Comparative Assessment of Qmix as Endodontic Irrigant on Reversal of Bond Strength in Teeth Subjected to Irradiation: An Scanning Electron Microscope Study

Abstract

The aim of this current study was to compare and evaluate the reversal efficacy of Qmix and chitosan-based irrigation materials quantitatively through the assessment of the push-out bond strength of bioceramic sealer employing universal testing machine and to qualitatively analyze the sealer/dentin interface by scanning electron microscope (SEM) in the teeth subjected to fractioned radiation. Ninety single-rooted straight human maxillary central incisors were randomly divided into six groups (n = 15) where in three groups comprise Chitosan, Qmix, and EDTA/sodium hypochlorite which were not exposed to irradiation while other three groups were challenged with irradiation protocols. Root canals were prepared with ProTaper universal system and all the samples were irrigated according to the final irrigation protocols and obturated with bioceramic sealers. Dentin slices were prepared with 1 mm thickness from each root third for the estimation of bond strength of sealers to dentin. Qualitative assessment of the sealer-dentin interface was done by scanning electron microscopy. Bond strength data were scrutinized by independent t-test and failure modes using the Chi-square test. Significantly lower bond strength (p <0.05) was recorded after irradiation compared with nonirradiated group. To quantify the results irrigation protocols, Qmix had highest bond strength followed by chitosan and EDTA/sodium hypochlorite group irrespective of irradiation status. Bond strength values reduced after irradiation in all root thirds irrespective of the irrigation materials. Scanning electron microscope images revealed traces of repair process for Qmix-based irrigation materials than the chitosan-based materials for both irradiated and nonirradiated specimens. All the irrigation materials employed in this study had good bond strength. The specimen irrigated with Qmix had comparatively higher bond strength than the chitosan-based materials. The teeth subjected to irradiation challenge were associated with a decrease in the push-out bond strength of sealers to intraradicular dentin with formation of more gaps and fewer tags at the sealer/dentin interface. Selection of ideal irrigation protocols still remains a challenge for the clinical practitioners, and this study explored the utilization of novel materials used for irrigation, especially in the teeth subjected to radiation.