Success of endodontic treatment depends on complete disinfection of the root canals. Root canal irrigants have a major role in complete disinfection of the root canals. Chemical root canal irrigants are more or less toxic to the oral environment. In this study, naturally derived leaf extracts of A. muricata and S. glauca are compared with sodium hypochlorite for its effectiveness against E. faecalis - the most common pathogen found in the root canals.

Aim: To evaluate and compare in vitro the dentinal crack formation in root canal dentin after root canal instrumentation with hand K-Flex files, ProTaper Next, and self-adjusting engine-driven files. Materials and methods: Ninety-two human mandibular first molar teeth were randomly divided into four groups (n = 23) as per the instrumentation protocol: group I-unprepared teeth (control); group II-hand K-Flex files (Sybron Endo); group III-ProTaper Next X1 and X2 (Dentsply Maillefer); group IV-self-adjusting file (ReDent Nova, Israel). All the roots were sectioned perpendicular to the long axis of the tooth at 9 mm, 6 mm, and 3 mm from the apex and thereby obtaining sixty-nine samples, which were then subjected to a stereomicroscopic examination for detection of dentinal cracks. Statistical analyses were done using the Chi-square test with SPSS (version 19), and p value was set at p < 0.05. Results: Statistically significant differences were seen between the instrumented groups. No dentinal cracks were found in the unprepared roots and those prepared with hand K-Flex files (0/23). Self-adjusting-file-instrumented group showed significantly less incidence of crack formation when compared to the ProTaper Next group with p = 0.001. Conclusion: Self-adjusting file is an efficient engine-driven NiTi instrument for root canal instrumentation with the least occurrence of crack formation in the root canal dentin compared to the ProTaper Next system. Clinical significance: The introduction of NiTi rotary file systems has metamorphosed the endodontic treatment by their better cutting efficiency and cleaning potentiality. Yet, evidenced-based clinical studies are to be conducted on the incidence of microfractures that can lead to vertical root fractures, which will be produced irrespective of the motion kinematics and design feature and thereby compromising the clinical maintenance of the endodontically treated teeth.

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Tooth bleaching helps to improve the appearance of discolored teeth. But the use of acidic food can lead to increased erosion after bleaching. Remineralizing treatment with a remineralizing agent is capable of reestablishing the lost enamel surface hardness after bleaching. In this study, changes in microhardness were analyzed upon the application of a remineralizing agent after subjecting the enamel surfaces to bleaching and erosive challenge. Aim: The aim of this study is to evaluate the effect of a remineralizing agent on bleached enamel surfaces subjected to erosive challenge. Materials used: (1) 35% carbamide peroxide (Opalescence PF, Ultradent)-a bleaching agent; (2) Remin Pro-a remineralizing agent; (3) 1% citric acid solution-an erosive agent. Materials and methods: Samples were divided into three groups and subjected to bleaching and erosion treatment. Group I-treated with 35% carbamide peroxide then treated with 1% citric acid solution; group II -treated with 35% carbamide peroxide and a remineralizing agent followed by 1% citric acid solution; group III-without bleaching with 1% citric acid solution. The sample size calculated using the statistical package G*power (3.1.5) with a level of significance of 0.05. The sample size obtained is n = 15, 5 samples per group. GI, GII, and GIII were subjected to the Vickers microhardness analysis. Loss of surface hardness loss (% SHL) was analyzed. Result: The lowest % SHL is in group II-24.718 when compared with group I-35.048. Conclusion: Post-bleaching application of a remineralizing agent helps to decrease the effect of erosion occurring as a consequence of bleaching.All the samples (n = 15) were submitted to an initial surface microhardness test. For this purpose, a microdurometer with a 1-7