Análise do desvio apical e das características de superfície dos instrumentos reciprocantes na reintervenção endodôntica – estudo in vitro.

Abstract

The aim of this study was to analyze the apical deviation and surface characteristics of the instruments WaveOne Gold® and Reciproc Blue® after endodontic reintervention in simulated canals. Initially, initial images of 42 enumerated blocks were obtained, containing the simulated curved channels, and the instruments WaveOne Gold® Medium (WOGM) and Reciproc Blue® R40 (RB) were evaluated in a Scanning Electron Microscope (SEM) before being used. After instrumentation, the simulated canals were filled and new images were obtained. Then, all blocks were separated into two groups with 21 specimens each, as follows: Group 1 – specimens that underwent endodontic reintervention with the WOGM system; Group 2 – specimens that underwent endodontic reintervention with the RB system. Each instrument, both from the WOGM group and from the RB group, was used in 3 blocks to remove gutta percha, and after each use, new electromicrographs were taken to evaluate the surface characteristics. Soon after the reintervention, all blocks were photographed again and the images received different colors, with red color for images after obturation and green for images after re-intervention with WOGM inserts and black color for re-intervention after the use of RB instruments. The image overlay method was used, through which the distance between the wear on the inner wall of the canal and the wear on the outer wall of the simulated reinstrumented canals was determined. To assess the surface of the instruments before and after use in the SEM, electromicrographs were taken at the tip of the instrument, at 2mm and 4mm from the tip, with a magnification of 190X. Scores were established by observing the presence of irregular edges, grooves, stains or adhered materials, microcavities and burrs. There was no statistically significant difference between the groups regarding apical deviation after reintervention, only when comparing the 1st millimeter of the WaveOne Gold Medium group with the 3rd and 5th millimeter of the Reciproc Blue R40 group (p < 0.001). When the defects and deformations were evaluated, the WaveOne Gold Medium instruments presented a statistically higher amount of defects and deformations (p < 0.001) when compared to the Reciproc Blue instruments before and after the second use. It was concluded that both systems tested promoted similar apical deviation values, and the WaveOne Gold Medium system showed a greater presence of defects and deformations on its surface after different times of use.