Evaluation of the expression of image artifacts created by different intracanal medications in cone beam computed tomography and microcomputed tomography

Abstract

This study will evaluate the expression of image artifacts caused by the X-ray beam hardening phenomenon in imagens obtained by cone beam computed tomography, with different scanning and reconstruction protocols, using microcomputed tomography images as the reference standard. Human maxillary canines (n=40) will be selected, which after root canal biomechanical preparation with the WaveOne Gold Large reciprocating system, will be randomly divided into four groups (n=10) according to the intracanal medication used: G1 - calcium hydroxide paste - Ultracal XS; G2 - bioceramic-based medication - BioC-Temp; G3 - calcium hydroxide paste with iodoform - Metapex and G4 - calcium hydroxide paste with barium sulfate - Metapaste. The specimens will be sealed with temporary restorative sealer and stored at 37ºC and 100% humidity, for 7 days. Then, they will be scanned by microCT (SkyScan 1174) and by 2 different CBCT devices in high (HR) and standard (NR) resolution protocols: (1) Eagle X3D and (2) OrthoPantomograph OP 300. FIJI ImageJ software will be used for standardization and registration of the obtained images. The images of the axial, sagittal and coronal reconstructions were evaluated quali-quantitatively by two calibrated examiners, through assignment of the following scores regarding the types of image artifacts caused by X-ray beam-hardening (dark streaks, hypodense areas and distortion): (1) definitely absent; (2) probably absent; (3) unsure; (4) probably present; and (5) definitely present; and the scores to evaluate the possibility of using the images for diagnostic purposes in Endodontics: (0) No and (1) Yes. Qualitative data will be evaluate using the Fleiss' Kappa test and the devices will compare to each other for each type of reconstruction (axial, sagittal and coronal) separately. Correction for the simultaneous hypothesis will perform according to the `idák test, with probability level of 95%.