Compared to polished zirconia, a tooth veneered with ceramics is 10,000 times more abrasive. The porous structure of the layered ceramic acts like sandpaper and causes wear on natural dentition.
This phenomenon can be illustrated using a practical example:
Rubbing our hands together creates abrasion, which can cause open skin areas. Rubbing our hands against a window pane makes the hand slip on the glass surface. This causes a minimal friction and heat, but no abrasion. Something similar is happening when sintered zirconia meets the natural tooth.
Zirconia in sintered state is perfectly smooth and non-porous, so that it slips on the natural tooth without friction, same as a hand on a window pane.
In general we can say:
The harder and smoother the material, the lower is the material wear caused by friction and hence also abrasion.
Schematic view of the abrasion in the indenter according to each sample