Effect of Pretreatment Process on the Metal-Porcelain Bonding Mechanism and Properties of CoCr Alloy Dental Crown and Bridge Manufactured by SLM

This paper aims to investigate the influential mechanism of grinding and sand blasting pretreatment of CoCr alloy manufactured by SLM (selective laser melting) process on the metal-porcelain bonding of the restorations, and then provides references for SLM manufacturing CoCr alloy dental crown and bridge restorations with good mechanical properties. Three groups of CoCr alloy substrates were manufactured by SLM process with optimal parameters. The samples were subjected to different grinding and sand blasting pretreatment, and the porcelain sintering was carried out with the same parameters. The samples of different groups were analyzed by three-point bending test, roughness test, SEM and EDS. Results show that the metal-porcelain bonding strength of samples in group a with grinding and sand blasting is 36.79±0.49 MPa, which is obviously higher than those of group b with no grinding but sand blasting and group c with only grinding. The average metal-porcelain bonding strength of the three group samples is higher than the ISO9693: 1999 standard minimum 25 MPa. The metal-porcelain bonding effect of group a and c is better than that of group b, and the element diffusion on metal-porcelain interface is observed in all three groups. The results also show that there are significant differences among the three groups on residues and element distribution of metal-porcelain peeling surface. The final conclusion is that the surface roughness obtained by the pretreatment of sand blasting and grinding can ensure the strong chemical combination of metal and porcelain and considerable mechanical properties combination, which can improve the performance of metal-porcelain restorations manufactured by SLM.