New irrigant solution in Endodontics: test in vitro

Objectives: There are several irrigation solutions used in endodontics. Sodium hypochlorite and chlorhexidine are the most common endodontic irrigants among those in commerce today. Some studies show that peracetic acid is a bactericide too, and it is less toxic than sodium hypochlorite. This study wants to compare antimicrobic properties of these endodontic irrigants. Materials and methods: 26 extracted teeth were prepared EDTA and water were used as irrigants. Every canal was reamed 1 mm beyond apex. Apexes have been subsequently sluices with resin polyester (Kristaal, Hobbyland) in order to avoid the spillage of bacteria. Sterilization of each specimen in autoclave to 121°C for 25 min.. 24 specimens were divided into 3 groups in a random way and the other 2 teeth were used as control. A suspension of Enterococcus faecalis, Staphylococcus epidermidis, Staphylococcus aureus, Streptococcus miller and Actinomyces odontolyticus, 7,5 x 106 CFU/ml concentrated, was prepared. This broth dilution was inoculated into the root canals and after incubation specimens were divided into: - group A: Sodium hypochlorite 5% (Niclor, Ogna) - group B: peracetic acid 5% (25 g of Peracetic plus, Germo, + 0,5 l of water) - group C: chlorhexidine 0.2% + cetrimide 0.2% (Cetrexidin, Vebas) Every solution worked for 1 min. 50 ìl of sterile saline solution were inoculated into each canal and than the solution was sown into a blood agar plate (Schaedler). After incubation bacterial colonies were calculated. Results: -group A: only 1 agar plate presented 10 bacterial colonies -group B: no bacterial colonies in any agar plates -group C: 4 agar plates without bacterial colonies and 4 presenting respectively 2, 3, 4 and 65 bacterial colonies. Conclusion: Sodium hypochlorite and peracetic acid had a similar behavior; they killed almost every bacterium. Cetrexidin resulted the less efficacious endodontic solution among those we analyzed.