What is the typical percent of polymerization shrinkage in composite materials?

The typical percent of polymerization shrinkage in composite materials is generally in the range of 2 to 7%. This is an important characteristic of dental composites, especially considering how shrinkage can impact the bond strength and integrity of the restoration over time. When the composite material cures, it undergoes a chemical reaction that results in volumetric shrinkage; thus, understanding this percentage provides insight into clinical considerations, such as potential gaps between the filling and the tooth structure, which could lead to microleakage and subsequent caries.

Choosing a range of 2 to 7% reflects the commonly observed shrinkage levels in many dental composites used today, and it suggests that while some composites may exhibit lower shrinkage, others might push toward the upper limit of this range, depending on their formulation and constituent materials. This knowledge is essential for clinicians when selecting materials for dental restorations, as it affects the longevity and performance of the restoration.