IADR Abstract Archives
Bond strength of precious alloy to base metal
Double crown technique is commonly used treatment modality in removable prosthodontics. In order to achieve a passive denture-abutments fit, it is advocated to cement secondary crowns to base-metal framework. In this in vitro experiment bond strengths of gold cylinders to Co-Cr alloy were studied and the influence of elevated temperature and pressure was evaluated.
Method:
90 disc-shaped specimens (10x3mm) were cast from Co-Cr alloy and the corresponding cylinders (4x4mm) were fabricated from a high-gold-content alloy. Bonding surfaces were polished and airborne-particle abraded (110μm Al2O3). Gold cylinders were bonded to base metal using 3 different resin-based cements (Nimetic Cem, 3M ESPE, USA: NC; AGC Cem, Wieland, Germany: AGC; Multilink, Ivoclar, Liechtenstein: ML) and exposed to the following experimental conditions: control group, 60°C-6Bar-20min, 100°C-6Bar-35min. Load to failure was measured and the bond strength calculated. The data were statistically analyzed (ANOVA, Tukey’s, p<0.05). Failure modes were determined by optical microscope.
Results:
Bond strength of precious alloy to base metal (MPa) |
|||
|
NC |
AGC |
ML |
control group |
17.81 ± 5.59 |
16.75 ± 3.42 |
28.94 ± 5.85 * |
60°C-6Bar-20min |
15.82 ± 3.78 |
17.18 ± 2.72 |
29.98 ± 4.60 * |
100°C-6Bar-35min |
14.54 ± 2.78 |
17.63 ± 3.02 |
29.36 ± 3.65 * |
Different temperature and pressure conditions did not significantly affect the bond strength. Bond strengths obtained with ML were significantly higher (* p<0.05) compared with NC and AGC and these groups showed combination failures.
Conclusion:
Within the limitations of this in vitro study, it can be concluded that temperature and pressure do not influence the bond strength of precious alloy to base metal. Selection of adhesive resin is important.