Mechanical properties, corrosion resistance, and anti-adherence characterization of pure titanium fabricated by casting, milling, and selective laser melting

Milling and selective laser melting (SLM) technology have become new options for removable partial denture (RPD) processing. However, whether milling and SLM technology has an impact on the properties of RPD remains unclear, which is also the aim of our study. To investigate the effects of milling and SLM technology on pure titanium, mechanical property, corrosion resistance, and anti-adherence of specimens were evaluated, and specimens processed by lost-wax casting were used as control. Compared with casting and milling groups, the SLM group showed enhanced Vickers hardness (402.1 +/- 13.0 HV), tensile stress (694.4 +/- 4.5 MPa), and larger electrochemical capacitance arc radius compared with casting and milling groups. A series of adhesion-related genes (Als1, Als3, and HWP1) of Candida albicans cultured on SLM specimens were upregulated for more than two times that of casting and milling groups. However, images from scanning electron microscopy and confocal laser scanning microscopy exhibited similar biofilm morphology and biomass of C. albicans on a titanium disk processed by casting, milling, and SLM. Dwindled water contact angle (64.7 +/- 0.6 degrees) and higher TiO2 constituents (40.82%) in the SLM group might lead to the incompatibility of genetic expression and biofilm generation. Our findings indicated that SLM is an ideal process to produce titanium dentures, providing a reference on the selection of processing technology for dentists.