The ability to bond acrylic to chrome/cobalt removable partial denture frameworks influences the ability to repair these prosthesis. A number of products currently claim to bond acrylic to chrome/cobalt. Objectives: This study is to determine the effect of air abrading the metal framework prior to placement of acrylic on the bond strength of two products metal/acrylic bonding agents; GC Metal Primer II (GC America, Inc. Alsip, IL)(GC) and C&B Metabond (Parkell, Farmingdale, NY)(C&B) Methods: Twelve 25mmx25mm flat/polished Vitalium (Dentsply-Austenal, York, PA) plates were fabricated. One half of each of the plates were thoroughly etched with 50 micron aluminum oxide (90 psi). The surface of each plate received one of three treatments, none, GC or C&B making six groups air abraded (A), no surface treatment (C), GC abraded (GCA), GC non-abraded (GCN), C&B abraded (C&BA) and C&B non-abraded (C&BN). 5.5mm diameter columns of acrylic (Pour-N-Cure, GC America) were placed on the metal surface and cured as per instructions. Excess acrylic was carefully removed under magnification with a scalpel. Resin columns were subjected to a shear force utilizing an Instron 1123 (Canton MA) at 0.5mm/min crosshead speed. Mean value at failure (+ se) was calculated and ANOVA with Scheffe post-hoc performed to determine significance. Results: Mean shear failure (±se) was 4.5 (±0.4), 0.4 (±0.3), 10.2 (±0.8), 3.1 (±0.3), 15.2 (±0.5) and 0.3 (±0.3) MPa for A, C, GCA, GCN, C&BA and C&BN respectively. A was significantly stronger than any of the non-abraded specimens (p<0.001), C&BA were stronger than all 5 other groups (P<0.001) and GCA was stronger than the remaining 4 groups (p<0.001). Conclusions: Air abrasion alone significantly improves the bond strength of acrylic to metal. GC and C&B both require air abrasion doubling and tripling the bond strength (respectively). Air abrasion is necessary whenever bonding acrylic to metal.

Back to the Dental Materials: VI - Polymer Materials-Mechanical Properties and Degradation Program
Back to the IADR/AADR/CADR 82nd General Session (March 10-13, 2004)

Top Level Search