Background and Aim: Equipments and surfaces in dental clinics and centers are always in risk of contamination. When there is no possibility of sterilizing them, fast acting disinfecting agents are used. In this study, antibacterial effect of a new disinfecting solution, named Nanex,against streptococcus mutans and pseudomonas aeroginosa was compared with pure Nano silver solution and Deconex 53 plus.

  Materials and Methods: In this experimental study, in order to determine the effective antibacterial concentration , serial dilution technique ,evaluation of (MIC) and (MBC) were used. Finally bacterial growth was assessed.

  Results: The # 4 solution (containing 100 ppm Nano silver and 2% Deconex) showed the least MIC and MBC for streptococcus mutans. The # 7 solution (containing 133 ppm Nano silver and 1% Deconex) showed the least MIC and MBC for psuedomonas aerogenosa.

  Conclusion: Thus, antibacterial effect of Nanex solution was more potent and effective than pure solution of nano silver and deconex.

  Key words: Disinfectant, Nano silver, Deconex 53 plus, MIC, MBC