RESUMEN
Streptococcus mutans and sanguinis are etiologic agents of dental caries. The use and search for drugs derived from plants have accelerated in the recent years. The aim of this study was to compare the antibacterial effects of ethanolic walnut leaf extract with chlorhexidine mouth rinse on these bacteria. In this experimental study, after collection and extraction of the plant, the ethanol extract of walnut leaves together with chlorhexidin was examined for antibacterial activities on Streptococcus mutans and Streptococcus sanguinis using the agar-diffusion and microdilution methods. Amikacin [30 micro g] was used as an antimicrobial positive control. Assessment of total phenolic components was carried out using Folin-Ciocalteu method. Data were collected as a check list based on observation of laboratory results and analyzed by SPSS 16 software using the Man-Whitney statistical test. The results showed that the Minimum Inhibitory Concentration [MIC] for ethanolic extract of walnut leaf was 125 and 15.6 mg/ml for Streptococcus mutansand Streptococcus sanguinis, respectively. There was significant different between ethanolic extract and chlorhexidine on the inhibition zone for Streptococcus mutans [p=0.000] but no significant difference was observed for Streptococcus sanguinis [p=0.058]. Deal of the phenolic component was 410 +/- 14.43 mg/g. These findings showed that walnut leaves have antibacterial effects on these two bacteria and may be substitute for protection and treatment against dental plaque due to these microorganisms