Effects of the test method on wear measurements in dental enamel/ceramic tribosystems

Because of the complex shape and variability of cusps/crowns and the absence of a standardized method, wear of human enamel and artificial dental ceramics is notoriously more difficult to characterize by in-vitro tests than the other mechanical properties relevant to tooth function. A critical comparison is made of two engineering methodological approaches to investigating dental enamel/ceramic tribosystems: ball-on-three-disks and pin-on-disk, with and without attendant machining of enamel specimens, respectively. Differences in wear rate measurements in tribosystems without and with abrasive particles (two- and three-body wear, respectively) are analyzed. Pin-on-disk allows for more accurate measurements of the occlusal enamel wear rate, while ball-on-three-disks facilitates investigations of transient effects (wear transitions). Using the more accurate pin-on-disk method, a preliminary investigation is made of the effect of polishing of dental zirconia on the wear of enamel antagonists. Implications for the judicious selection of test methods and interpretation of experimental wear results are discussed.