The antibacterial efficacy of restorative materials had an important role in preventing the recurrent caries. The objective of this study was to evaluate in-vitro the antibacterial and mechanical assays of Vitremer containing ethanolic extract of propolis (EEP). Materials and methods: I-Antibacterial Assay: The standard strain of Streptococcus mutans and Lactobacillus acidophilus were used for determination of minimum inhibitory concentration (MIC) of EEP/Vitremer. II-Mechanical Assay: A-Shear bond strength (SBS): sixty half-crowns of non-carious extracted 2nd primary molars were placed at standard moulds containing Teflon disc that had 4mm x 3mm central hole and divided into 4 groups (n=15) according to the different EEP concentrations. Group I: 10%, group II: 25%, group III: 50% EEP-Vitremer mixture, and group IV (control): 0% EEP/Vitremer and SBS was assessed using Instron machine. B-Microhardness: Sixty standard disc-shaped specimens were prepared from mixture 0%, 10%, 25%, and 50%, n=15 and nanoindentation value was recorded. Data were analyzed using one-way ANOVA and post-hoc test. Results: Only MIC of 10%, 25%, and 50% mixture showed growth inhibition against S. mutans, compared to 25% and 50% against L. acidophilus. SBS showed that 0% EEP recorded the highest value followed by10% mixture but the difference was not significant (p>0.05), while 25% and 50% reported the lowest values and the differences were significant (p< 0.05). 25% and 50% mixtures recorded the highest significant microhardness (p<0.05). 0% EEP and 10% mixtures displayed no significant differences between them (P>0.05). Conclusions: 25% EEP-Vitremer mixture was the most suitable concentration as it exhibits positive significant antibacterial and mechanical assays.
Keywords: Propolis extract, fluoride-releasing restoratives, inhibition of recurrent caries, antibacterial and mechanical assays.