1292 Bond Strengths for Four Noble Alloys to Conventionally Layered Porcelain

Saturday, March 24, 2012: 9:45 a.m. - 11 a.m.
Presentation Type: Poster Session
A. KHMAJ1, M. KHMAJ1, W. BRANTLEY1, W. JOHNSTON1, T. DASGUPTA2, P. MCCABE2, and G. TYSOWSKY2, 1College of Dentistry, Division of Restorative and Prosthetic Dentistry, Ohio State University, Columbus, OH, 2Ivoclar Vivadent, Inc, Amherst, NY
Objective: Rational selection of an appropriate alloy for a metal-ceramic restoration requires knowledge of the bond strength to dental porcelain. The objective of this study was to evaluate the bond compatibility index (bond strength) of four recently introduced noble alloys, one high-gold alloy and three more economical alloys, bonded to a compatible porcelain, using the current ISO standard and conventional layering for the porcelain.

Method: (1) Aquarius Hard, a high-gold alloy (86.1Au-8.5Pt-2.6Pd-1.4In), (2) Evolution Lite, a reduced-gold alloy (40.3Au-39.3Pd-9.3In-9.2Ag-1.8Ga), (3) Callisto 75 Pd, a Pd-Ag-containing alloy (75.2Pd-2.5Au-7.1Ag-9.3Sn-1.0In), and (4) Aries, a conventional Pd-Ag alloy (63.7Pd-26.0Ag-7.0Sn-1.8Ga-1.5In) were selected for bonding to a leucite-containing veneering porcelain (IPS InLine). All products are marketed by Ivoclar Vivadent. Ten metal-ceramic specimens meeting the dimensional requirements for ISO 9693 were prepared for each alloy using recommended manufacturer techniques and the standard porcelain layering method used in dental laboratories. The three-point bending test in the ISO standard was performed to determine the bond strength. Values for the four alloys were compared using one-way ANOVA and the Tukey test (α = 0.05 for statistical significance). 

Result: Mean values with standard deviations for bond strength (MPa) were as follows: Aquarius Hard (50.7 ± 5.5; Evolution Lite (40.2 ± 3.3); Callisto 75 Pd (37.2 ± 3.8); Aries (34.0 ± 4.9). The mean bond strength observed for the high-gold alloy (Aquarius Hard) was significantly higher than the mean bond strength for the other three alloys. The lowest mean bond strengths for the Pd-Ag-containing alloy (Callisto 75 Pd) and the conventional Pd-Ag alloy (Aries) were not significantly different from each other. 

Conclusion: All four noble alloys had mean metal-ceramic bond strength that substantially exceeded the 25 MPa minimum in the ISO standard. Clinical selection of these alloys will depend upon other mechanical properties such as yield strength and modulus of elasticity. 

Keywords: Alloys, Physical, Porcelain systems, Prosthodontics and Stress