The effects of different antibacterial solutions to microorganisms isolated from infected root canals

To eliminate the microorganisms from the root-canals, which are one of the most important etiologic factors in pulpal and periapical pathosis, biomechanical preparation with the aid of chemical disinfections, are necessary. Chemical agents to be used for irrigation of root canal should not only be a good solvent for infected-tissue-remnants, but also have high antibacterial activity. This study has been carried out to investigate the antibacterial effect of four different irrigation solutions on the bacteria isolated from the infected-root-canal. Our study has been performed on 80 infected-teeth which were diagnosed as pulpal and/or periapical pathosis. After the preparation of a standardized-access-cavity, a number of 20 K-type file was inserted into the root canal until the root-apex. Sterilized-paper points were used to take samples from root-canals, and then they were incubated in test tube at 37°C for 72 hours. Of the bacteria planted, five-strains which had higher-growing-number were decided to include in this study. All patients were equally divided into 4 groups including 20 patients in per-group. After the preparation of root canal with step-back technique until the number of 55 file, each group was subjected to one of these following irrigation-solutions; a- 5 % sodium hypochlorite, b- 2 % chlorhexidine gluconate, c- a mixing of calcium hydroxide powder with distilled-water, and d- 3 % hydrogen peroxide. After the irrigation, a temporary filling was placed on each cavity-access. Same procedure concerning canal irrigation was repeated at 3 rd and 6th day, and subsequently, microbiologic samples method was also repeated. To statistically explore antibacterial efficiencies among 4 different irrigation solutions, a chi-square test was used. Of the irrigation solutions used in this in-vivo study, chlorhexidine was the most effective against the microorganisms isolated from the infected-root-canals, and followed by sodium hypochlorite, calcium hydroxide and hydrogen peroxide. However, the difference among three groups was not statistically significant except of the efficiency on E. faecalis (p>0.05). There was no significant difference between two groups with respect to efficiency on E faecalis (p>0.05). Key words: irrigation solution, antibacterial activity, infected-root-canal.