INTRODUCTIONThe endodontic therapy consists of elimination of bacterial load in the pulpal canal and filling of the entire root canal system three dimensionally. The gutta-percha with the sealer should provide seal both apically and laterally, thus preventing contamination of the root canal [1,2].Incomplete obturation of the root canal accounts for 58% of endodontic failures [3,4]. The incomplete obturation may be because of incomplete instrumentation or improper obturation technique [5]. The sealers used should fill the discrepancies between the canal wall and the gutta-percha; act as a lubricant and aid in seating the gutta-percha cones. The sealers should also fill the patent accessory and lateral canals, entomb the bacteria present within the dentinal tubule and allow for the repair of the periapical tissue [6,7].Recently, there has been improvement in the formulation of root canal sealers. The traditional zinc oxide eugenol sealers have been replaced with resin-based, silicone based, MTA based and bioceramic based sealers. In particular, bioceramic-based sealers are gaining popularity because of their alkaline pH, chemical stability within the biological environment, lack of shrinkage and are more biocompatible [8,9].Calcium hydroxide based sealers have been introduced to have both antibacterial action and to stimulate a sterile biological closure of apical region [10]. The limitation of these sealers is that on contact with moisture the setting time is decreased which would result in poor adaptation to canal walls [6].MTA fillapex, MTA Obtura, Endo-CPM sealer and ProRoot Endo sealer are the most commonly available MTA based sealers. These sealers are reported to have good biocompatibility and sealing properties equivalent to epoxy-based root canal sealer or the pulp canal sealer. When in contact with simulated body fluids, MTA based sealers release calcium and encourage the deposition of apatite crystals [10,11].EndoREZ (Ultradent Products Inc, South Jordan, UT) is a dualcured radiopaque urethane dimethacrylate based sealer that is used with resin coated gutta-percha. This system does not employ dentin adhesives and relies on penetration of hydrophilic resins into the dentin tubules after removal of smear layer. Recently, the bond strength and apical seal of the endorez sealer was improved using dual cured self-etching primer/adhesives [12]. The Endorez system has been shown to have satisfactory sealing ability and an easy delivery system [13].Endosequence BC sealer and iRootSP root canal sealer are bioceramic based root canal sealers which are available as a premixed white hydraulic cement paste and usually contain calcium silicate and/or calcium phosphate [14].The most common technique for evaluating the sealing ability of the root canal sealer is the dye penetration technique which is based on the linear measurement of the dye penetration between the root filling and the canal wall. The study aimed at evaluating the sealing ability of zinc-oxide eugenol, Sealapex, AH plus, EndoRez, MTA Plus and Endosequ...

A BSTRACT Aims and Objectives: The aim of this study was to evaluate the effectiveness of three different caries excavation methods using micro-computed tomography (micro-CT). Materials and Methods: Fifteen freshly extracted human molar teeth with occlusal dentinal caries were selected. The teeth were sectioned longitudinally into two halves and were randomly divided into three groups ( n = 10) depending on the caries removal technique: Group 1: tungsten carbide (TC) bur, Group 2: cerabur (CB), and Group 3: Excavus (EX) tipEX). A preoperative micro-CT scan of all the samples was taken. The caries excavation procedures were carried out followed by postoperative micro-CT scan. The preoperative and postoperative scans of each tooth were analyzed for caries removal effectiveness (CRE), mineral density (MD), and minimal invasiveness potential (MIP) using Avizo 9.4 software (Thermo Fisher Scientific, Germany). Statistical analysis was conducted by applying three-way analysis of variance and independent sample t -test using the Statistical Package for the Social Sciences software, version 20.0 (IBM Corporation, USA). Results: Among the three groups, the TC group had the smallest RC/IC (residual caries/initial caries) ratio, highest mean MD at the cavity floor, and highest MIP. The EX group significantly had the highest RC/IC, lowest mean MD, and lowest MIP. Both the CRE and MIP parameters of CB group were acceptable (RC/IC = 0.08, mean MD = 1.09g/cm 3 , and MIP = 1.09). Conclusion: As compared with the three excavation methods, CBs can be considered as an alternative to TC burs because of its MIP and complete removal of infected carious dentin.

No abstract