Toothbrush Abrasion of Flowable Resin

Abstract

The physical and handling properties of flowable resin composites have been improved by modifying the materials. Furthermore, nano-fill and nano-hybrid flowable resin composites designed to combine high mechanical properties and superior polishing surfaces have been developed and have recently become commercially available. The purpose of this study was to investigate the toothbrush abrasion of flowable resin composites including nano-fill and nano-hybrid materials. The relationships between toothbrush abrasion and the following material properties were also investigated: surface hardness, surface roughness and filler content. Nine flowable resin composites and a paste type of a resin composite were used. Toothbrush abrasion was conducted in a toothbrush simulator using calcium carbonate slurry for 50,000 cycles. The maximum wear depth was measured with a profilometer after each 10,000 brushing cycles. Vickers hardness numbers were determined after grinding the surface with SiC paper, grit #1000. Surface roughness (Ra) was determined on the ground surface and on the brushed surface. The surface texture of the worn samples was examined by SEM. The wear depth of every material increased linearly with the number of brushing cycles. After 50,000 brushing cycles, the wear depth of Tetric® N-Flow was the highest of 9 flowable resin composites, followed by Palfique Estelite LV High Flow. The wear depth of Clearfil® Majesty® LV was the lowest, followed by Filtek™ Supreme XT Flowable Restorative. Surface hardness, surface roughness before brushing and filler content obtained from the manufacturer's information had no impact on the toothbrush abrasion of the flowable resin composites. However, the materials with low wear depth showed much higher surface roughness after brushing. From the SEM observations, the materials with larger particles including glass fillers and nanoclusters showed low wear depth.