Light Polymerization and Control of Shrinkage Stresses

This session highlights the challenges associated with the polymerization of resin-based materials and provides practical guidelines for achieving optimal irradiance. It addresses common myths and evidence-based facts regarding polymerization shrinkage and explores strategies to limit its effects, including the “elastic layer” concept (flowable liners), as well as the debated role of incremental layering and curing techniques. The lecture also reexamines the traditional emphasis on the C-factor (cavity configuration), introducing the more clinically relevant concept of the V-factor (volume of restorative material). A simple visual model the glass tube technique will be presented to help clinicians better understand and assess polymerization stresses. Finally, the session translates these concepts into clinical practice, showcasing effective stress-reduction strategies such as sandwich techniques, the use of prepolymerized inserts, and the placement of short fiber-reinforced composites.