O efeito da miliamperagem na detecção do canal mesiopalatino de molares superiores em tomografia computadorizada de feixe cônico

Abstract

Introduction: This study tested the accuracy of the Cone Beam Computed Tomography (CBCT) on the detection of the mesiopalatine canal (MPC) treatment of the first permanent molars after the instrumentation and obturation of the root canals with a variation on the milliamperage (mA) values. Methods: The first twenty first permanent molars were divided, initially, in two groups: I) teeth which had three root canals and II) teeth which had four root canals. The canals were prepared with the Protaper Next system until the instrument X3, irrigated with a sodium hypochlorite solution at 2,5% and endodontically treated by the only beam technique and the AH Plus cement. The MPC of group II was not instrumented nor endodontically treated. The images were acquired using the Pax-I 3D tomograph in two distinct moments, after instrumentation and endodontic treatment applying different mA values: 3mA, 5mA and 10mA. The criteria for the analysis of the images were the CBTC images versus the gold standard (tooth). It was attributed a scale of five points: 1) there is no mesiopalatine canal surely; 2) there is no mesiopalatine canal probably; 3) incertitude; 4) there is a mesiopalatine canal, probably; 5) there is a mesiopalatine canal surely. The agreement inter and intra observer was calculated using the Kappa ratio. The responses were analyzed by the calculation of the curve of characteristic of operation of the receptor (ROC), determining the values of sensibility, specificity and accuracy of the images’ modality. The obtained values were compared by the ANOVA test, adopting 5% as the level of significance. Results: The obtained Kappa values indicated good and excellent agreement intra and inter observer, the area below the ROC curve (ASC) varied from 0.91 to 0.97, sensibility from 8% to 95%, specificity from 70% to 90% and accuracy from 77,5% to 90%. There was no statistic difference between the tested protocols. Conclusion: Within the limits of this study, all the protocols can be applied to the detection of MPC in teeth endodontically treated or nor endodontically treated., being recommended the protocols of a minor dose of radiation.