Wear of aluminum oxide antagonists by commercially available composites and compomers.

PURPOSE To investigate the wear of aluminum oxide antagonists by 19 light curing, commercially available composites and compomers. The influence of the filler particle size of the composites, the filler particle material and the filler particle morphology was determined. METHODS Occlusal contact wear of the antagonists was simulated in a sliding wear test. Eight antagonists and specimens of each material were tested in a pin-on-block design with oscillating sliding of an aluminum oxide antagonist (Degussit antagonist, 5 mm diameter). After 50,000 cycles the contact area was evaluated using a dedicated software (UTHSCA image tool for windows V 2.0) under a light microscope. The size of the contact area was measured. RESULTS Three types of boundaries of the contact area could be observed: (1) Sharp boundary, (2) No sharp boundary but easy to identify, and (3) No sharp boundary and difficult to identify. The method of Pearson was used to calculate the correlation coefficients. The coefficient of determination between the ranking of the measured contact area and the ranking of the maximum particle size was r2= 0.46 (P> 0.05). Composite materials with the same particle size were ranked by their filler content (wt. %).