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 ReciprocTM and ProTaper UniversalTM 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 UniversalTM + 1% NaOCl; Group 2 (positive control): ProTaper UniversalTM + saline; Group 3 (negative control without microorganisms): ProTaper UniversalTM + saline; Group 4: ReciprocTM + 1% NaOCl; Group 5 (positive control): ReciprocTM + saline; Group 6 (negative control without microorganisms): ReciprocTM + 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 UniversalTM associated with 1% NaOCl completely eliminated all microorganisms. Microbial growth, however, was observed when ReciprocTM was used associated with 1% NaOCl. Conclusion: According to the protocol executed for this study, the ReciprocTM 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