The efficacy of photodynamic therapy and sodium hypochlorite in root canal disinfection by a single-file instrumentation technique.

AIM: The aim of this in vitro study was to evaluate the efficacy of photodynamic therapy (PDT) and sodium hypochlorite (NaOCl) in root canal disinfection by a single-file instrumentation technique. MATERIAL AND METHODS: Seventy human single-rooted mandibular premolars were infected with Enterococcus faecalis, Pseudomonas aeruginosa, Staphylococcus aureus and Candida albicans, and divided into seven groups (n=10) according to the protocol of disinfection used. Group 1: 1% NaOCl; Group 2: 5.25% NaOCl; Group 3: saline+PDT; Group 4: 1% NaOCl+PDT; Group 5: 5.25% NaOCl+PDT; Group 6: positive control; Group 7: negative control. For PDT, methylene blue (15µg/mL) remained in the root canal for 2min, followed by irradiation with diode laser. Samples were collected before and after instrumentation and plated in specific media cultures, to assess the presence or absence of microbial growth and determine the average reduction of viable microorganisms. RESULTS: 5.25% NaOCl+PDT resulted in the highest number of specimens with no microbial growth. Also, 1% NaOCl and 1% NaOCl+PDT exhibited similar antimicrobial effects. Saline+PDT was not able to eliminate all microorganisms. There was statistical significant differences between the groups and the microorganisms. CONCLUSION: The association of 5.25% NaOCl with PDT was the most effective treatment against microorganisms from endodontic infection in root canals instrumented by a single-file instrumentation technique. This result shows that PDT can be useful to improve the root canal disinfection.

Evaluation of Microbial Reduction in Root Canals Instrumented with Reciprocating and Rotary Systems.

OBJECTIVE: This in vitro study aimed to evaluate the efficacy of the disinfection of root canal systems carried out with Reciproc(TM) and ProTaper Universal(TM) systems using 1% sodium hypochlorite (NaOCl). METHODS: Forty human single-rooted mandibular premolars were infected with Enterococcus faecalis, Pseudomonas aeruginosa, Staphylococcus aureus and Candida albicans, and twenty were not infected. The specimens were randomly divided into 6 groups (n = 10): Group 1: ProTaper Universal(TM) + 1% NaOCl; Group 2 (positive control): ProTaper Universal(TM) + saline; Group 3 (negative control without microorganisms): ProTaper Universal(TM) + saline; Group 4: Reciproc(TM) + 1% NaOCl; Group 5 (positive control): Reciproc(TM) + saline; Group 6 (negative control without microorganisms): Reciproc(TM) + saline. Samples were collected before and after the completion of specific treatments, and plated in specific media cultures. The Fisher exact test was used for the statistical analysis of differences in terms of presence or absence of microbial growth among groups. For all tested pathogens, significant differences (p < 0.001) were verified between the instrumentation systems used. RESULTS: ProTaper Universal(TM) associated with 1% NaOCl completely eliminated all microorganisms. Microbial growth, however, was observed when Reciproc(TM) was used associated with 1% NaOCl. CONCLUSION: According to the protocol executed for this study, the Reciproc(TM) system associated with 1% NaOCl was not able to completely eliminate E. faecalis, P. aeruginosa, S. aureus and C. albicans from the root canal systems.

Antimicrobial activity of chlorhexidine in root canals instrumented with the ProTaper Universal™ System

Aim: The purpose of the present study was to evaluate the antimicrobial activity of 0.2%, 1%, and2% chlorhexidine in root canals instrumented with the ProTaper Universal™ system. Methods:Fifty human mandibular premolar teeth were infected with a mixture of Candida albicans,Pseudomonas aeruginosa, Enterococcus faecalis and Staphylococcus aureus. The specimens were randomly divided into 5 groups with 10 root canals according to the irrigant used. All root canals were instrumented with the ProTaper Universal™ system. Assessment of the antimicrobial action of the irrigant was performed before, during, and after instrumentation. Data were analyzed statistically by Chi-squared test and the Fisher exact test at 5% significance level. Results: The0.2% chlorhexidine solution was ineffective against all test microorganisms. The 1% chlorhexidinesolution was effective in eliminating P. aeruginosa and C. albicans after the use of the F1 and F3instruments, respectively. The 2% chlorhexidine solution was effective at killing S. aureus, P.aeruginosa and C. albicans after the use of the S1 instrument. There were statistically significant differences (p<0.05) between the concentrations of chlorhexidine and the instruments used.Conclusions: The 0.2% chlorhexidine solution in combination with rotary instrumentation was ineffective against all test microorganisms. The 1% chlorhexidine solution was ineffective against S. aureus and E. faecalis. The 2% chlorhexidine solution was not sufficient to inactivate E.faecalis.