Abstract:

Objective

To explore the effect of different polishing and glazing techniques on the surface roughness of feldspathic ceramic via multiple evaluation parameters.

Methods

100 disc-shaped ceramic specimens （Vita VMK 95， 5.0 mm in diameter and 2.5 mm in thickness）were randomly divided into five groups （n=20）， in which porcelain surfaces were ground sequentially with abrasive sandpapers to 220^#， 320^#， 600^#， 800^# and 1200^# under water-cooling condition， respectively.Each group then divided into two subgroups （n=10） by means of glazing techniques， namely the overglazing group and the autoglazing group.The surface roughness parameters （including Ra， Rz， Rp and RSm） of the same specimen were measured by a profilometer both before and after glazing.And the surface characteristics of the representative specimen from each group were observed by scanning electron microscopy （SEM）.

Results

The specimens ground 220^# sandpapers displayed the highest Ra value after glazing，（0.532±0.109）μm in the overglazing group and （0.552±0.123）μm in the autoglazing group； while those sequentially polished to 1200^# sandpapers obtained the lowest Ra value，（0.201±0.050）μm in the overglazing group and （0.126±0.016）μm in the autoglazing group.Both autoglazing and overglazing techniques could produce smooth ceramic surface.

Conclusion

Different polishing and glazing techniques have significant effects on the surface roughness of dental ceramic.

Key words: Dental porcelain, Polishing, Glazing, Surface roughness