Analysis of behavior of the wear coefficient in different layers of acrylic resin teeth.

STATEMENT OF PROBLEM: Analysis of the wear coefficient (k) of the superficial and deep layers of acrylic resin teeth can help predict denture durability, but little has been published on the wear coefficient of denture teeth. PURPOSE: The purpose of this in vitro study was to determine the k value for the superficial and deep layers of the acrylic resin teeth of 6 different brands by using the fixed-ball microabrasive wear method. MATERIAL AND METHODS: Six artificial tooth specimens of 4 commercial brands were tested: Artiplus IPN (Ar), Biotone IPN (Bi), Magister (Ma), Premium (Pr), Trilux (Tr), and SR Vivodent (Vi). Two specimens from each brand were created, one for the superficial layer and the other for the deep layer. The test was performed on fixed-ball microabrasive wear equipment set to operate at a constant normal force of 0.5 N and a rotation speed of 100 rpm. The test time periods were 5.00, 8.33, and 11.66 minutes. The characteristics of the wear craters were measured by using an optical microscope at a magnification of ×50 and Leica Microsystems software. Wear coefficient (k) values were deduced by using the Archard equation for abrasive wear, Q=k·N, and were analyzed by using 1-way analysis of variance, complemented by the Tukey HSD test (α=.05). A different analysis was used for each layer. RESULTS: The analysis of variance of the wear coefficient revealed significant differences among the groups regarding the superficial layers (P=.009). The Tukey HSD test showed that the k values for the superficial layers of Artiplus specimens were significantly lower than those of the Vivodent and Magister specimens. CONCLUSIONS: One brand (Ar) presented significantly lower wear coefficient value for the surface layer. No difference in wear coefficient values was found among the tooth brands for the deep layer.