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Surface treatment effects on amalgam repair strength
K E Diefenderfer1, J W Reinhardt, S B Brown
1Naval Dental Research Institute, Naval Dental School, National Naval Dental Center, Bethesda, MD 20889-5602, USA.
American Journal of Dentistry
|February 1, 1997
Summary
Microetching and bonding agents do not improve the shear bond strength of repaired dental amalgam. Simple carbide bur treatment provided the best results for amalgam repair, with adhesives sometimes weakening the bond.
Area of Science:
- Dental Materials Science
- Restorative Dentistry
Background:
- Dental amalgam restorations can degrade over time, necessitating repair.
- Effective repair techniques are crucial for extending the longevity of amalgam restorations.
Purpose of the Study:
- To evaluate the efficacy of microetching and bonding agents in enhancing the shear bond strength between aged and new dental amalgam.
- To simulate and optimize dental amalgam repair procedures.
Main Methods:
- Aged amalgam surfaces were prepared using a carbide bur, with or without microetching (Al2O3 abrasive).
- Five commercial adhesive systems were applied, followed by condensation of fresh amalgam.
- Shear bond strength was tested after storage and thermocycling, with control groups for comparison.
Main Results:
- The highest mean shear bond strength (25.8 MPa) was achieved with carbide bur treatment alone.
- Neither microetching nor the use of adhesive agents significantly improved amalgam-to-amalgam bond strength.
- Adhesive agents occasionally resulted in a significant decrease in the shear bond strength of repaired samples.
Conclusions:
- Surface preparation with a carbide bur alone is sufficient for achieving optimal shear bond strength in dental amalgam repairs.
- Microetching and the use of bonding agents do not enhance, and may even compromise, the bond strength in dental amalgam repair.
- Current adhesive systems may not be effective for improving the bond between aged and freshly added dental amalgam.