The effects of antibacterial solutions on microorganisms isolated from infected root canals in vivo

Objective: This study assessed the in vivo antimicrobial activity of NaOCl, Chx, Ca(OH)2, and H2O2 against five different microorganisms: Enterococcus faecalis, Porphyromonas endodontalis, Streptococcus salivarius, Lactobacillus sp., and S. aureus. Study design: Eighty infected teeth in seventy patients with pulpal or periapical pathology were studied. After preparing a standard access cavity. Sterilized paper points were used to take samples from the root canals. These were incubated in test tubes at 37°C for 72 hours. Of the resulting bacteria, the five most frequent strains were examined. The teeth were divided into four equal groups. After preparing the root canal using the step-back technique until a number 55 file, each group was subjected to one of the following irrigation solutions: 2% chlorhexidine gluconate (Chx), 5% NaOCl, Ca(OH)2 in distilled-water, or 3% H2O2. After irrigation, a temporary filling was placed in each cavity. The same irrigation procedure was repeated three and six days later. Then, the microbiologic sampling was also repeated. The chi-squared test was used for statistical comparisons. Results: Of the irrigants tested in this in vivo study, chlorhexidine was the most effective against all the microorganisms isolated from infected root canals, followed by NaOCl, Ca(OH)2, and H2O2. However, differences among the three groups were not statistically significant, except against Enterococcus faecalis (p>0.05). Conclusions: Our results did highly confirm the fact from previous studies that chx with 2% percent is the most effective antibacterial agent after three consecutive irrigations. Furthermore, in vitro and in vivo studies are necessary to assess whether the Chx imparted substantive dissolve organic material. © 2006 Taylor and Francis Group, LLC