What reduces marginal leakage associated with polymerization shrinkage in restorations?

A thin luting layer significantly reduces marginal leakage associated with polymerization shrinkage in restorations. When a thin layer of luting material is employed, it allows for a more intimate contact between the restoration and the tooth structure. This close contact helps to minimize the gap that may occur due to shrinkage during the curing of the material.

Marginal leakage can lead to post-operative sensitivity, secondary caries, and restoration failure. By optimizing the thickness of the luting layer, the risk of such issues is mitigated, allowing for better adaptation and sealing at the margins.

In contrast, low viscosity materials might not necessarily address shrinkage effectively; they could flow too easily and fail to maintain a stable bond as they cure. The characteristics of porcelain, such as low corrosion features, pertain more to the material's durability and longevity rather than directly addressing marginal leakage due to polymerization. Lastly, while a high thermal expansion coefficient can have implications for fit and adaptation, it primarily influences how materials respond to temperature changes rather than directly impacting the effects of shrinkage during polymerization. Thus, utilizing a thin luting layer is the most effective strategy to reduce this type of leakage.