Avaliação do preparo e da limpeza de canais radiculares ovais longos comparando os sistemas TF Adaptive e Reciproc, por meio da microtomografia computadorizada e da microscopia eletrônica de varredura

Abstract

The action of the endodontic instrument leads to hard-tissue debris. The main goal of the irrigation procedures is its removal. Nevertheless, depending on its kinematics the rotary file can contribute to the removal of hard-tissue debris. The TF Adaptive system (SybronEndo, Orange, CA) combines the rotary and reciprocating movement and the Reciproc system (VDW< Munique, Alemanha) with pure reciprocating movement, removes significant quantities of dentin of the canal wall with more difficulties of pulling out hard-tissue debris. The aims of this study were, using microcomputed tomography: evaluate preparation and quantify hard-tissue debris reduction in long-oval canals comparing TF Adaptive and Reciproc systems; evaluate the effect of passive ultrassonic irrigation (PUI) after preparation with the proposed groups in the accumulation of hard-tissue debris; and correlate the presence of hardtissue debris with smear layer evaluated by scanning eléctron microscope (SEM). Distal canals of thirty-eight lower molars were selected and divided in two groups: G1-TFA (n=19) and G2-RC (n=19). Each specimen was scanned three times: preand post-instrumentation of the root canal; and post-passive ultrassonic irrigation. After reconstruction of the scanned images, a co-registration was done with DataViewer. The softwares CTan and CTvol were used for binarization of the objects of interest, morphometrics alterations and reconstruction of tridimensional models and hard-tissue debris models. Volume increasing, non-prepared surfaces and hardtissue debris after instrumentation were measured. After final irrigation, the root canals were clived in halves at the apical third and analyzed by scanning eléctron microscope related to smear layer. The score system described by Hülsmann et al. (1997) was used. The results showed a non-parametric distribution by D'Agostino test. For that reason, Mann-Whitney test was used to compare the experimental groups and the Kruskall-Wallis test to compare intra-group performance. Dunn test determined which sample was different. Data shows that TF Adaptive removed more dentin in the whole root canal (p<0,05). There was no significant statistic difference comparing non-prepared surfaces between the systems (p>0,05). Related to hardtissue debris and reduction of hard-tissue debris after passive ultrassonic irrigation, there was no significant difference between TF Adaptive and Reciproc. The PUI reduced significantly hard-tissue debris, except for the apical third. The scanning electron microscope (SEM) showed a non-homogeneous smear layer covering the canal dentin walls, specially the Reciproc group. It was concluded that no system completely prepared the dentin walls of long-oval root canals and the passive ultrassonic irrigation decreased hard-tissue debris about 60-70% in the evaluated systems. SEM analysis reported no correlation between hard-tissue reduction and smear layer.