Surface properties and color stability of incrementally-filled and bulk-fill composites after in vitro toothbrushing.

PURPOSE: To evaluate the effect of simulated toothbrush abrasion on the surface gloss, the surface roughness and the color stability of incrementally-filled and bulk-fill composites. METHODS: 48 dimensionally standardized composite specimens (n= 8/group) were made from four incrementally-filled composites (Tetric EvoCeram, IPS Empress Direct Enamel, Ceram X mono and Arabesk) and two bulk-fill composites (Quix fil and Tetric EvoCeram Bulk). Before and after toothbrushing simulation the surface gloss was measured by a glossmeter, the surface roughness was evaluated with a profilometer, and the color was measured using a spectrophotometer. RESULTS: Before and after the toothbrush abrasion, IPS Empress Direct Enamel yielded the highest gloss value, while Ceram X mono exhibited the lowest gloss value. Quix fil showed the highest Ra value before the toothbrushing simulation, however, it showed similar Ra value with Ceram X mono and Arabesk after the toothbrushing simulation. IPS Empress Direct Enamel showed the lowest DeltaE after the simulated toothbrushing. Tetric EvoCeram Bulk showed similar gloss value, Ra value, and DeltaE to Tetric EvoCeram after the toothbrushing simulation. Simple regression analysis showed no correlation between the roughness and the gloss, but it showed a positive linear relationship between DeltaE and DeltaRa. (R2= 0.863, P= 0.027). CLINICAL SIGNIFICANCE: The evaluated bulk-fill composites did not exhibit significantly worse surface properties and color stability than incrementally-filled materials after toothbrush abrasion. Color changes of composites caused by toothbrush abrasion were acceptable on the premise that 3.3DeltaE units were considered as acceptable threshold values.