3D full field strain analysis of polymerization shrinkage in a dental composite

ObjectiveThe objective of this research was to study the polymerization shrinkage in a dental composite using 3D digital image correlation (DIC).MethodsUsing 2 coupled cameras, digital images were taken of bar-shaped composite (Premise Universal Composite; Kerr) specimens before light curing and after for 10 min. Three-dimensional DIC was used to assess in-plane and out-of-plane deformations associated with polymerization shrinkage.ResultsThe results show the polymerization shrinkage to be highly variable with the peak values occurring 0.6–0.8 mm away from the surface. Volumetric shrinkage began to significantly decrease at 3.2 mm from the specimen surface and reached a minimum at 4 mm within the composite. Approximately 25–30% of the strain registered at 5 min occurred after light-activation. Application of 3D DIC dental applications can be performed without the need for assumptions on the deformation field.SignificanceUnderstanding the local deformations and strain fields from the initial polymerization shrinkage can lead to a better understanding of the composite material and interaction with surrounding tooth structure, aiding in their further development and clinical prognosis.