Surface Finishing Procedures Research Articles

Effects of different surface finishing procedures and staining solution applications on lightness, chroma and hue of zirconia-reinforced lithium silicate glass ceramics

Aim: The aim of this study was to evaluate the differences in lightness (ΔL), chroma (ΔC), and hue (ΔH) of zirconia-reinforced glass ceramic (ZLS) samples of various thicknesses, which underwent different surface finishing procedures, after aging and staining solutions. Methodology: Sixty samples of ZLS blocks were produced in two different thicknesses (12x14x1 mm, n=30; 12x14x1.5 mm, n=30), and different surface treatments were applied to them (mechanical polishing or glaze; n=15). After polishing and glazing, all samples were cleaned using an ultrasonic cleaner for 10 minutes. Color measurements were taken using a spectrophotometer before and after autoclave aging and immersion in staining solutions (tea, coffee, and coke), and color values were calculated using the CIEDE2000 formula. The Kolmogorov–Smirnov, Shapiro, three-way ANOVA, and Tukey HSD tests were used for statistical evaluation. Results: The common effects of surface finishing treatment, staining solution, and thickness interaction on ∆L and ∆C values were found to be statistically significant (p<0.05), while the common effect on ∆H values was not found to be significant (p>0.05). The ∆L and ∆H values (5.06 ± 1.60 and 2.95 ± 0.61, respectively) were the highest in the groups with 1 mm thickness, mechanical polishing, and immersion in tea solution. The highest ∆C value (4.21 ± 0.35) was noted for the group with 1 mm thickness, mechanical polishing, and immersion in cola solution. Conclusion: Differences in material thickness and the staining solution affected the lightness, hue, and chroma of the ZLS samples. The difference in the surface finishing procedure affected the hue and chroma but not the lightness. How to cite this article: Korkmaz C. Effects of different surface finishing procedures and staining solution applications on lightness, chroma and hue of zirconia-reinforced lithium silicate glass ceramics. Int Dent Res 2024;14(2):57-67. https://doi.org/10.5577/intdentres.538

Metalworking Influence on the Corrosion Behaviour of Sterling Silver and Silver Plated Copper

ABSTRACT Metalworking methods for silver and silver plated copper artefacts may strongly influence their corrosion behaviour. Various surfaces were generated on sterling silver coupons as well as silver plated copper coupons to simulate traditional shaping techniques and surface finishing procedures on historical silver artefacts. Coupons were either polished by hand, by a fabric disc on a polishing machine, or submitted to a hammering process in reference to the as-received state. All samples were subjected to various aging protocols, such as natural aging, a thioacetamide (TAA) gas test (NBN EN ISO 4538:1995) and a Na2S immersion test (NBN EN ISO 8891:1998). The various surface finishing procedures led to marked differences in the tarnishing behaviour which were evaluated by colorimetry, optical microscopy, and scanning electron microscopy.

Surface finishing procedures of CAD-CAM produced monolithic ceramic restorations

CAD-CAM sistemlerinde üretilen tam seramik ve seramik benzeri malzemeler yapılan sınıflandırma sistemine göre; cam maktriks seramikler, polikristalin seramikler ve rezin matriks seramikler olarak üç gruba ayrılmaktadır. Geliştirilen yeni seramik materyallerden monolitik olarak tasarlanıp üretilen restorasyonlar, yüksek dayanıklılığa sahip bir altyapı tarafından desteklenip ışık geçirgenliği fazla olan bir seramikle veneerlenen tabakalı restorasyonlara göre önemli avantajlara sahiptir. Geleneksel olarak veneerlenen veya hasta başında tek seansta üretilen monolitik tam seramik restorasyonlarda, restorasyonun üretimi sonrasında simantasyona hazır düzgün bir yüzey oluşmamaktadır. Bu nedenle restorasyonlar, hastaya teslim edilmeden önce mekanik olarak parlatılmalı veya glaze işlemi uygulanmalıdır. Glaze veya mekanik polisaj ile bitirme işlemleri, restorasyonların üretimi sonrasında meydana gelen yüzey pürüzlülüğünü azaltmak ve optik özellikleri geliştirmek için kullanılabilmektedir. Kullanılan seramik türüne ve üretim yöntemine göre yüzey bitirme işlemleri değişmektedir. Bu literatür derlemesinin amacı, CAD-CAM sisteminde üretilen monolitik seramik restorasyonlarda uygulanan yüzey bitirme işlemleriyle ilgili güncel bilgileri ve konu ile ilgili yapılan çalışmaları sunmaktır.

Effects of dipping time in coloring liquids and surface finishing technique on the color of monolithic zirconia

Objective: The objective of this study was to investigate the effects of liquid coloring in different dipping times and finishing procedures on color difference of precolored and liquid-colored monolithic zirconia ceramics. Materials and Methods: 240 zirconia specimens were divided according to shades of coloring liquid (A1, A2, and A3), dipping time (3, 5, and 7 minutes), and surface finishing procedures (glaze and mechanical polishing) (n=10). CIE L*, a*, and b* values of the specimens were measured and color differences (ΔE) were calculated. The data were analyzed with three-way analysis of variance (ANOVA) and Tukey HSD test (α=.05). Results: Coloring with liquids, dipping time, and finishing procedures significantly affected the CIE L*, a*, and b* values (P<.001). Dipping in coloring liquids decreased the a* and b* values. Higher L* values were obtained in glazing groups than mechanical polishing groups. The ΔE values among the experimental groups were varied from 7.10 to 27.52. The highest color difference was observed in 7 min dipping in A3 liquid and mechanically polished group. Conclusion: The color difference between the precolored and liquid-colored zirconia ceramics are not in acceptable limits. Dipping in coloring liquids and surface finishing affect the color of liquid-colored monolithic zirconia.

Effect of Different Surface Finishing Procedures on Color Stability of Leucite-reinforced Feldspathic CAD-CAM Ceramic

Statement of the problem: The color stability of newly introduced leucite- reinforced feldspathic CAD-CAM ceramic with different surface treatments remains unclear. Objective: This in-vitro study aimed to examine the effect of different surface finishing procedures on the color stability of leucite-reinforced feldspathic CAD-CAM ceramic. Materials & Methods: Twenty-four monochromatic, leucite-reinforced, A2-shaded feldspathic ceramic specimens prepared in 1 mm thickness. The specimens were randomly divided into 3 groups according to their surface finishing methods (n=8): a control group without surface finishing (Group C), surface finishing with polishing discs (Sof-Lex, 3M ESPE), and surface finishing with glaze (Group G). All the specimens were immersed in a coffee solution and kept in an incubator at 37 °C for 14 days. Initial color measurements were made with a digital spectrophotometer and the Commission Internationale de l'Eclairage (CIE) L*a*b* values were recorded. The color measurements were repeated at the ends of the 1st, 3rd, 7th, and 14th days with the spectrophotometer under the same conditions. The color change of the specimens was calculated with the CIEDE2000 (ΔE00) formula. Statistical analysis of the data was performed with a two-way mixed ANOVA and Bonferroni post-hoc tests (α=0.05). Results: Time and surface finishing procedures caused statistically significant color changes in the specimens (P<0.05). However, the interaction of time and surface finishing was not statistically significant (P>0.05). The lowest mean ΔE00 value was observed in Group G on day 14 (0.93 ± 0.74); the highest mean ΔE00 value was found in Group P on the 3rd and 14th days (2.16 ± 0.72). While the C and G groups exhibited similar color change values, Group P caused higher ΔE00 values compared to the glaze application (P<0.05). Conclusions: Based on the findings of this study, glaze application led to less color change compared with disk polishing. Glazing can be preferred to polishing to ensure long-term color stability in leucite-reinforced feldspathic ceramics.

Evaluating the color stability of two esthetic ceramic materials after different surface treatments and accelerated aging procedures

Aim: Observing and evaluating the long/short-term discoloration tendency of the esthetic prosthetic materials of lithium disilicate-based glass-ceramics (IPS e.max CAD LT) and leucite-based feldspathic glass-ceramics (VITA Mark II) materials, which are esthetically very close to each other at first glance.
 Methodology: 80 samples of A2 colored lithium disilicate and feldspathic blocks samples were overglazed and polished separately to evaluate the surface treatment procedures according to CIELAB color coordinates. For accelerated aging purposes, half of the examples were treated to red wine, and the other half were treated to coffee. Color changes were calculated using the ΔE formula. The results were put into record as ΔE-1, ΔE-2, and ΔE-3. Records of the results were evaluated using IBM SPSS Statistics Standard Concurrent User V 25 statistics package program. Data distribution regarding numerical variety and changes were evaluated using the Shapiro Wilk normality test and Q-Q graphics. 
 Results: The data was evaluated using O'Brien clinical color tolerance scales. None of the samples has shown a perfect (ΔE=0-0.5) color match after 4 weeks of accelerated aging. Every group has shown results of significant statistical changes at various rates and percentages and divided into 4 subgroups as excellent, good, clinically acceptable and incompatible categories.
 Conclusion: Since aging procedures affect ceramic systems' ΔE values in a variety of ways, the aging protocol utilizing in vitro aging techniques for color changing should be evaluated alongside ceramic type and surface finishing procedures.

WEAR OF HUMAN ENAMEL OPPOSING ULTRA-TRANSLUCENT ZIRCONIA WITH TWO SURFACE FINISHING PROCEDURES

ABSTRACT Introduction: With the advancement of material technology, CAD-CAM zirconia restorations have become increasingly popular. Their influence on the opposing tooth surface wear requires further investigation to ensure clinical occlusal stability. Objectives: to determine wear behavior and surface roughness of enamel when opposed by ultra-translucent monolithic zirconia (UTMZ) with two surface finishing procedures (glazed or polished). Materials and Methods: This in vitro study consisted of three groups; Group A: enamel opposing glazed ultra-translucent zirconia, Group B: enamel opposing polished ultra-translucent zirconia, and Group C: enamel opposing enamel as a control group. A modified custom-made tooth brushing machine was used for chewing simulation. The zirconia specimens and the enamel antagonists were subjected to 120,000 cycles with vertical load 49N. The amount of wear was determined based on percentage of weight loss. Qualitative and quantitative analysis of the specimens’ surfaces ware carried out using 3D laser scanning microscope. Data were analyzed with a 1-way ANOVA and Games-Howell post hoc tests (α=0.05) Results: Enamel surface wear was significantly affected by the opposing surface after chewing simulation, with antagonist natural enamel causing the greatest wear and polished UTMZ the least. There was a significant increase in the surface roughness of both the zirconia specimens and the enamel antagonists after wear test. Conclusion: Within the limitations of this study, polished UTMZ was shown to be more wear friendly to the antagonist enamel than both the glazed UTMZ and natural enamel. Increase in the surface roughness leads to an increase in the amount of antagonist wear.

Effect of surface finishing and polishing procedures on color properties and translucency of monolithic zirconia restorations at varying thickness.

This study aimed to assess the impact of monolithic zirconia thickness on its color properties after different surface finishing and polishing procedures, and following aging in coffee solution. Two types of monolithic zirconia brands [Prettau Anterior (PA) and DD Cubex2 (DDC)] with three different thicknesses: 0.5, 1, and 1.5, and 10 mm diameter were tested. The color properties were evaluated after various surface finishing procedures (glazing, adjusting with burs + glaze, polishing, adjusting with burs + polishing) and after 5,000 cycles in a coffee solution were evaluated. The differences in color (ΔE) and translucency, were calculated and statistically analyzed by three-way ANOVA and pairwise comparison (α=0.05). The brand, material thickness, and surface finishing protocol before and after coffee thermocycling had significant effect on color variations (p< 0.001). For translucency, 3-way ANOVA revealed a significant interaction between the material thickness and surface finishing protocol following aging in coffee solution (p< 0.001), however no significant interaction was observed following the surface finishing protocols (p= 0.247). The optical properties of monolithic zirconia ceramics can be influenced by the material brand, material thickness and the procedure of surface finishing and polishing. Clinicians should take into consideration the potential change of the color properties of monolithic zirconia restorations following both contouring and occlusal adjustment procedures and coffee intake.

Effects of Surface Finishing Procedures on Corrosion Behavior of DMLS-AlSi10Mg_200C Alloy Versus Die-Cast A360.1 Aluminum

In this study, the impact of surface finishing procedures on the corrosion resistance of an AlSi10Mg_200C alloy manufactured through direct metal laser sintering (DMLS) versus its die cast counterpart was investigated. The as-printed DMLS-AlSi10Mg_200C and as-cast A360.1 alloys were subjected to various surface finishing processes including grinding and sandblasting. The corrosion performance of the surfaces was then evaluated using a potentiodynamic polarization test and electrochemical impedance spectroscopy in an aerated 3.5 wt.% NaCl solution. The results highlighted the better corrosion resistance of DMLS-AlSi10Mg_200C than its cast counterpart with a similar surface finish. The grinding of both as-printed DMLS and as-cast samples was found to initially deteriorate the corrosion performance of the surface by exposing cathodic sites to the electrolyte. However, for longer immersion times and after complete repassivation of the surface, the ground surface showed the highest resistance to the selective attack. The sandblasting process was found to have a detrimental effect on the corrosion resistance of both alloys.

Color Stability of CAD/CAM Ceramics Prepared with Different Surface Finishing Procedures.

To investigate the color stability of zirconia-reinforced lithium silicate glass-ceramic and lithium disilicate reinforced glass-ceramic, which were prepared with various surface finishing procedures, following 1-week, 2-week, 1-month, and 2-month storage in various beverages, and after the application of polishing paste. Lithium disilicate glass-ceramic (IPS e.max CAD HT) and zirconia-reinforced lithium silicate ceramic (Vita Suprinity HT) CAD/CAM blocks were sectioned with a diamond saw (Metkon) under water cooling into 1.5 × 7 × 12mm dimensions (N = 120). All specimens were polished with silicon carbide paper (600-, 800-, and 1200-grit) under water for 120 seconds. The specimens were prepared using 3 surface finishing procedures: glaze, mechanical polishing, and external staining and glaze in accordance with manufacturers' instructions. Then, each group was divided into 2 storage subgroups, black tea and coffee (n = 10/group). Color values were measured in CIELAB color space with dental spectrophotometer (VITA Easyshade) at the initial stage, and following 1-week, 2-week, 1-month, 2-month storage, and after fine-grit polishing paste application (Proxyt). Color changes (ΔE) were calculated and statistically analyzed using ANOVA followed by Bonferroni corrected post-hoc tests using Number Cruncher Statistical System 2007 (α < 0.05). For lithium disilicate glass-ceramic, glaze procedure showed statistically lower color change values than mechanical polishing and external staining and glaze surface finishing groups (p < 0.05) following storage in both beverages, whereas for zirconia-reinforced lithium silicate ceramic, glaze procedure showed statistically lower color change values than mechanical polishing, but statistically insignificant values with respect to external staining and glaze group, following storage in both beverages. Lithium disilicate glass-ceramic groups showed statistically lower or statistically insignificant color change values with respect to zirconia-reinforced lithium silicate ceramic groups, except for the external staining and glaze surface finishing group in coffee. Significantly lower discoloration values were obtained following polishing paste application, with respect to 2-month storage in beverages (p < 0.05). Glazing alone led to more color stability with respect to mechanical polishing and external staining and glaze for zirconia-reinforced lithium silicate and lithium disilicate glass-ceramic. Lithium disilicate glass-ceramic showed higher color stability compared to zirconia-reinforced lithium silicate ceramic. Polishing paste resulted in a decrease in discoloration to clinically acceptable values.

Effect of Artificial Saliva Storage on Microhardness and Fracture Toughness of a Hydrothermal Glass‐Ceramic

This study evaluated the effect of artificial saliva storage on the hardness, crack length, and fracture toughness of a glazed, polished, and bleached hydrothermal low-fusing glass-ceramic (Duceram LFC). Forty ceramic discs were constructed. The discs were assigned to four groups (n = 10) according to their surface finish: Gp1 -- Autoglaze, Gp2 -- Autoglaze/ground/diamond-polished, Gp3 -- Overglaze, Gp4 -- Overglaze/ground/diamond-polished. Each group was further divided into two subgroups forming eight total subgroups (n = 5). Subgroup A was unbleached; Subgroup B was bleached. Testing was performed before and after 21 days of artificial saliva storage. Data were presented as means and standard deviation (SD). ANOVA was used, along with Duncan's post hoc test for pairwise comparison between the means when ANOVA test was found significant (p< or = 0.05). Surface treatments such as glazing, polishing, and bleaching, saliva storage, and the interaction between these variables had a statistically significant effect on mean values of microhardness, crack length, and fracture toughness of the specimens. There was a statistically significant increase in microhardness and fracture toughness mean values, while crack length values decreased after saliva storage. Polished specimens recorded the smallest crack lengths and fracture toughness, and highest hardness values before and after saliva storage. No difference in fracture toughness values was evident between glazed and polished specimens. Mean crack lengths decreased after saliva storage in all the tested specimens. Hardness values increased after saliva storage. The autoglazed group showed significantly higher fracture toughness, lower crack length, and microhardness than the overglazed group. Surface finishing procedures and artificial saliva storage had a statistically significant effect on mean values of microhardness, crack length, and fracture toughness. This in vitro study suggests that fracture toughness of ceramics may be affected by different surface treatments such as glazing, polishing, bleaching, or a combination; however, in this study Duceram LFC proved its self-healing property after 3-week storage in artificial saliva.

The effect of finishing on the anodic polarization of high‐copper amalgams

The influence of surface finishing procedures on the corrodibility of high-copper amalgams was measured. Anodic polarization curves were determined in Ringer's solution for amalgam samples made from a dispersion and a ternary alloy. Three types of finishes were compared: as carved, burnished, and polished. The polarization curves of the burnished and polished specimens were statistically similar (P greater than 0.05) at all potentials investigated. The carved samples exhibited higher corrosion currents at most of the potentials investigated.

Optical Coatings for High Energy ZnSe Laser Windows

The development of surface finishing and coating technology at 10.6 microm for polycrystalline ZnSe laser windows is presented. Optical evaluation of the coated windows shows that the 10.6-microm absorption and reflection can be held to less than 0.1% per surface. Surface finishing procedures, theoretical coating designs, and recent experimental results for antireflection coatings for ZnSe are presented.