Retention strength between veneering resin composites and laser-sintered cobalt–chromium alloy

Abstract

The purpose of the present study was to evaluate the retention strength between a resin composite veneering material and three types of cobalt-chromium (Co-Cr) alloy substrates. Co-Cr alloy specimens with 81 retention devices (LSR), with 144 retention devices (LDR), and without retention device (LN) were fabricated using a laser-sintering system. The specimens were air-abraded with alumina, conditioned with a primer [Alloy primer (AP) or M.L. primer (ML)], and veneered with a light-polymerized resin composite (Gradia). Three control groups (LSR-N, LDR-N, and LN-N) without primer were also prepared. After 20,000 thermocycles in 4 and 60 °C water, tensile retention strengths were determined using a universal testing machine. Data were analyzed by analysis of variance and a post hoc Tukey-Kramer HSD test (α = 0.05, n = 8). The highest retention strengths were obtained in LSR-AP (28.3 MPa), LSR-ML (23.3 MPa), LDR-AP (26.9 MPa), and LDR-ML (27.8 MPa), and these values were not significantly different. In the absence of a retention device, the retention strengths were significantly different in the following order: LN-N (0.1 MPa) < LN-ML (12.4 MPa) < LN-AP (20.2 MPa). The specimens without primer were significantly different in the following order: LN-N (0.1 MPa) < LSR-N (15.4 MPa), LDR-N (17.1 MPa). No significant difference was found between the numbers of retention devices, which were 81 and 144. In conclusion, the combined use of the primers and the retention devices is recommended when the laser-sintered Co-Cr alloy is veneered with the resin composite materials to maximize the retention strength.

Aspects and Principles of Material Connections in Restorative Dentistry—A Comprehensive Review

“…This is performed at the stage of the preparation of the wax element, the surface of which is sprinkled with retentive wax beads. After replacing the wax with metal, the obtained retention elements increase the bond strength of the composite to the cobalt chrome alloy as much as two-fold [ 68 ].…”

New generation CAD-CAM materials for implant-supported definitive frameworks fabricated by using subtractive technologies

“…Co-Cr frameworks can be veneered with polymethyl methacrylate (PMMA) [ 22 , 31 ], composite resin [ 32 ], or porcelain [ 15 , 23 , 33 , 34 ]. Li et al [ 16 ] indicated that soft-milled Co-Cr had superior strength after repeated porcelain firings when compared with hard-milled or cast Co-Cr.…”