Metal-ceramic bond strength of Co-Cr alloy fabricated by selective laser melting

This study was to evaluated the metal-ceramic bond strength of a Co-Cr dental alloy prepared using a selective laser melting (SLM) technique.

Two groups comprised of twenty Co-Cr metal bars each were prepared using either a SLM or traditional lost-wax casting method. Ten bars from each group were moulded into standard ISO 9693:1999 dimensions of 25 mm × 3 mm × 0.5 mm with 1.1 mm of porcelain fused onto an 8 mm × 3 mm rectangular area in the centre of each bar. Metal-ceramic bonding was assessed using a three-point bending test. Fracture mode analysis and area fraction of adherence porcelain (AFAP) were determined by measuring Si content of specimens by SEM/EDS.

Student's t-test within the groups demonstrated no significant difference for the mean bond strength between the SLM and traditional cast sample groups. While SEM/EDS analysis indicated a mixed fracture mode on the debonding interface of both the SLM and the cast groups, the SLM group showed significantly more porcelain adherence than the control group (p<0.05).

The SLM metal-ceramic system exhibited a bonding strength that exceeds the requirement of ISO 9691:1999(E) and it even showed a better behaviour in porcelain adherence test comparable to traditional cast methods.