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Aim and Objectives: In dentistry, base metal casting alloys are extensively used for the fabrication of inlays, onlays, crowns, bridges, partial dentures, etc. During the casting of these alloys, excess amount of material used than needed will be collected as sprue buttons at the end, which is either added to the fresh alloy during casting and reused or disposed of. Materials and Methods: The aim of the present in vitro experimental study was to investigate the effect of the complete recasting of four commercially available cobalt-chromium (Co-Cr) and nickel-chromium (Ni-Cr) base metal casting alloys on their cytotoxicity. During the study, four groups of alloys were subjected to complete recasting up to twenty times without the addition of new alloy. The cytotoxicity assessment of the selected alloys after recasting (Co-Cr and Ni-Cr alloys) was carried out using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Results: The results indicated that Co-Cr alloys exhibit superior cell viability compared to Ni-Cr alloys, and cytotoxic potential of the alloys increased with repeated casting and led to increased cell death. The recasting of alloys in the present study did not show high cytotoxicity even after the 20 th recasting. Conclusion: From the results of the present study, it can be concluded that the alloys generated as a waste in the dental laboratory can be safely reused up to five times or at least once before they can be disposed, which reduces the cost of the treatment and also helps in conserving the natural resources.

Aim:The aim of this study was to quantitatively estimate the concentration of ion release from recasted base metal alloys in various pH conditions using atomic absorption spectroscopy (AAS).Materials and Methods:Specimens of commercially available dental casting alloys (cobalt [Co]-chromium [Cr] and nickel [Ni]- chromium [Cr]) were prepared using lost-wax casting techniques and were stored in the test solution for 1 week and 4 weeks, and ions released during chemical corrosion were detected using AAS.Results:An increase in the quantity of ion release was observed with recasting. These changes were higher after twice recasting in Ni-Cr alloy.

Additive manufacturing (AM) is evolving continuously which enables 3D printing a given idea into a functional prototype, the complex structures can be 3D printed with versatility of changing the density depending on the in-fills programmed during printing thus it can be light in weight with less material wastage which cannot be achieved by other methods. Polyether ether ketone (PEEK) is widely used in implantable devices such as spinal, dental and orthopedic implants due to its superior biocompatibility and nearly matching properties with bone. Polyamide (PA) is another biomaterial widely used as sutures, catheters, and dentures due to its biocompatibility. In the present study, the specimen of PEEK and polyamide were 3D printed and the mechanical properties evaluated and compared for healthcare applications. Methodology: In this work, a comparison of mechanical strength such as compressive strength (CS), tensile strength (TS), flexure strength (FS), and impact strength (IS) of 3D printed PEEK samples by fused deposition modelling (FDM) and PA specimens by selective laser sintering (SLS), respectively. Samples for mechanical strength were prepared according to ASTM and ISO specifications. Result: The strength of the Polyether ether ketone was higher than that of Polyamide. Conclusions: The results of this experiment provide a comprehensive understanding of the mechanical strength of PEEK and PA, that can be used as a valuable guide for their healthcare applications.

Connecting Rod is a link between Piston and Crank. It is meant to transfer combustion forces from the Piston to Crank. In the present work an Aluminium based metal matrix composite is proposed as a material for Connecting Rod. Composition of the proposed material is Aluminium 6061-9%Silicon carbide-15% fly ash. Model of a Connecting Rod is designed and stress analysis is done using Finite Element Analysis. Proposed material is compared with an existing Connecting Rod material Aluminium-360. Parameters like von-misses stress, von-misses strain, deformation, factor of safety and weight reduction were calculated. From the comparison proposed material is found to be 26.11 % lesser weight, more stiffer by 7.21 %, shows improved factor of safety and can sustain higher stress.