Objective: The purpose of this study was to determine the ability of a methacrylate resin dentin bonding agent to adhere to the dentin surfaces of prepared and conditioned root canals with either 32% phosphoric acid (PA) or 17% ethylenediaminetetraacetic acid (EDTA).
Methods: Prior to the application of the methacrylate resin, the root canals of 54 intact, caries-free, sin- gle-rooted, de-crowned, extracted human maxillary incisor and canine teeth were endodontically prepared and conditioned with either 32% PA or 17% EDTA or with distilled water as the unconditioned control. The resin-treated roots were cross-sectioned at three levels and scanning electron microscope (SEM) imaged for circumferential views of the root canals at 60-90× magnification and site-specific views at 250× magnification, and then randomly coded for independent and blind evaluation by four calibrated examiners. The circumfer- ential surface of the root canals that showed no resin adhesion were digitally measured and subtracted from the digitally measured total root canal circumference, and resin adhesion was expressed as a percentage of the circumference.
Results: The mean percentages of resin adhesion were 97% for the PA group, 94% for the EDTA group, and 76% for the control group. There were statistically significant differences among the PA, EDTA, and control groups.
Conclusion: Root canals conditioned with 32% PA or 17% EDTA had more resin adhesion than unconditioned root canals. Root canals conditioned with 32% PA had more resin adhesion than those conditioned with 17% EDTA.