Antimicrobial and toxic effects of established and potential root canal irrigants.

Three dilutions of the commonly used irrigant sodium hypochlorite (0.5%, 2.5%, and 5.25%) and the potential irrigants Peridex, chlorhexidine gluconate (0.12%), and Therasol were tested. Alcohol and saline served as controls also. The in vitro portion of this study used four different microorganisms (Streptococcus mutans, Peptostreptococcus micros, Prevotella intermedius, and Porphyromonas gingivalis) to determine antimicrobial effect. Presterilized 7-mm diameter Whatman paper disks soaked with the test solution were prepared, and disks were placed onto the previously seeded agar petri dishes. Each dish was incubated aerobically or anaerobically according to the microorganisms used. An in vivo animal model (guinea pig) was used to examine subcutaneous local tissue reactions using the same materials; 0.1 ml of each test solution was injected subcutaneously into predetermined locations on the animal dorsum. Test site histological examination was done 2 h, 2 days, and 2 wk after the injections. The results of this comparative study indicate Peridex (chlorhexidine gluconate) and Therasol may have good potential for endodontic usage.