Australian Dental Council (ADC) Practice Test 2026 - Free ADC Practice Questions and Study Guide

The optimum cavosurface angle for an occlusal amalgam surface is typically in the range of 95-110 degrees. This angle is crucial for ensuring sufficient mechanical retention and providing an adequate seal to prevent microleakage, which can lead to secondary caries and restoration failure.

An angle within this range allows for a larger surface area of contact with the amalgam material, promoting better adaptation of the restorative material to the tooth structure. Such a design helps distribute occlusal forces more evenly across the restoration, minimizing the risk of fracture or dislodgment during function.

Additionally, maintaining a wider cavosurface angle aids in facilitating the condensation of the amalgam, ensuring that the material can be adequately packed into the preparation without voids. This is particularly important for achieving the mechanical properties desired in a durable, long-lasting amalgam restoration.

In contrast, angles that are too narrow may increase the risk of the amalgam being dislodged or may not allow sufficient space for the amalgam to bond effectively with the tooth structure. Therefore, the recommended angle is critical for maximizing the longevity and success of occlusal amalgam restorations.