Wear of a Bioceramic Dental Restorative Material by Tooth Brushing

Abstract

To study the wear from tooth brushing of a new bioceramic dental restorative material, a toothbrush test has been conducted. The bioceramic is composed of calcium aluminate hydrate as binder and dental glass as filler. The material is intended to be used in small and medium sized posterior class I, II and V fillings. Twenty years of tooth brushing was simulated in an accelerated wear test with an exchange of the brushes every half-year. During testing, the brushes were covered with a mixture of artificial saliva and toothpaste. The volumetric wear was measured in a stereomicroscope and a profilometer was used to measure the changes in surface roughness. For comparison a glass-ionomer cement and a polymer composite were also tested. The worn surfaces were studied using scanning electron microscopy. Two different wear regimes could be detected on the samples, severe wear at the corners and mild wear at the top. The bioceramic had less severe wear than the composite and about the same as the glass-ionomer cement but the steady state wear rates were similar. The surface roughness (the mild wear) of the bioceramic was lower than that of the glass-ionomer and higher than that of the composite. The difference in surface roughness could be related to the microstructure (particle size and distribution) of the materials.