An In Vitro Study to Identify a Ceramic Polishing Protocol Effecting Smoothness Superior to Glazed Surface

Abstract

Polishing is taken up as an alternative to reglazing after adjustments of glazed ceramic prosthesis. An in vitro study was carried out to evaluate three different ceramic polishing systems and their combinations to identify a method that would achieve surface smoothness superior to the glazed surface. 77 glazed feldspathic porcelain disc surfaces, of diameter 12.5 mm and thickness 2 mm were constituted into seven groups of 11 specimen surfaces each. The glazed surfaces in the first group served as control (C). They were not subjected to deglazing or polishing. The remaining 66 surfaces underwent deglazing. The deglazed surfaces in the second group (D) were retained as such and did not undergo polishing. The deglazed surfaces in the third group (Wh), were polished using a polishing wheel (CeraMaster). In the fourth group (K), an adjustment kit (Porcelain Adjustment kit) was used for polishing the deglazed surfaces. The fifth group (Wx) was polished with diamond particle-impregnated wax (Dura-Polish Dia). In all these three groups, polishing was done for 40 s. The deglazed surfaces of the sixth group (WhWx) were polished initially with polishing wheel for 40 s and then with diamond particle-impregnated wax for 40 s. In the seventh group (KWx), the deglazed surfaces were polished with an adjustment kit (Porcelain Adjustment kit) for 40 s followed by diamond particle-impregnated wax (Dura-Polish Dia) for 40 s. In the sixth and seventh groups, the total polishing time was 80 s each. From each group, one specimen was set aside for scanning electron microscopy (SEM). The remaining ten specimens in each group underwent colorimetry and profilometry. Colorimeter (Minolta CR-200b ChromaMeter; Minolta, Osaka, Japan) was used to measure parameters according to CIE L*a*b* colour system and colour difference (ΔE) between control and other groups were calculated. Profilometer (Talysurf CLI 2000) was used to measure the surface roughness (Ra). The data were statistically analysed by one way ANOVA and Tukey HSD tests. The colour differences were well within the acceptable range of 3.3 units in groups subjected to polishing. Polishing with porcelain adjustment kit alone, diamond particle-impregnated wax alone or polishing wheel followed by diamond wax created surfaces with smoothness comparable to the glazed surfaces. The group polished by adjustment kit followed by diamond particle-impregnated wax showed surface roughness significantly less than the glazed surfaces. The SEM observations were corroboratory. It can be concluded that polishing with porcelain adjustment kit followed by diamond particle-impregnated wax, created surfaces significantly smoother than the glazed specimens with no significant negative effect on colour and thus can be a technique superior to glazing.

Influence of polishing systems on roughness and color change of two dental ceramics

“…In laboratorial tests, Manjuran and Sreelal41 stated that the combination of polishing system and polishing paste (Shofu Inc.) produced smoother surfaces than the feldspathic ceramics (Vintage Halo, Shofu Inc.). Sarac et al24 described that the use of both a polishing system (Shofu Inc.) and the polishing paste (Ultra II, Shofu Inc.) together generated surfaces as smooth as the ones of the feldspathic ceramic glaze (Vitadur Alpha, VITA).…”

The Influence of Oral Environment on the Optical Properties of Heat- pressed Ceramics

“…Some authors found that the initial smoothness of the glazed surface of ceramic to be superior to the polished surface [16,17] and some authors considered that the polished surface could equal the glazed surfaces. The results of this study concluded that it depends on the type of the ceramic.…”

“…Ceramic corrosion can affect the roughness of the materials, which can affect the survival rate of the prosthetic restoration [14,15]. Ceramics can be clasified by their microstructure (type of crystalline phase and glass composition), processing technique powder/liquid,pressed, or machined), and clinical application [16]. Furthermore, polishing and glazing are also applied to finalize surface texture of the ceramic material, reduce roughness and enhance light transmission influencing the optical properties.…”

Polishing of Ground Y-TZP Ceramic is Mandatory for Improving the Mechanical Behavior

“…After grinding, manufacturers usually recommend a polishing protocol, which should be executed to achieve a smooth and shining surface (5); and/or a glazing procedure on the surface again to promote a smooth and shining surface (8); and/or a heat treatment/annealing, that consists to subject the zirconia to a specific heat treatment, with temperatures around 1000 ºC for 15 min, aiming for the complete reversion of m to t phase (9).…”