Effect Of Different Sandblasting Condition On The Metal-ceramic Bonding Strength Of Co-Cr Alloy Fabricated By Selective Laser Melting Technology

Objective: To investigate the effect of different sandblasting condition on the metal-ceramic bonding strength of Co-Cr alloy fabricated by selective laser melting technology,provide suitable surface treatment for Co-Cr alloy fabricated by selective laser melting technologyMethod : 1.Making specimens of Co-Cr alloy fabricated by SLM: Putting the bego Co-Cr alloy powder into the selective laser melting equipment in order to prepare 10mm×10mm×2mm 54 specimens, randomly divided into 9 groups, six specimens in each group. 2.Groups: According to the different sandblasting power sizes(A1=50um,A2= 100 um,A3= 150um) and the different sandblasting pressure(B1=0.2MPa,B2= 0.4MPa, B3= 0.6MPa), to form 9 groups like A1B1, A1B2, A1B3, A2B1, A2B2, A2B3, A3B1, A3B2, A3B3. Sandblasting processing method: specimens in each group were treated with corresponding particle size and pressure, at glancing angles of 45 degrees and a distance of 10 mm for 30 seconds. After the process, the specimens were washed in distilled water for 10 minutes, cleaned with steam under high pressure for 30 seconds, dried at room temperature for 24 hours. 3.Experimetal determination: One sample of each group was selected for observing microstructure by scanning electron microscope. The remaining groups of specimens were processed in steps recommended by the VITA porcelain powder manufacturers. Two layers of opaque ceramic were applied with a thin brush in the in the middle part of SLM specimen. The thickness of the opaque layer was in 0.1mm. The dentin porcelain was fired onto the specimens, until the formation of an cylindrical porcelain with diameter of 4 mm and height of 2 mm. Under the control of the homemade mould,45 shear bond test pieces were made using self-curing plastic. Using the electronic universal testing machine measured the force, then calculated the metal-ceramic bonding strength according to the formula.each interface failure modes of the specimens were observed.The results were statistically analyzed with spss 17.0 software.Result: 1. Analyzed the value of the shear bond strength test on different sandblasting conditions by two factors factorial analysis, the result shows: The shear bond strength among different sandblasting particle size presented significant statistical(P<0.05).The shear bond strength among different sandblasting pressure presented significant statistical(P<0.05).There was interaction between the factor“particle size”and the factor“pressure”(P<0.05). 2.Analyzed the value of shear bond strength test on different sandblasting conditions by One way ANOVA and compared each two groups by LSD test or Dunnett test. To particle for the analysis factor: when the sandblasting pressure was 0.2MPa, three different sandblasting size showed significant difference(P<0.05). When the sandblasting pressure was 0.4MPa, the value of SBS both group A2 and A3 were more than group A1, and only the group A1 and group A2 showed significant difference(P<0.05);when the sandblasting pressure was 0.6MPa,three different sandblasting size showed no significant difference(P>0.05). To pressure for the analysis factor: when the sandblasting particle size was 50 um or 150 um, three different sandblasting pressure showed no significant difference(P>0.05). When the sandblasting particle size was100 um, the value of SBS both group B2 was more than group B1 and group B3, and the group B1 and group B3 showed no significant difference(P>0.05). 3. After the shear strength test, all specimens fracture mode was mixed.Conclusion: 1.Metal-ceramic bonding strength was the maximum when specimens were sandblasted with 100 um alumina at 0.4 MPa pressure in this study. 2.when the specimens were sandblasted under 0.2MPa in this study, the metal-ceramic bonding strength was increased with the increase of the particle size.