An in vitro investigation to compare the surface roughness of auto glazed, reglazed and chair side polished surfaces of Ivoclar and Vita feldspathic porcelain

Abstract

The change in surface roughness after different surface finishing techniques has attracted the attention of several prosthodontists regarding wear of opposing teeth or restorative material and the strength; plaque retention and appearance of the restoration. However, there is considerable controversy concerning the best methods to achieve the smoothest and strongest porcelain restorations after chair side clinical adjustments. The purpose of this in vitro study was to compare the average surface roughness of a self-glazed surface, a chair side polished surface and a reglazed surface of ceramic. Two feldspathic porcelain, namely VITA VMK94 (Vita Zahnfabrik, Bad Sachingen, Germany) and IVOCLAR CLASSIC (Vivadent AG, FL-9494 Schaan, Liechtenstein) were selected to fabricate 20 specimens of each in the shape of shade guide tabs. A medium-grit diamond rotary cutting instrument was used to remove the glaze layer, and then the surface of half the specimens were re-glazed and the other half were polished using a well-defined sequence of polishing comprising of: Shofu porcelain polishing system, White gloss disc/polishing wheel, Silicone cone with diamond polishing paste and finally with small buff wheel with pumice slurry. The surface roughness (Ra) (μm) of the specimens was evaluated using a profilometer and scanning electron microscope. The data were statistically analyzed by using Student's t test. The results had shown that there is no statistically significant difference both quantitatively and qualitatively, between the surface roughness of reglazed and chair-side polished surface. In addition, both reglazed and chair-side polished surfaces are better than the autoglazed surface. Within all the groups, there is no significant difference between companies. Polishing an adjusted porcelain surface with the suggested sequence of polishing will lead to a finish similar to a re-glazed surface. Therefore chair-side polishing can be a good alternative to reglazing for finishing adjusted porcelain surface.

Surface Roughness of Monolithic and Layered Zirconia Restorations at Different Stages of Finishing and Polishing: An In Vitro Study

“…These findings are in agreement with previous reports . The glaze produces a smooth and regular surface with less wear to antagonist enamel and restoration and less plaque accumulation . The layered digital group (TriLuxe forte) demonstrated the highest Ra and Rz values at the glazed stage.…”

“…The final polishing with diamond paste did not show a significant reduction in surface roughness of monolithic and veneered zirconia, which was also in agreement with previous studies . Contrary to this, other studies have shown that diamond paste improved the surface smoothness of some ceramic restorations . These differences with other studies could be related to the different types of ceramic restorations used in this study and the protocol of finishing and polishing.…”

“…[23][24][25] Some studies reported that polishing was as effective as glazing in reducing surface roughness of ground ceramics. [26][27][28][29][30][31][32][33] Similar findings were reported for monolithic and opaque zirconia. 34,35 On the other hand, other studies reported that glazing is the best procedure for obtaining surface smoothness.…”

“…Porcelain polishing reduced surface flaws and defects and enhanced the resistance of the restoration to fracture . Some studies reported that polishing was as effective as glazing in reducing surface roughness of ground ceramics . Similar findings were reported for monolithic and opaque zirconia .…”

“…27,30,40 The glaze produces a smooth and regular surface with less wear to antagonist enamel and restoration and less plaque accumulation. 26,28 The layered digital group (TriLuxe forte) demonstrated the highest Ra and Rz values at the glazed stage. Surface roughness has been reported to be affected by milling and post-milling procedures.…”