The friction and wear behavior of dental feldspathic porcelains against uniform Si 3 N 4 balls has been investigated using a small amplitude reciprocating apparatus under simulated oral conditions. The variables of load (10-40 N), reciprocating amplitude (100-500 m), frequency (1-4 Hz) and use of artificial saliva lubrication were selected. Tests lasting up to 10,000 cycles were conducted. The bonded-interface technique was introduced into the wear test for the subsurface damage evaluation. Special attention was paid to the effects of friction conditions of tests, material properties and wear mechanism of dental porcelains. The results show Vita VMK95 possesses a lower friction coefficient and better wear resistance than Cerec Vitablocs MarkII. Among three parameters of the tests on the friction coefficient and wear depth of dental porcelains, the load effect is prominent. Artificial saliva plays an important role in lowering the friction coefficient and wear loss of dental porcelains. Abrasive wear is the main wear mechanism for both, but brittle cracks and delaminations are more frequent for Cerec Vitablocs MarkII, especially under non-lubricated friction. Surface brittle cracks are more dominant in low sliding cycles while subsurface cone or lateral cracks are prominent in high sliding cycles.