A. Siddharthan

Synthesis and characterization of nanocrystalline apatites from eggshells at different Ca/P ratios.

Nanocrystalline apatites with different Ca/P ratios were synthesized using eggshell as a calcium source by microwave processing. The apatites were found to have a minor amount of Mg, Sr, Si and Na ions inherited from the eggshells. The presence of several foreign ions results in a perturbed lattice structure indicated by an increase in lattice constants and shift in vibrational frequencies of the functional groups. The apatites were heat treated to investigate the influence of foreign ions on thermal stability. The minor amounts of ions do not affect the thermal stability. The differences in thermal behaviour of these apatites were due to the presence of HPO(2-)(4) ions only and not due to other ions because of their low content.

Eggshell-Derived Hydroxyapatite: A New Era in Bone Regeneration.

Background:Defects of maxillofacial skeleton lead to personal (functional and aesthetic), social and behavioral problems; which make the person to isolate from the main stream of society. So, bone regeneration is the need for proper structure, function, and aesthetics following cyst enucleation, trauma, and tumor ablative surgery; which helps for overall health of the individual. Aim and Objectives:The preliminary study is planned to evaluate and compare the efficacy of eggshell-derived hydroxyapatite (EHA) and synthetic hydroxyapatite (SHA) following cystectomy. Material and Methods:Microwave-processed calcium deficient EHA and commercially available SHA are used for grafting. Total 20 patients enrolled in this study, consisting 10 in each group between 20 and 45 years of age. All the patients were evaluated for bone regeneration at first, second, third, and sixth months interval, postsurgically, using radiovisiograph and clinical parameters. Results:The bone formation characteristics vary at second month when compared to SHA. This difference may be because of the kinetics involved in the regeneration pattern. The pattern of bone healing was trabecular after third month, indicating complete bone formation. The study showed constant raise of density and remained same at the end of study period. Conclusions:Both EHA and SHA graft materials are equally efficient in early bone regeneration. Within the limitations of this study the EHA showed promising results. Which indicates the eggshell waste-bio mineral is worthwhile raw material for the production of HA and is a Go Green procedure. Eggshell-derived hydroxyapatite is economic, compared with SHA.

Bioceramics coating on Ti-6Al-4V alloy by microwave processing

Abstract A novel method of hydroxyapatite (HA) coating on Ti–6Al–4V alloy by microwave (MW) processing has been developed to form an adherent coating within ∼25 min. The X-ray diffraction pattern of the coated sample shows the presence of HA and titanium oxides. Scanning electron micrograph indicates that the thickness of the coating is to be ∼150 μm with a good interface with the alloy. The compositional analysis using energy dispersive X-ray spectroscopy also confirms the formation of a composite coating of apatite and titanium oxides. The MW active nature of the non-stoichiometric titanium oxides seems to influence the bonding of HA with the titanium oxide grown on the alloy surface. The presence of the Widmanstätten structure of the substrate as observed by optical microscopy indicates that the process temperature of the coating may be above β transus temperature of the alloy. The alloy substrate also shows an increase in the hardness and Young’s modulus which may be due to diffusion of oxygen and/or nitrogen during the coating process into the alloy.