Objective:  The purpose of this study was to evaluate a model for generalized wear.Methods:  A piston-type wear simulator was used to measure wear of two resin composites. The composites were placed in a cylindrical cavity (3 mm depth and 4.5 mm diameter) in a stainless steel fixture. Wear was generated by applying force to the surface with both polacetyl and stainless steel cylindrical-shaped styluses (6.5 mm diameter). A slurry of polymethylmethacrylate beads was used as a food bolus media for the generalized wear model. Wear of the composites was determined by contact profilometry. Wear of the antagonists was also examined. Wear measurements of 12 specimens of each of the two composite materials was measured after 200,000 cycles using the stainless steel and polyacetal antagonists.  ANOVA and Tukey's post hoc tests were used for statistical comparisons.Results:

Material	Stylus	Vol. Loss(mm3)	Max. Depth (microns)	Mean Max. Depth (microns)	Mean Depth (microns)
Z100	Polyacetal	0.056 ± 0.025	16.2 ±5.0	7.0 ± 2.0	2.98 ± 0.9
Z100	Stainless Steel	0.057 ± 0.028	14.7 ± 2.8	6.7 ± 1.1	3.12 ± 0.8
Spectrum TPH	Polyacetyl	0.309 ± 0.090	52.0 ± 8.9	24.9 ± 6.0	12.5 ± 3.8
Spectrum TPH	Stainless Steel	0.326 ± 0.173	69.8 ± 11.7	31.5 ± 5.8	13.1 ± 3.0

Faceting was observed on the surface of the polyacetyl antagonists but not with the stainless steel. Statistical analysis showed a significant difference (p<0.05) when comparing the wear of Z100 and Spectrum TPH. The antagonist materials did not affect any wear values for Z100 or for volume loss and mean depth of Spectrum TPH (p>0.05). Conclusions:  This generalized wear model using metal stylus tips appears to be an effective method for determining wear of resin composites.

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