Effectiveness of 1 mol L-1 citric acid and 15% EDTA irrigation on smear layer removal

Aim The aim of this study was to evaluate in vitro the cleansing and smear layer removal capability of alternate canal irrigation with citric acid and NaOCl. Methodology Eighty-one teeth were divided into three groups on the basis of the type of instrumentation, namely, manual stainless steel, Ni-Ti mechani zed Profile .04 taper or MACXim. The groups were further divided on the bas is of irrigation protocol: 5% NaOCl alone, NaOCl alternated with 1 mol L-1 citric acid solution or a combination of 15% EDTA and Cetrimide solution. A fter longitudinal sectioning, dentinal walls were microphotographed with sc anning electron microscopy at x300 and x1000 magnifications. Qualitative an d quantitative cleansing level evaluations were performed using computerize d Image analysis software. Data were statistically evaluated using Kruskal- Wallis analysis and t-test. Results Qualitative evaluation at x300 and x1000 showed no statistically si gnificant differences in cleansing ability between citric acid, EDTA and Na OCl groups. Quantitative evaluation of smear layer removal, measured as ope n tubules/total dentinal surface ratio, showed that 1 mol L-1 citric acid s olution was comparable to EDTA (11.97% vs, 10.36%) (NS); in samples treated with Profile .04 taper instruments citric acid was most effective (16.17%) , whilst in the group treated with manual instrumentation EDTA and Cetrimid e were the most effective (11.94%). Specimens irrigated with 5vo NaOCl demo nstrated significantly more cleansing than (P < 0.001). those obtained in t he other two groups Conclusions 1 mol L-1 citric acid solution was as effective in removing sme ar layer as EDTA, but was superior in specimens treated with ProFile.04 tap er instruments.