Annelies Van Ende1, Elke Van de Casteele2, Maarten Depypere3, Jan De Munck1, Xin Li1, Frederik Maes3, Martine Wevers4, Bart Van Meerbeek5. 1. KU Leuven - BIOMAT, Department of Oral Health Sciences, KU Leuven (University of Leuven) & Dentistry, University Hospitals Leuven, Leuven, Belgium. 2. KU Leuven - BIOMAT, Department of Oral Health Sciences, KU Leuven (University of Leuven) & Dentistry, University Hospitals Leuven, Leuven, Belgium; Department of Materials Engineering, KU Leuven (University of Leuven), Leuven, Belgium. 3. ESAT - PSI, iMINDS - MIC Medical Image Computing, KU Leuven (University of Leuven), Leuven, Belgium. 4. Department of Materials Engineering, KU Leuven (University of Leuven), Leuven, Belgium. 5. KU Leuven - BIOMAT, Department of Oral Health Sciences, KU Leuven (University of Leuven) & Dentistry, University Hospitals Leuven, Leuven, Belgium. Electronic address: bart.vanmeerbeek@med.kuleuven.be.
Abstract
OBJECTIVE: The present study aimed at a better understanding of the internal shrinkage patterns within different cavity sizes. METHODS: Ten 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. RESULTS: 3D 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 2mm 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. SIGNIFICANCE: Polymerization-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.
OBJECTIVE: The present study aimed at a better understanding of the internal shrinkage patterns within different cavity sizes. METHODS: Ten 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. RESULTS: 3D 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 2mm 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. SIGNIFICANCE: Polymerization-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.
Authors: Larissa Marinho Azevedo; Leslie Carol Casas-Apayco; Carlos Andres Villavicencio Espinoza; Linda Wang; Maria Fidela de Lima Navarro; Maria Teresa Atta Journal: J Appl Oral Sci Date: 2015 May-Jun Impact factor: 2.698
Authors: Thomas De Schryver; Manuel Dierick; Marjolein Heyndrickx; Jeroen Van Stappen; Marijn A Boone; Luc Van Hoorebeke; Matthieu N Boone Journal: Sci Rep Date: 2018-05-16 Impact factor: 4.379