In vitro wear rates of tooth-colored direct restoratives

Koichi Shinkai, DDS, PhD,(a) Shiro Suzuki, DDS, PhD,(b) and Yoshiroh Katoh, DDS, PhD(a)

(a)Department of Operative Dentistry, School of Dentistry at Niigata, The Nippon Dental University, Niigata, Japan, and bDepartment of Prosthodontics and Biomaterials, School of Dentistry, University of Alabama at Birmingham, Birmingham, AL, USA.

Purpose: To evaluate the wear resistance of resin-modified glass-ionomer cements and compomers for light loading using an in vitro wear simulation machine.
Materials and Methods: Materials tested included Vitremer, Fuji II LC, Advance, Dyract, and Spectrum TPH resin composite (control). Cylindrical Class I cavities were prepared on occlusally flattened human molars, and the cavities were restored with the respective materials according to the manufacturers’ instructions. Six specimens for each material were used for an in vitro three-body wear testing, and the wear depth was measured with a profilometer on epoxy replicas after 60,000, 120,000, 180,000, and 240,000 cycles. The data were statistically analyzed by ANOVA and Scheffe’s test.
Results: The wear rates of all materials gradually decreased after 60,000 cycles. Advance exhibited the highest wear value at every testing interval, and the TPH control showed the lowest value. The wear values of Vitremer and Fuji II LC were nearly twice that of Dyract at each testing interval. There were significant differences in wear values among all materials, except between Vitremer and Fuji II LC at the 180,000 and 240,000 intervals.
Conclusion: Based upon the results within the range of respective materials tested, it can be concluded that the compomer is significantly more wear resistant than the resin-modified glass-ionomer cements but less wear resistant than the resin composite.
(Int Chin J Dent 2003; 3: 82-90.)

Clinical Significance: The wear resistance of the resin-modified glass-ionomer cements and compomer seem to be insufficient even for the stress bearing area of anterior teeth.
Key Words: tooth-colored filling material, wear resistance, wear simulator.