Abstract
(1) To conduct a comprehensive review of the literature on factors influencing the radiant exposure of resin-based composite (RBC) restorations and (2) To fully understand the appropriate way of using the light curing units (LCUs) to perform restorations with optimal mechanical/physical properties.
A PubMed search identified recent publications in English that addressed the factors affecting the longevity of the RBC restorations and the optimal usage of LCUs.
RBCs require light-induced polymerization of methacrylate monomers present in its composition to reach acceptable mechanical and physical properties. Complete polymerization of the RBC is never reached, and the maximum degree of conversion (DC) varies from 40 to 80%. The amount of radiant exposure (Joules/cm²) required for the commencement of polymerization becomes a core driver for the quality of the RBCs. Insufficient radiant exposure may lead to low strength behavior and susceptibility to degradation, thereby shortening the lifespan of restorations inside the mouth. This suggests that there are factors affecting the radiant exposure during clinical procedures; these factors can be categorized as material-related, LCU-related and operator-related factors.
Proper light-curing techniques are critical for delivering an adequate amount of radiant exposure to RBCs. Adequate light curing decreases the number of underexposed RBC restorations, improves their mechanical and physical properties and accordingly, increases their clinical longevity.