Figure 3.

(A) Cusp surface of NoPolGZ (not polished graded zirconia) crown after wear testing. Surface images of the wear scar show that the superficial glass has been worn down, exposing a small area of a zirconia/glass graded layer with patches of glass pockets, which are shown in detail in the magnified image (right). (B) Cross section of the crown shows the graded structure (left) with preserved surface glass on the intact cusp. At the center of the wear crater (right), surface glass has been worn out, and again, there are no sliding contact-induced cracks.