Evaluation of bond strength of porous cobalt-chromium metal and pressed ceramic fabricated by additive manufacturing

Abstract

Statement of problem. A high metal-ceramic bond strength is important for successful dental restorations. However, studies on the evaluation of the bond strength of porous metal-ceramic restorations compared with conventional ones are scarce. Purpose. The purpose of this in vitro study was to compare the bond strength of a porous metaleceramic structure with conventional metal-ceramic restorations. Material and methods. Ten porous specimens were fabricated by selective laser sintering (SLS) according to the International Organization for Standardization 9693-1:2012, 10 specimens without porosity by SLS, and 10 cobalt-chromium (Co-Cr) cast specimens without porosity. The ceramic was applied with the pressing method. A 3-point bend test was performed with a universal testing machine, and the data were statistically analyzed by using 1-way analysis of variance (alpha=.05). Results. The mean +/- standard deviation bond strength of the porous group fabricated by SLS was the lowest (35.6 +/- 9.1 MPa), that of the group without porosity in the casting method was 43.5 +/- 7.8 MPa, and that of the group without porosity fabricated by SLS was the highest (47.7 +/- 4.5 MPa); these were statistically similar (P=.058). Conclusions. Although the porous structure reported the lowest bond strength among the 3 sets of test specimens, its bond strength was higher than the International Standards Organization standard of 25 MPa.