BackgroundFor success of any indirect metal restoration, a strong bond between cement and the intaglio surface of metal is imperative. The aim of this study is to evaluate and compare the effect of different surface treatment on the tensile and shear bond strength of different cements with nickel–chromium alloy.Material and Methods120 premolars were sectioned horizontally parallel to the occlusal surface to expose the dentin. Wax patterns were fabricated for individual tooth followed by casting them in nickel chromium alloy. 60 samples were tested for tensile bond strength, and the remaining 60 for shear bond strength. The samples were divided into three groups (of 20 samples each) as per the following surface treatment: oxidation only, oxidation and sandblasting, or oxidation, sandblasting followed by application of alloy primer. Each group was subdivided into 2 subgroups of 10 samples each, according to the bonding cement i.e RM-GIC and resin cement. Samples were subjected to thermocycling procedure followed by evaluation of bond strength.ResultsTwo-way analyses of variance (ANOVA) was performed to compare the means of tensile and shear bond strength across type of surface treatment and cement, followed by post hoc parametric analysis. For all tests ‘p’ value of less than 0.05 was considered statistically significant.ConclusionsThe surface treatment of oxidation and sandblasting followed by application of alloy primer offered the maximum tensile and shear bond strength for both RM GIC and resin cement. Resin cement exhibited greater tensile and shear bond strength than RM-GIC for all the three surface treatment methods. Key words:Resin cement, resin modified glass ionomer cement, oxidation, sandblasting, alloy primer, tensile bond strength, shear bond strength, universal testing machine.

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Background: Remdesivir (GS-5734) has emerged as a promising drug during the challenging times of COVID-19 pandemic. Being a prodrug, it undergoes several metabolic reactions before converting to its active triphosphate metabolite. It is important to establish the atomic level details and explore the energy profile of the prodrug to drug conversion process. Methods: In this work, Density Functional Theory (DFT) calculations were performed to explore the entire metabolic path. Further, the potential energy surface (PES) diagram for the conversion of prodrug remdesivir to its active metabolite was established. The role of catalytic triad of Hint1 phosphoramidase enzyme in P-N bond hydrolysis was also studied on a model system using combined molecular docking and quantum mechanics approach. Results: The overall energy of reaction is 11.47 kcal/mol exergonic and the reaction proceeds through many steps requiring high activation energies. In the absence of a catalyst, the P-N bond breaking step requires 41.78 kcal/mol, which is reduced to 14.26 kcal/mol in a catalytic environment. Conclusion: The metabolic pathways of model system of remdesivir (MSR) were completely explored completely and potential energy surface diagrams at two levels of theory, B3LYP/6-311++G(d, p) and B3LYP/6-31+G(d), were established and compared. The results highlight the importance of an additional water molecule in the metabolic reaction. The P-N bond cleavage step of the metabolic process requires the presence of an enzymatic environment.

Since COVID 19 has been declared as a pandemic, regulatory bodies are unsure about its effect on prosthodontic services. Response has varied from complete stoppage of service to rendering only emergency care. This has been majorly due to severity of disease across the globe and lack of preparedness on account of the aggressive nature. But not rendering prosthodontic/dental care is increasing the suffering of patients, burden on emergency department which aren’t able to deliver quality/standard treatment. With new variants continuously emerging, the only option is to re-start prosthodontics practice, albeit with strengthening and modification of preventive measures. Suggestions for preparation of standard guidelines for patient, operator and operatory management during and after the COVID-19 pandemic are detailed in this article.

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Aim: To compare speech intelligibility (SI), nasal resonance, and swallowing ability in maxillectomy patients with a customized obturator to the conventional obturator. Settings and Design: Non-randomized controlled study. Materials and Methods: Forty-eight maxillectomy patients were recruited and assessment of SI, nasal resonance, and swallowing ability was done at three situations: without obturator, with conventional obturator, and with customized obturator. Recordings of unrehearsed conversation, counting from number 1–20 and four sets of Chapel Hill Multilingual Intelligibility Test in the Hindi language were used to assess SI and nasal resonance. SI was evaluated by untrained listeners and graded according to a 6-point scale. Nasal resonance was evaluated by speech pathologists on a 7-point scale of severity. Swallowing ability was evaluated by water drinking test. Statistical Analysis Used: One-way ANOVA, Post hoc Bonferroni and Chi square test. Results: SI and nasal resonance showed a statistically significant difference between any two groups ( P < 0.001). Water drinking time was significantly different between without obturator and with customized obturator ( P < 0.001), but the difference was not statistically significant between without obturator and with obturator ( P < 0.004). Conclusion: SI, nasal resonance, and swallowing ability improved with customized obturator in comparison to the conventional obturator.