Faculty Publications
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Item Cytocompatibility by MTT assay and platelet adhesion of Ti and Ti-6Al-4V coated with hydroxyapatite in different plasma gas atmospheres(Jaypee Brothers Medical Publishers (P) Ltd 4838/24 Ansari Road, Daryaganj New Delhi 110 002, 2017) Kotian, R.; Rao, P.P.; Madhyastha, P.; Shobha, K.L.; Satish Rao, B.S.S.; Ginjupalli, K.Aim: This study was performed to evaluate the biocompatibility of pure titanium and Ti-6Al-4V metals coated with hydroxyapatite (HA) by plasma spray using different plasma gas atmospheres. Materials and methods: The cell viabilities for each HA-coated sample in an atmosphere of argon, argon–hydrogen, nitrogen, and nitrogen–hydrogen were studied using MTT assay and platelet adhesion test. Results: The mean cell viabilities by MTT [3-(4,5-dimethylthiazol- 2-yl)-2,5-diphenyltetrazolium bromide] assay of samples coated with HA in argon–hydrogen plasma atmosphere showed maximum cell viability at different time intervals compared with other coating atmospheres of argon–hydrogen, nitrogen, and nitrogen–hydrogen. A statistically significant value of cell viability (p < 0.001) was observed between and within the groups of argon, argon–hydrogen, nitrogen, and nitrogen–hydrogen plasma gas atmosphere. The platelet adhesion study showed agglomerates of platelet cells in some isolated regions of HA for all atmospheres. Significance: The results obtained in this study can serve as a guide for the development of new Ti-based HA-coated implants in different plasma gas atmospheres. © 2017, Jaypee Brothers Medical Publishers (P) Ltd. All rights reserved.Item X-ray diffraction analysis of hydroxyapatite-coated in different plasma gas atmosphere on Ti and Ti-6Al-4V(Medknow Publications subscription@eurjdent.com B9, Kanara Business Centre, off Link Road, Ghatkopar (E) Mumbai 400 075, 2017) Kotian, R.; Rao, P.P.; Madhyastha, P.Objective: The aim is to study the effect of plasma working gas on composition, crystallinity, and microstructure of hydroxyapatite (HA) coated on Ti and Ti-6Al-4V metal substrates. Materials and Methods: Ti and Ti-6Al-4V metal substrates were coated with HA by plasma spray using four plasma gas atmospheres of argon, argon/hydrogen, nitrogen, and nitrogen/hydrogen. The degree of crystallinity, the phases present, and microstructure of HA coating were characterized using X-ray diffraction and scanning electron microscopy. Results: Variation in crystallinity and the microstructure of HA coating on plasma gas atmosphere was observed. Micro-cracks due to thermal stresses and shift in the 2? angle of HA compared to feedstock was seen. Conclusion: Plasma gas atmosphere has a significant influence on composition, crystallinity, and micro-cracks of HA-coated dental implants. © 2017 European Journal of Dentistry.Item Interfacial bonding of plasma-coated hydroxyapatite on titanium and Ti-6AI-4V(Jaypee Brothers Medical Publishers (P) Ltd 4838/24 Ansari Road, Daryaganj New Delhi 110 002, 2018) Kotian, R.; Rao, P.; Madhyastha, P.Aim: The study aimed to understand the interfacial bonding and diffusion of elements between substrate metal and HA-coated titanium implants in different plasma gas atmosphere. Materials and methods: Commercially pure titanium and Ti-6Al-4V substrate metals were coated with hydroxyapatite by plasma spray in plasma gas atmospheres of argon, argon/ hydrogen, nitrogen, and nitrogen/hydrogen. The microstructure and interfacial bonding between the metal substrate and HA coating were studied by scanning electron microscopy, energy dispensive X-ray analysis (EDAX), and X-ray diffraction. Results: The analyses of the coatings obtained showed a different microstructural pattern of HA and diffusion of elements across the interface of metal and HA coating and chemical bonding for all plasma gas atmospheres. Conclusion: The plasma-coating atmosphere influences the microstructure and crystallization of HA. Diffusion of elements from metal substrate to HA coating and coating to metal surface indicate chemical bonding between the metal and coating in addition to usual mechanical bonding. Clinical significance: Bonding between the metal substrate and HA coating play a significant role in the stability of the dental implant. In addition to mechanical bonding, the plasma coated implants show some amount of chemical bonding at the interface. © 2018, Jaypee Brothers Medical Publishers (P) Ltd. All rights reserved.Item Effect of simulated heating of plasma coating and ceramic firing on Ti and Ti-6Al-4V(Elsevier Editora Ltda, 2019) Kotian, R.; Rao, P.P.; Bangera, M.K.; Madhyastha, P.; Srikant, S.The study was performed to understand the impact of heat in plasma coating and ceramic firing of titanium (Ti) and titanium alloy (Ti-6Al-4V) on their mechanical properties, and microstructure. Standard specimens were prepared to measure tensile strength before and after simulated heating cycles using Instron machine of model 4206 at a crosshead speed of 1â»mm/min. Yield strength, ultimate strength, and elongation were recorded. The microstructure was studied using an optical microscope. The mechanical properties, microstructure, and grain size remained the same as that of as-received samples at temperatures of 600 and 700â»°C for both Ti and Ti-6Al-4V. At temperature 800 and 900â»°C decrease in yield strength, and ultimate tensile strength with a change in microstructure was observed. The temperature of plasma coating and ceramic firing that Ti and Ti-6Al-4V metal substrates encounter during the fabrication of coated implants and metal-ceramic restorations do not affect the mechanical properties and microstructure. Above 800â»°C, a significant change in mechanical properties and microstructure is observed. © 2019 The Authors.