Adhesion testing of a denture base resin with 5 casting alloys

Area of Science:

• Biomaterials Science
• Dental Materials Science
• Prosthodontics

Background:

• Hybrid implant prostheses utilize various alloys for framework fabrication.
• Denture base resin adhesion to these alloys is critical for prosthesis longevity.
• Understanding alloy-specific bond strengths and microleakage is essential for clinical success.

Purpose of the Study:

• To compare the shear bond strengths of denture base resin to silicoated gold-palladium (Au-Pd), gold-palladium-silver (Au-Pd-Ag), gold-silver-palladium-copper (Au-Ag-Pd-Cu), high-palladium (high-Pd), and nickel-chromium-beryllium (Ni-Cr-Be) alloys.
• To evaluate and compare microleakage between the alloy and resin interfaces after specimen fracture.

Main Methods:

• Cylindrical alloy specimens were cast, machined, abraded, and silicoated.
• Denture base resin was processed onto the internal surfaces of the silicoated specimens.
• Specimens underwent thermocycling and were tested for shear bond strength using a punch method.
• Microleakage was assessed by dye penetration and quantified using an optical microscope and grid system.

Main Results:

• Mean shear bond strengths for Au-Pd (9.6 MPa) and Au-Ag-Pd-Cu (9.2 MPa) alloys were significantly higher than for Au-Pd-Ag alloy (5.6 MPa).
• No significant differences in shear bond strength were found among Au-Pd, Au-Ag-Pd-Cu, high-Pd, and Ni-Cr-Be alloys.
• Dye penetration, indicating microleakage, showed no significant differences among the five alloy groups, averaging 25% of the bonded area.

Conclusions:

• Alloy composition significantly influences denture base resin shear bond strength to silicoated alloys.
• Au-Pd and Au-Ag-Pd-Cu alloys demonstrate superior bond strength compared to Au-Pd-Ag.
• All tested silicoated alloys exhibited comparable levels of microleakage under the study conditions.