Resistance of nanofill and nanohybrid resin composites to toothbrush abrasion with calcium carbonate slurry

The aim of this study was to investigate the wear of four nanofilled resin composites using simulated toothbrushing for 50,000 cycles with calcium carbonate slurry. The depth of abrasion and roughness (Ra) were measured after each 10,000 brushing cycle. The surface texture of the worn samples was examined by SEM. The wear depths of the nanofill Filtek Supreme XT (FIL), the nanohybrides Grandio (GRA), Tetric EvoCeram (TET), and Venus Diamond (VED) increased linearly with numbers of brushing cycles or approximately 80, 12, 600, and 60 μm, respectively after 50,000 strokes. Surface roughness showed virtually no change between 10,000 and 50,000 brushing cycles; the ranking order was TET < FIL < GRA < VED. FIL showed rather uniform abrasion with nanoclusters protruding from the surface. TET was very smoothly abraded without signs of debonding of the prepolymerized particles, whereas GRA and VED showed pronounced wear of the matrix polymer surrounding larger glass filler particles.