolis is complex and highly variable in the bioﬁlm on the 25% EEP added GIC was lower depending on its geographical origin. There are than the conventional GIC but the difference was several studies on antibacterial activity of Turkish not statistically signiﬁcant. propolis.33-36 The antimicrobial assays in this study demonstrated that the propolis collected from DISCUSSION Trabzon/ Turkey has signiﬁcant activity against S. GICs are capable of releasing ﬂuoride, which mutans growth, showing a MIC value of 25 µg/mL. contributes to some reduction in the number of re- EEP should be kept as low as possible, as the EEP sidual bacteria in cavities6,7,17 as well as reminer- does not contribute to the formation of the glass alization of softened dentin.22-25 Several attempts ionomer network, and therefore, high amounts of in developing GICs with antibacterial effects by EEP would weaken the scaffold and compromise the addition of antibacterial solutions such as the physical properties of the antibacterial glass chlorhexidine (CHX) have been reported.25-30 With ionomer. According to disk diffusion test, we found regard to these studies, we decided to use EEP, that sizes of inhibition zones produced against S. which showed remarkable antimicrobial activities mutans were not dependent upon the concentra- against several oral microorganisms such as mu- tion of EEP, which means that antibacterial activi- tans streptococci in recent studies.7,8,11,31 ties were not effectively enhanced by increasing Previous studies using conventional GICs dem- concentrations of the agent. So it would be more onstrated conﬂicting results about antibacterial appropriate to use 25% EEP addition for develop- effects observed by the addition of CHX. Some of ment in antibacterial GICs. the studies reported that antimicrobial activity was Bacterial adherence to tooth and restoration dependent upon the concentration of disinfectant surface is a very important stage in the pathogen- added to GICs, 25,27,30 and others indicated no dose- esis of dental caries and soft tissue inﬂammations. response effects.26 Beside its antimicrobial activity, The adherence mechanism of bacteria to the tooth Table 1. The inhibition zone diameters of the GIC disks (mm). GIC type n Mean Standard Deviation Median ***Statistically signiﬁcant (P<.001) GIC type n Mean Standard Deviation Median ***Statistically signiﬁcant (P<.001) Table 2. The dry bioﬁlm weights of the GIC disks (mg). Table 3. The optical densities of the bioﬁlms (OD640). GIC type n Mean Standard Deviation Median ***Statistically signiﬁcant (P<.001) October 2012 - Vol.6 Control 7 0,3 0,1 0,3 Control 13 0,5846 0,3262 0,5 Control 13 0,028 0,016 0,026 25% EEP 7 0,7 0,1 0,7*** 25% EEP 14 0,2429 0,1555 0,2*** 25% EEP 14 0,018 0,007 0,0175 431 European Journal of Dentistry 50% EEP 7 0,8 0,1 0,8*** 50% EEP 14 0,1643 0,1336 0,2*** 50% EEP 15 0,01 0,008 0,009***