ABSTRACT
BACKGROUND: The isthmus and irregularities present in the root canal system are potential areas for debris accumulation areas and therefore the seach for devices and solutions to improve cleaning of these areas is of utmust importance. This study evaluated, by micro-computed tomography, the efficiency of 37% phosphoric acid solution with that of 17% EDTA in the removal of smear layer and accumulated hard tissue debris (AHTD) after canal preparation. METHODS AND MATERIALS: Twenty-six mesial roots of mandibular molars were subjected to microtomographic scanning using the SkyScan 1173 X-ray microtomograph at a resolution of 14,97 µm. The canals were prepared using Reciproc R40 instruments, 6% NaOCl and EndoVac System® to irrigation/aspiration. After instrumentation, the specimens were divided into two groups: 37% phosphoric acid solution or 17% EDTA. RESULTS: The results demonstrated that 37% phosphoric acid was significantly more effective in removing smear layer and AHTD than 17% EDTA (Mann-Whitney, P <0.05). It was shown that both 37% phosphoric acid and 17% EDTA are effective agents in the removal of smear layer and debris, but better results were obtained with the use of 37% phosphoric acid. CONCLUSION: The results suggest that this solution can be a potential alternative to remove smear layer after root canal preparation.
ABSTRACT
O objetivo do estudo foi avaliar, por microtomografia computadorizada, a eficiência da solução de ácido fosfórico 37% e do EDTA 17% na remoção de smear layer e debris de tecidos mineralizados acumulados (DTMA) após o preparo químico-mecânico. Métodos: Vinte e seis raízes mesiais de molares inferiores foram microtomografadas em três momentos distintos: exame inicial, após preparo-químico mecânico e após remoção de smear layer pelo emprego do microtomógrafo Skyscan 1173 utilizando resolução de 14,97 µm. Os canais foram preparados utilizando limas Reciproc R40, NaOCl 6% e o Sistema EndoVacï para irrigação/aspiração. Após preparo, os espécimes foram divididos aleatoriamente em dois grupos, de acordo com a solução desmineralizante utilizada: solução de ácido fosfórico 37% ou EDTA 17%. O software CTan foi utilizado para análise volumétrica e o software Seg3D para reconstruções tridimensionais. Os dados foram analisados através do teste Mann-Whitney utilizando α=0.05 como nível de significância estatística. Resultados: A diferença entre os volumes após remoção de smear layer e após o preparo químico-mecânico demonstrou que o ácido fosfórico 37% foi significativamente mais eficiente na remoção de smear layer e DTMA que o EDTA 17% (p<0,05). Conclusões: Demonstrou-se que ambos, ácido fosfórico 37% e EDTA 17%, são agentes eficazes na remoção de smear layer e debris, porém melhores resultados foram obtidos com o uso do ácido fosfórico 37%. (AU)
Introduction: The aim of this study was to evaluate, by microcomputed tomography, the efficiency of 37% phosphoric acid solution with that of 17% EDTA in the removal of smear layer and accumulated hard tissue debris (AHTD) after canal preparation. Methods: Twenty-six mesial roots of mandibular molars were subjected to three microtomographic scannings: initial scanning, after instrumentation and after smear layer removal using the SkyScan 1173 X-ray microtomograph at a resolution of 14,97 µm. The canals were prepared using R40 Reciproc instruments, 6% NaOCl and EndoVac Systemï to irrigation/aspiration. After instrumentation, the specimens were randomly divided into two groups according to the demineralizing solution used: 37% phosphoric acid solution or 17% EDTA. CTAn software was used for volumetric analysis and Seg3D software was used for 3D model reconstructions. Data were analyzed using Mann-Whitney test using α=0.05 as level of statistical significance. Results: The difference between the volumes after removal of smear layer and after chemical-mechanical preparation demonstrated that 37% phosphoric acid was significantly more effective in removing smear layer and AHTD than EDTA 17% (p <0.05). Conclusions: It was shown that both 37% phosphoric acid and 17% EDTA are effective agents in the removal of smear layer and debris, but better results were obtained with the use of 37% phosphoric acid. (AU)
