Qualitative and quantitative evaluations of topography for CAD/CAM all ceramic zirconia after different surface treatments

Abstract

Background and objectives: The purpose of this in vitro study was to evaluate the effect of grinding, reglazing and polishing procedures on the surface roughness of monolithic zirconia qualitatively and quantitatively. Materials and methods: Thirty-six disc-shaped yttrium-stabilized zirconium oxide specimens were milled from pre-sintered zirconia blanks using CAD-CAM machine with a diameter of 12mm and thickness of 1.4mm for twenty-seven discs while 12mm and 1.2mm for nine discs as a control group. After that, they were sintered and overglazed. The control group (GA) left untouched while the other twenty-seven specimens were subjected to standardized wet grinded with a coarse diamond rotary instrument. Then they were randomly divided into three groups (nine specimens for each): grinded group (GB) without any additional surface treatment; reglazed group (GC) by adding galze material; polished group (GD) polishing with an intraoral zirconia polishing kit Kenda in a 2-step procedure. Then specimens were evaluated under a stereomicroscope. The surface roughness values were measured with a profilometer for all groups. The mean of surface roughness values was calculated and analyzed using one-way ANOVA and using LSD significant difference tests for comparison between groups (a = 0.05). Results: Stereomicroscopic images revealed that the grinded specimen showed grooves and scratches, reglazed surface showed the same criteria as control with a little bit more evidence of irregularities. While polished specimen appeared smoother and more homogeneity. Statistically significant differences were noted among the experimental groups, in which GB resulted in the highest roughness, GD with the lowest roughness. While GC was close to GA. Conclusions: Roughness significantly increased after grinding, but polishing decreased roughness significantly while glazing restores the smoothness.

The Effect of Glazing on Full Contour Zirconia - A Systematic Review

“…Our results were also in conformity to a study performed by (62) which proved that the glazed full-contour zirconia (monolithic zirconia) have better result than other surface treatment. Our results were in line with previous study by, suggesting that glazing may not be as effective as it could be because the coating layer is not thick enough to adequately fill up the grooves and microcracks on the ceramic surface (63). Another study was done by (64) demonstrated that monolithic zirconia glazing performed lower than alternative surface treatments.…”

Effect of Different Polishing Systems on Surface Roughness of IPS Empress Ceramic Materials

“…In the current study, glazing did not result in minimizing of surface roughness as efficiently as polishing, and this can be because coating layer was not adequately thick for the completion of the grooves and micro-cracks of ceramic effectively as stated by (Azez and Salih, 2019; Hashim and Mansoor, 2021), [23,24].…”

Clinical Evaluation of Wear Behavior of Human Enamel and Chipping of Veneered Zirconia against Monolithic Zirconia (Randomized Controlled Clinical Trial)

“…by using rotary equipment. [37] In our study, surface polishing was chosen for all fabricated restorations of both tested groups. [9] For chipping documentation in this study modified USPHS criteria were used as they provide reliable information regarding the overall long-term success of the restorations.…”