| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 1420580 | Dental Materials | 2015 | 9 Pages |
ObjectiveThe present study aimed at a better understanding of the internal shrinkage patterns within different cavity sizes.MethodsTen cylindrical cavities in two sizes were filled with a flowable composite and scanned using X-ray micro-computed tomography (μ-CT) before filling, before and after polymerization. Three-dimensional (3D) non-rigid image registration was applied to sets of two subsequent μ-CT images, before and after polymerization in order to calculate the displacements and strains caused by polymerization shrinkage.Results3D volumetric displacement analysis disclosed a main vertical component for both the small and large cavities, however in the latter the downward direction reversed to an upward direction from a depth of approximately 2 mm due to debonding at the bottom. Air bubbles and voids in the restorations increased upon polymerization, causing a reverse in strain in the surrounding areas.SignificancePolymerization-induced shrinkage stress in composite restorations cannot be measured directly. This exploratory study revealed more information on cavity-size dependent shrinkage patterns and opens the way to more extensive studies using different composite materials and varying geometric cavity configurations.
