O efeito do uso de sistemas rotatórios e reciprocantes de lima única na capacidade de modelagem e na qualidade da obturação do sistema de canais radiculares de molares decíduos

Abstract

This study aimed to evaluate the effect of rotary and reciprocating systems on shaping and obturation quality in deciduous molars. For this purpose, primary molars (20 teeth and 60 root canals) were selected and scanned using micro-computed tomography (microCT) (Bruker-microCT, Kontich, Belgium), at 50kV, 800mA, reconstructed with NRecon software v. 1.6.8.0 (Bruker micro-CT, SkySCAN, Belgium). The groups were defined after matching (5 teeth and 15 root canals per group) and subjected to instrumentation protocols using a control group with manual Kerr files (21 mm) and the Reciproc Blue® R25 (25/0.08v), Hyflex EDM® (25/~), XP Endo Shaper® (25/0.01v) systems. After instrumentation, the teeth were scanned again with microCT, obturated with Lentulo spiral and OZE, and then reanalyzed with microCT. The percentage of unprepared dentin area, volume, surface area, percentage of dentin removed, perforations, and obturation quality through voids were evaluated. The instrumentation time was also assessed. Data were tabulated in SPSS 20.0 (IBM, IL, USA) and subjected to Shapiro-Wilk test for normality evaluation and subsequently to Kruskal-Wallis and Mann-Whitney tests (α = 5%). The homogeneity of teeth in different groups was confirmed by analyzing the initial dentin surface and volume (p > 0.05). A higher percentage (p < 0.05) of unprepared area was demonstrated in the mesiobuccal canal in the Reciproc Blue® group with a mean 2.50% (CI: 2.10-9.40%) of when compared with hand file instrument with a mean of 5.55% (CI: 3.15-11.10%) and palatal canal also presented lower percentage (p < 0,05) of unprepared area in Reciproc Blue® with a mean of 2.94% (CI: 1.40-5.70%) when compared to hand filegroup with a mean of 3.30% (1.10-15.46%). All root canals showed an increase in surface area and volume after instrumentation (p < 0.05) within the groups, except for the volume of the mesiobuccal canal in the Hyflex EDM® group. There was no difference between the percentages of dentin removed (p>0.05). The hand file group showed a greater reduction in the mesiobuccal dentin thickness in the 4mm of furcation when compared to Hyflex EDM® (p = 0.026) and XP Endo Shaper® Group (p = 0.027). The XP Endo Shaper® and Reciproc Blue® groups presented perforations in 20% and 6% of the canals, respectively. The hand file instrumentation resulted in higher time than other systems (p < 0.5).Similar voids were observed when comparing all groups (p > 0.05), except for the distobuccal canal, which showed larger voids in the Hyflex EDM® group compared to the hand file group. It is concluded that all evaluated systems can be effectively used in deciduous teeth; however, the XP Endo Shaper® system should be used with caution due to causing perforations, since it was associated with a greater occurrence of perforations.