Comparison of resistance features for complex amalgam restorations

Area of Science:

• Dental Materials Science
• Restorative Dentistry
• Biomaterials Engineering

Background:

• Complex amalgam restorations require adequate resistance to occlusal forces.
• Various retentive features are used to enhance the longevity of amalgam restorations.

Purpose of the Study:

• To evaluate and compare the resistance to failure of Dispersalloy amalgam restorations using different retentive features.
• To determine the effectiveness of pins, amalgapins, and peripheral shelves, individually and in combination, in reinforcing amalgam restorations.

Main Methods:

• Fifty extracted maxillary molar teeth were prepared and divided into five groups, each receiving a different resistance form configuration.
• Amalgam restorations were placed, standardized, and subjected to compressive loading at 45 degrees until failure.
• Failure loads were recorded, and statistical analysis (ANOVA and Tukey B) was performed.

Main Results:

• Groups utilizing pins (1), amalgapins (2), and amalgapins with a peripheral shelf (5) demonstrated comparable mean failure loads.
• A peripheral shelf alone (3) provided significantly less resistance compared to pin or amalgapin groups.
• Pins combined with a peripheral shelf (4) showed intermediate resistance, but not significantly different from the pin or amalgapin groups.

Conclusions:

• Pins and amalgapins offer comparable and robust resistance forms for complex amalgam restorations.
• The addition of a peripheral shelf to amalgapins further enhances, or at least maintains, restoration resistance.
• Peripheral shelves alone are insufficient for reinforcing complex amalgam restorations against occlusal forces.