Evaluation of ceramic adherence to cobalt-chromium alloys fabricated by different manufacturing techniques

Statement of problem. Selective laser melting has been increasingly used in the fabrication of metal-ceramic prostheses. The longevity of the prostheses depends on the strength of the metal-ceramic bond, which may differ with the framework manufacturing technique. Purpose. The purpose of this in vitro study was to compare the bond strength of ceramic to cobalt-chromium (Co-Cr) alloys fabricated by different manufacturing methods. Material and methods. Sixty circle divide 15x2-mm disk-shaped specimens were prepared and assigned to 3 groups (n=20) with different manufacturing methods: milled Co-Cr (M), selective laser melted Co-Cr (SLM), and cast Co-Cr (C). The disks were ceramic layered with a 2-mm thickness. Half of the specimens from each group were thermocycled. The shear bond strength (SBS) test was applied to all specimens. The microstructure changes after ceramic layering were evaluated by X-ray diffraction (XRD). The specimens' surface morphology was analyzed by using scanning electron microscopy (SEM). Results. Thermocycling had a significant effect on SBS values in the SLM group (P=.017). Considering the registered F-max (force inducing bonding failure), a significant difference was found between SLM and both M and C groups (P<.001). No significant difference was found between milled and cast Co-Cr (P=.885). The failure types were mostly mixed failures. Ceramic layering induced a crystallization increase in groups C and SLM. Conclusions. The adhesion strength of ceramic to Co-Cr differed with alloy composition and manufacturing technique. The aging process influenced the results in the SLM group.

Automated summary

The purpose of this study was to compare the bond strength of ceramic to cobalt-chromium (Co-Cr) alloys fabricated by different manufacturing methods. The results showed that the alloy composition and manufacturing technique influenced the adhesion strength of ceramic to Co-Cr.