Masticatory Wear Resistance Properties of a Universal Shade Composite

Objectives: One critical expectation of filling materials is their ability to withstand masticatory wear comparable to that of natural tooth surfaces. Excessive surface loss of a restoration under normal function is a risk factor for secondary caries and the inappropriate distribution of occlusal forces. The objective of this study was to compare the wear characteristics of the nano filled Omnichroma resin composite restorative material against a nanohybrid resin composite, Filtek Supreme Ultra.
Methods: This laboratory study was completed by preparing sixteen samples of resin composite, each 9.5 millimeters in diameter and polished using a 800-grit wet-sanding technique. Eight samples of Omnichroma and eight samples of Filtek Supreme Ultra were then placed in the Alabama Wear Machine. The Alabama Wear Machine employs stainless steel sliders of uniform diameter as the antagonist. Each stylus provides 75 newtons of peak force with a 30 degree reversing rotational component in each cycle. The testing media slurry, the third body in this experiment, was prepared by mixing orthodontic resin with distilled water. Following 400,000 cycles, surface loss was measured with a scanning profilometer, and statistical analysis completed using an unpaired t test. The samples were imaged using scanning electron microscopy for surface characterization.
Results: A mean surface loss of 7.52 micrometers (S.D. 2.23) was observed in Omnichroma samples, which was significantly greater than the mean surface loss of 2.68 micrometers (S.D. 0.83) observed in Filtek Supreme Ultra samples. The two tailed p-value was less than 0.0001.
Conclusions: In an in vitro setting, the tested universal shade composite showed lower wear resistance. Further evaluation of other universal composites is needed.