Metal-porcelain Bond Strength Of Co-Cr Alloy Processed By Selective Laser Melting

PFM has the advantages of real color and strength which is widely used in restoration of teeth destroyed and teeth incomplete.There are some drawbacks in the traditional casting method,such as the long process flow and more defects.In recent years,SLM technology has been gradually applied in oral field.Due to the special working principle,the process of PFM can be effectively improved.This paper is focus on the suitability of making PFM based on SLM technology.Deep research is carried out around the influence of the bond strength between metal and porcelain by sand blasting and preoxidation.The main work and research are as follows:(1)Through the SLM technology to produce the Co-Cr base crown,the crown is used to match with plaster model.In addition,the standard specimens is processed to the important mechanical properties.The results showed that the precision and the mechanical properties of the Co-Cr base crown can meet the clinical requirements by SLM technology.(2)Co-Cr alloy specimens were made by SLM technology according to the YY0621-2008 standard.The surface state of different roughness were obtained by sand blasting.After preoxidition treatment,the bond strength of porcelain fused to metal was tested.The result showed the bond strength between Co-Cr alloy and porcelain treated by 100 mesh and 120 mesh Al2O3 is higher than that of the non sand blasting group and the 80 mesh group.It is proved that sand blasting is beneficial to the bond strength of SLM Co-Cr alloy.(3)By preoxidation treatment of SLM Co-Cr alloy specimens at different times,then the surface morphology and elemental migration of metal ceramic were observed by scanning electron microscope.The bond strength of porcelain fused to metal was detected by t hree point bending test after porcelain fused to metal.It was concluded that the best pretreatment time was 60 s.(4)The conventional preoxidation treatment of Co-Cr specimens was carried out on the cast group,and the bonding strength was detected by three point bending test,after the porcelain fused to metal.Finally,the SLM technology and casting technology can get the similar Co-Cr alloy porcelain bonding strength,are higher than the YY0621-2008 standard 25 MPa.