Induced damage zone in micro-fine dental finishing of a feldspathic porcelain

Intraoral adjustment of ceramic prostheses involving micro-finishing a feldspathic porcelain using very fine diamond burs was reported in Med Eng Phys 2008;30:856-864 with respect to finishing force, energy and surface integrity. The measured finishing forces were found to be very small. The remaining question is whether these small forces in the micro-dental finishing induced any subsurface damage to the porcelain. This paper addresses the finite element analysis (FEA) of the finishing-induced stresses and the depths of subsurface damage in micro-fine finishing. It also reports on the measurement of the subsurface damage using scanning electron microscopy (SEM). The results indicate that while finishing using fine diamond burs diminished subsurface damage, damage depths of smaller than 18 microm remained depending on the bur depth of cut and feed rate. These damages can only be minimized under very fine finishing conditions.