COMPARISON OF BOND STRENGTHS OF 3 DENTURE BASE RESINS TO TREATED NICKEL-CHROMIUM-BERYLLIUM ALLOY

Purpose. In-vitro bond strengths of 3 denture base resins (Trutone, Lu citone 199, and Triad) to a nickel-chromium-beryllium removable partia l denture alloy (Ticonium) were tested with 3 surface pretreatments: s andblast, acid etch, and Rocatec (silica blasting), with Or without pr imers (Dentsply, CR inlay cement, and Super Bond). Material and method s. Lucitone 199 denture base resin bonded to the nonprimed sandblasted alloy specimen served as the control group. Alloy specimens were prep ared, surface treated, and primed or not primed with primer. The treat ed specimens were then packed and processed with the denture base resi n. Bonded specimens were stored in the distilled water at 37 degrees C for 24 hours, and then debonded in tension. The force at which the bo nd failed was noted, and bond strength was calculated in megapascals ( MPa). Fire replications for each condition (180 specimens total) were tested. Results. Significant differences in bond strength were observe d with primer, the most important factor, followed by pretreatment and denture base resin. Without primer for all 3 denture base resins, the Met-Etch and Rocatec treated groups showed significantly higher bond strengths than the sandblasted groups. For Trutone denture base resin, nonprimed treated groups produced significantly higher bond strength than those for the other 2 denture base resins. The control group had zero bond strength. For Dentsply primer, the Rocatec treated group bon ded to Lucitone 199 resin produced the highest bond strength value (14 .8 +/- 1.8 MPa). For CR inlay cement, the Met-Etch and Rocatec treated groups for Lucitone denture base resin demonstrated the highest bond strength (19.3 +/- 4.8 MPa, and 19.3 +/- 1.8 MPa, respectively). For S uper Bond primer, the Met-Etch treated group fur Trutone resin demonst rated the highest bond strength (19.8 +/- 6.2 MPa). Conclusions, Witho ut primer, the control had the lowest bond strength (0 MPa), and the T rutone groups showed the highest bond strength (11.7 +/- 4.1 MPa). Mrt -Etch and Rocatec treated groups produced higher bond strengths than t he sand blasted groups. The primed specimens demonstrated significantl y higher bond strengths than nonprimed specimens, except for Trutone r esin, for which primed specimens produced lower bond strengths than th e nonprimed specimens.