The Effect of Sodium Hypochlorite and Chlorhexidine as Irrigant Solutions for Root Canal Disinfection: A Systematic Review of Clinical Trials.

INTRODUCTION: This systematic review aimed to compare the effectiveness of sodium hypochlorite and chlorhexidine for root canal disinfection during root canal therapy. METHODS: A literature search for clinical trials was made on the PubMed (MEDLINE), Web of Knowledge, SCOPUS, and Science Direct databases and in the reference lists of the identified articles up to January 2015. Quality assessment of the selected studies was performed according to the Consolidated Standards of Reporting Trials statement. RESULTS: One clinical trial and 4 randomized clinical trials were selected from the 172 articles initially identified. There was heterogeneity in the laboratory methods used to assess the root canal disinfection as well as in the concentrations of the irrigants used. Therefore, meta-analysis was not performed. Two studies reported effective and similar reductions in bacterial levels for both irrigants. Sodium hypochlorite was more effective than chlorhexidine in reducing microorganisms in 1 study, and another reported opposite findings. Both root irrigants were ineffective in eliminating endotoxins from necrotic pulp root canals in 1 study. Trial design and information regarding randomization procedures were not clearly described in the clinical trials. No study compared laboratory results with clinical outcomes. CONCLUSIONS: The available evidence on this topic is scarce, and the findings of studies were not consistent. Additional randomized clinical trials using clinical outcomes to compare the use of sodium hypochlorite and chlorhexidine during root canal therapy are needed.

Mechanical behavior of pathfinding endodontic instruments.

INTRODUCTION: This study compared the mechanical properties of 3 pathfinding endodontic instruments. METHODS: The test instruments were subjected to mechanical tests to evaluate resistance to bending (flexibility), buckling, cyclic fatigue, and torsional load in clockwise rotation. Data were statistically evaluated by analysis of variance and the Student-Newman-Keuls test for multiple comparisons. RESULTS: In the buckling resistance test, the highest values were observed for C-Pilot files (VDW, Munich, Germany) and the lowest for Scout RaCe (FKG Dentaire, La Chaux-de-Fonds, Switzerland) instruments. In the bending resistance test, the lowest flexibility was observed for the C-Pilot instrument, and no significant difference was observed between Scout RaCe and PathFile (Maillefer/Dentsply, Ballaigues, Switzerland) instruments. The ranking in the fatigue resistance test was the following: PathFile > Scout RaCe > C-Pilot, with statistically significant differences observed in the number of cycles to fracture between all the instruments. In the torsional assay, the angular deflection to fracture decreased in the following order: Scout RaCe > PathFile > C-Pilot. As for the maximum torque values, the ranking was as follows: C-Pilot > PathFile > Scout RaCe. CONCLUSIONS: Findings revealed that the stainless-steel C-Pilot instrument showed increased resistance to buckling but decreased flexibility and cyclic fatigue resistance when compared with nickel-titanium pathfinding instruments. PathFile instruments showed the highest resistance to cyclic fatigue, and Scout RaCe files exhibited the highest angular deflection to fracture. The different mechanical behavior of the instruments indicates that the combined use of stainless steel hand instruments and rotary nickel-titanium instruments during the exploration of narrow curved canals may be necessary to exploit the best performance of each pathfinding instrument.