The appearance of root canal surfaces in teeth previously treated using resorcinol-formaldehyde resin: a preliminary SEM investigation.

OBJECTIVE: To evaluate the root canal surfaces in teeth previously treated using RF resin by SEM. MATERIAL AND METHODS: 20 distal roots of mandibular molars with typical discoloration of tooth crown were used in this study: 10 brownish - red and 10 non-colored roots. The roots were removed from the crowns, splinted longitudinally and subjected to SEM in a back-scattered electron mode. RESULTS: In discolored root samples canal walls appeared without smear layer and varying amount of remaining debris, the observed morphology of dentine was ordinary. In the non-colored root samples the dentin profile revealed: in coronal third of the root just few open dentinal tubules were detected, while in the middle and apical thirds no open dentinal tubules were observed, dentin profile was similar to sclerotic dentin. The multiple dentinal defects were detected in all samples, however significantly more dentinal defects were found in the colored roots. The RF paste was well adhered to the root canal dentine and multiple tags of RF resin penetrating deeply into the dentinal tubules were detected. CONCLUSIONS: The surfaces of the root canal walls of the teeth treated using RF paste exhibits usual appearance and ordinary dentin morphology in colored roots while the dentin of non-colored samples has the profile of sclerotic dentin. Multiple dentinal defects could be determined by damaging effect of RF resin on dentin. The adaptation and adhesion of RF paste to the dentin, capability to penetrate into dentinal tubules is comparable with the modern resin based sealers.