Research on the Role of Surface Treatment of the Metal Surface on the Strength of the Metal-Ceramic Bond.

AIM: The aim of the present study is to investigate the metal-ceramic bond strength as a result of three different surface treatment methods: (1) oxidation, (2) oxidation and sandblasting, and (3) double oxidation on the metal substrate.

MATERIALS AND METHODS: A total of 72 metal substrates were made from two different types of metal-ceramic alloys ( n = 36): group I, Ni-Cr and group II, Co-Cr alloys. Each group was further divided and subjected to three different surface treatments ( n = 12): (1) oxidation in accordance with the manufacturer's instructions; (2) oxidation according to the manufacturer's instructions and then sandblasting with Al2O3, with a grain size of 110 μm, a pressure of 75 psi for 10 sec with a distance of 5 cm and steam cleaning; and (3) double oxidation. The bond strength of the specimens was evaluated with the three-point bending process. The data were recorded, tabulated, and statistically analyzed.

RESULTS: For group I, the materials with oxidation based on the specifications, show mean value of 64.02 Nt. The oxidation and sandblasting materials have mean 55.92 Nt. The double oxidation materials have mean 55.47. For group II, the materials with oxidation based on the specifications, show mean value of 58.46 Nt. The oxidation and sandblasting materials have a mean value of 42.56 Nt. The double oxidation materials have mean 42.96 Nt.

CONCLUSION: The best method of treatment of the metal substrate is specification oxidation, in terms of the strength of the metal-ceramic bond. Further treatment of the metal substrate reduces the strength of the metal-ceramic bond.

CLINICAL SIGNIFICANCE: A prerequisite for clinical success of metal-ceramic prosthetic restorations is the increased strength of the bond between ceramic material and metal substrate. With that in mind, the present research gives important insight into best practices for prosthetic restorations.