Wear characteristics in a two-body wear test.

OBJECTIVES

A previous report compared spherical steatite (ceramic enamel substitute) abraders with those of natural enamel in a two-body wear test. The wear rates and coefficients of friction of the two abraders against various composites and an amalgam were well correlated although the wear rates were slightly higher with steatite. This report investigates the characteristics of the worn abrader and specimen surfaces.

METHODS

Scanning electron microscopy and laser profilometry were used.

RESULTS

Similar wear characteristics were found for the two types of abraders. Adhesive wear was evident for the amalgam, Dispersalloy (Johnson & Johnson), and the heat/pressure-cured microfill composite, Isosit (Ivoclar-Vivadent). Abrasion was seen with the hybrid composite, Occlusin (ICI), and, to a lesser extent, the microfill composite, Heliomolar (Ivoclar-Vivadent). The appearance of the worn small particle hybrid composite, Brilliant Dentin (Coltène), suggested that fatigue and delamination were involved. Laser profilometry showed that the hybrid composites caused much greater wear to the abraders than either the microfill composites or amalgam. The Ra values of the worn abraders and specimens were similar, suggesting conformal contact between them and endorsing the well controlled conditions of the wear test.

SIGNIFICANCE

The results of this and other publications suggest that steatite can be used as an alternative to enamel in performing two-body wear tests on dental composites. This should help significantly in materials evaluation and development.