Avaliação in vitro da remoção da smear laer intracanal pelo ácido metilglicinodiacético

Abstract

The objective of this study was to evaluate the efficacy of 20% methylglycinediaacetic acid solution in the removal of the intracanal smear layer, using a scanning electron microscope (SEM), longitudinally and quantitatively. The chemical-mechanical preparation of the root canals of human upper central incisors was performed with the ProTaper system up to the instrument F5 and 2,5% NaOCl as an irrigating solution. The teeth were then cleaved and the dentin surface analyzed in the SEM under low vacuum. Images were obtained with 1000x magnifications of the cervical, middle and apical thirds of areas previously determined and completely covered by smear layer. The teeth were reassembled and divided into two groups that received the different solutions for final cleaning of the root canal for 3 minutes: G1 - MGDA and G2 - EDTA. After the final irrigation, the tooth halves were again separated and prepared for analysis of the dentin surface in the SEM in high vacuum. Images with the same magnifications were obtained from the same areas previously evaluated and, through Image J software, the percentage of the area of the open dentinal tubules was calculated in relation to the total area ofthe image. Test t was used for comparison between groups and ANOVA between the thirds of the root canal. The level of significance was 5%. Data presented normal distribution (Shapiro-Wilk test). There was no statistically significant difference in the efficacy of the root smear layer removal between the solutions and nor of their action between the thirds. It is concluded that MGDA solution may be an alternative to the use of EDTA in Endodontics and its properties should be investigated.