HOLOGRAPHIC INTERFEROMETRY AS A METHOD FOR MEASURING STRAIN CAUSED BY POLYMERIZATION SHRINKAGE OF DENTAL COMPOSITE

Abstract

Polymerization shrinkage is one of the most critical properties of esthetic resin-based dental restorative materials and may have a negative impact on their clinical performance. As the composite is adhesively bonded, contraction of composite material that occurs during the polymerization causes stress and strain of hard dental tissues. Polymerization shrinkage also affects the maintenance of the bonded interface between the composite resin and dental hard tissues. The aim of this study is to present holographic interferometry as a method for detecting and measuring strain of dental hard tissue caused by the polymerization shrinkage of the dental composite. Materials and methods: Strain was measured experimentally, by real time holographic interferometry, on the maxillary teeth. Strain of dental tissue was determined by counting the interferomentic fringes that appeared during the polymerization process. Results: The deformation was recorded on the coronal dental tissue from 2.25 μm to 5.8 μm. The conclusion is that holographic interferometry is a non-contact, non-destructive, very precise method for measuring deformation of hard dental tissues that is caused by the polymerization shrinkage of dental composite