Australian Dental Council (ADC) Practice Test

Marginal leakage at the proximal gingival cavosurface of a recently restored Class II preparation is often caused by insufficient condensation of the restorative material. When a dental material, such as composite resin or amalgam, is not properly condensed, it fails to achieve optimal adaptation to the cavity walls. This can result in voids or gaps at the interface between the restoration and the tooth structure. These microscopic spaces allow fluids and bacteria to infiltrate, leading to potential marginal leakage.

Proper condensation is crucial because it not only aids in achieving close contact between the restoration and the tooth but also enhances the material's mechanical properties, which are vital for durability and longevity of the restoration. A well-condensed material minimizes the chances of marginal breakdown over time.

While the other factors, such as excessive moisture control, inadequate tooth preparation, and improper material choice, can also influence the overall success of a restoration, they are less directly linked to the specific issue of marginal leakage at the gingival cavosurface when comparing them to condensation techniques. Excessive moisture control typically refers to over-drying the tooth structure, which may hinder bonding but doesn't specifically cause marginal leakage in the same direct manner. Inadequate tooth preparation may lead to other complications, but if the preparation is within