Mechanical properties and microstructure of removable partial denture clasps manufactured using selective laser melting
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2015 Elsevier B.V. This study compares the mechanical response and microstructure of Co-Cr-Mo removable partial denture models made through conventional lost-wax casting and the selective laser melting additive manufacturing process. Co-Cr-Mo clasps for removal partial dentures, based on a wax model (BEGO USA), were fabricated through lost-wax technique and selective laser melting, and subjected to mechanical bending experiments to determine their yield strength and maximum reversible deformation. Single-Factor Analysis of Variance (ANOVA) was used to compare data from the two populations. Microstructure and chemical composition of the clasps were determined through scanning electron microscopy and wave-dispersive spectroscopy to rationalize the differences and similarities in the mechanical testing results from the two groups. It was found that the clasps made using lost-wax technique and selective laser melting exhibit comparable mean yield strengths and maximum elastic deformations, however the underlying microstructure of the cast clasps vastly differs from the laser-melted counterparts. Furthermore, the laser melted clasps exhibit larger variability in their mechanical response. While selective laser melting is capable of producing removable partial denture clasps with similar average mechanical responses to those of lost-wax cast counterparts, additional studies should be conducted to minimize the variability in the laser melted clasps in order to minimize unexpected failures.