Glaze Materials Research Articles

Development of self-cleaning matte ceramics based on polycrystalline hexaferrite and its application in oil removal

This study focused on developing self-cleaning matte ceramics based on polycrystalline hexaferrite for oil removal. The ceramics were glazed using glaze materials BaO, Fe2O3, ZnO, and TiO2 with varying ZnO:TiO2 ratios. The aim of this research was to determine the glaze composition that was able to provide the best self-cleaning/PA removal characteristics. After calcination at 1200°C, a polycrystalline hexaferrite compound formed, BaFe12ZnTiO19. All ceramic samples demonstrated palmitic acid (PA) photodegradation, with CM3 (ZnO:TiO2; 1:1) showing the highest efficiency. This efficiency correlated with CM3’s lowest bandgap of 1.43 eV. The photodegradation of PA by CM3 follows first-order kinetics with rate constants of 0.0482 min−1 under UV irradiation and 0.0179 min−1 under visible irradiation. CM3 displayed exceptional durability, maintaining PA removal even after prolonged use, making it optimal for practical applications.

Influence of attaching mechanical retentive devices onto frameworks on fracture resistance of implant-supported zirconia crowns.

This study investigated the fracture load of implant-supported zirconia crowns (IZCs), in which indirect composite resin or feldspathic porcelain was layered onto zirconia frameworks with mechanical retentive devices. Three different zirconia frameworks were assessed: attaching mechanical retentive devices on glaze and opaque porcelain materials (GL and OP groups, respectively), and no attaching mechanical retentive devices (ND group). The frameworks were layered using feldspathic porcelain (FP veneer) and indirect composite resin (IC veneer). Fracture load of the specimens was measured. In FP veneer, the GL group recorded the highest fracture load. In the IC veneer, the GL and OP groups had significantly higher fracture load than the ND group. The fracture resistance of IZCs can be enhanced by applying glaze material before attaching mechanical retentive devices for porcelain layering. The mechanical retentive devices effectively yielded mechanical interlocking between the zirconia frameworks and the IC veneer in GL and OP groups.

The effect of composition and holding time on glaze production using basalt rock as a base

This research studied the potential use of local basalt and feldspar from Lampung Province, Indonesia, as glaze materials. Frit(s) are composed of changing basalt-to-feldspar weight ratios of A (30:70), B (50:50), C (70:30), and D (100:0) w/w%. The added 20% boric acid to the total weight reduces the process temperature to 1,000oC with holding times of 1, 4, and 8 hr(s). Based on the chemical composition test of the specimen, the four variations of the sample have SiO2 content above 40%, and the average SiO2/Al2O3 ratio is 4 and 5, which is usually a low-alumina glaze that will cause a glossy effect and have an amorphous structure. At point 2theta 29o, amorphous forms. Quartz (SiO2), albite (NaAlSi3O8), anorthite (CaAl2Si2O8), and coesite (SiO2) phases were discovered in the glaze specimens. The anorthite phase in glass-ceramic glaze gives a transparent glaze color due to the amorphous glassy phase formed during heat treatment. The findings of this study suggest that local materials based on basalt and feldspar may be used as glaze materials to provide a smooth texture and surface; the glaze layer is evenly distributed, can follow the full surface contour of the test specimen, and has low porosity.

Do Polishing Methods and Colorant Beverages Affect the Color Stainability of 3D-printed Permanent Restorations?

Aim: This in vitro study evaluated the effect of polishing methods on the color stainability of 3D-printed permanent restorations while immersed in colorant beverages (distilled water, tea, coffee, and red wine) for 30 days. Materials and Methods: A total of 120-disc-shaped samples (10 mm × 1.5 mm) were fabricated using a stereolithography printer (Formlabs 3B, Formlabs, Massachusetts) with a three-dimensional (3D)-printable permanent resin (Permanent Crown, Formlabs, Massachusetts). The samples were polished with mechanical polishing, Optiglaze (GC Dental Products Corp, Aichi, Japan), or Vita Akzent LC (VITA Zahnfabrik, Bad Säckingen, Germany) ( n = 40). Initial color measurements were performed using a spectrophotometer (VITA Easyshade V; Vita Zahnfabrik). Then the samples were divided into four different subgroups depending on beverages immersed in distilled water, coffee, tea, and red wine ( n = 10). After immersion in beverages for 30 days, color measurements were repeated. Color changes were calculated using the CIEDE2000 color change (Δ E00) formula. Δ E00 was evaluated according to 50:50% color perceptibility (PT00 = 0.81) and acceptability (AT00 = 1.81) thresholds. A two-way analysis of variance (ANOVA), Tukey HSD test with Bonferroni adjustment, and paired-sample t-tests were used for statistical evaluation. Results: The highest ΔE00 was noted in mechanical polishing groups ( p < .001). Red wine caused the most significant discoloration in the mechanical polishing group ( p < .05). ΔE00 of mechanical polish groups showed a significantly higher color change than the perceptibility and acceptability thresholds ( p < .001). Optiglaze can reduce 3D-printed permanent restoration discoloration caused by all beverages, Vita Akzent LC can reduce discoloration caused by tea and red wine. Conclusion: Glaze materials can reduce the restoration discoloration caused by colorant beverages.

SrMn1-xFexO3-δ (x = 0–1) black ceramic pigment: Synthesis, color properties, and application

In this work, SrMn1-xFexO3-δ (x = 0–1) black ceramic pigments were synthesized by the solid-state method. The research explores the influence of calcination temperature and iron ion doping on the color properties of the pigments. Furthermore, the potential applications of SrMn1-xFexO3-δ pigments in ceramic glaze and heat-absorbing materials are also discussed. The findings reveal that the synthesized SrMnO3 pigment exhibits the lowest L*-value (22.30) at 1100 °C, although it displays a slight blue hue. To optimize the color properties of the SrMnO3 pigment, iron ion doping is employed. When the doping level of iron ions is 50 mol.% (i.e., x = 0.5), the L*-value of the SrMn0.5Fe0.5O3-δ pigment calcined at 1000 °C significantly decreases to 19.77, while the a*- and b*-values approach 0, resulting in a pure black color. This is attributed to the high surface roughness, low band gap energy, and substantial oxygen vacancies present in the SrMn0.5Fe0.5O3-δ pigment. The tinting mechanism of the SrMn1-xFexO3-δ pigment in the ceramic glaze is classified as "ion tinting", wherein the glaze color relies on the concentrations of Mn and Fe ions. When the pigment content reaches 36 wt%, the L*-value of the glaze drops to 4.94, showing a deep black shade. Additionally, the SrMn0.5Fe0.5O3-δ pigment exhibits excellent sunlight absorption capabilities, with a near-infrared reflectance (R*) of only 5.04%. This research presents a black ceramic pigment with various advantages, such as simplified processing, affordability, environmental friendliness, and exceptional color performance.

Effect of thermocycling on the mechanical properties, inorganic particle release and low temperature degradation of glazed high translucent monolithic 3Y-TZP dental restorations

The influence of thermocycling on the surface deterioration of glazed monolithic high translucent 3Y-TZP dental restorations is still unclear. The purpose of this study therefore was to evaluate low temperature degradation (LTD), elemental release and surface degradation pattern after five years of simulated clinical time. A total of 123 specimens were prepared from second-generation high translucent 3Y-TZP as per ISO 6872:2015 standards (3 mm × 4 mm × 30 mm). They were classified as per glazing and thermocycling protocol; group CPT, DGT and IGT. Glaze materials were applied on one surface of the specimen and subjected to a thermocycling in artificial saliva, four-point bending test, inductively coupled plasma mass spectrometry (ICP-MS), scanning electron microscopy (SEM), energy dispersive x-ray spectroscopy (EDX) and x-ray diffraction (XRD). Flexural strength, characteristic strength and Weibull modulus values were derived from four-point bending test. Descriptive fractographic analysis of surfaces was conducted to observe the surface degradation characteristics and point of failure. Control/no glaze with thermocycling (CPT = 621.5, 1σ = 117.0 MPa) presented higher flexural strength values compared to glaze I with thermocycling (442.4, 1σ = 45.4 MPa) and glaze II with thermocycling (534.3, 1σ = 46.3 MPa). Characteristic strength from Weibull analysis also observed higher values (669.2 MPa) for the control specimens. XRD analysis showed that monoclinic volume fraction (Vm = 11.0, 1σ = 0.7%) was highest in control specimens. Fractographic analysis suggested that there was no correlation between the point of failure initiation and mean flexural strength values. Glazing protected the high translucent 3Y-TZP surface against LTD during thermocycling but negatively impacted on the flexural strength.

Innovative Technology of Chocolate Covered Multi Layered Chips

Topicality. The assortment of chips in the world market and technologies of their production are analyzed in this article. The main tendency of chips market is the growing demand for products from local natural raw materials, which retain all the nutrients to the highest degree. Therefore, it is important to elaborate a technology for chips production, which is supposed to combine traditional methods of processing raw materials with some new technological solutions. As a result, an innovative product with various combinations of raw materials, as well as a high caloric content, can be obtained by this new technology. Aim and methods. The aim of the study is to substantiate and develop the technology of chocolate covered multi layered chips. Organoleptic research methods, the method of expert evaluations and the calculation method for determining quality and quantity indicators of chips are used to achieve the set purpose. Results. The organoleptic properties of chocolate covered multi layered chips are studied. It is obtained that chips have different shapes and sizes. The color of the chips surface depends on the composition of glaze and raw materials. Chips have a faint smell of chocolate and a sweet or sweet-sour taste. The inner layers of chips do not have a crispy and brittle consistency. In this research, some means of chips value quality indicators are calculated, their nutritional and energetical value is determined. Conclusions and discussion. It is obvious that adding berry powder to chocolate glaze improves taste properties of chips, the color of their surface and look in total. Chocolate covering of chips makes it possible to high their caloric content. The compositions of chips containing apple and berry powder have the highest values of quality, and the compositions of chips containing carrot and zucchini have the lowest ones. The scientific novelty of obtained results lies in the production technology elaboration of chocolate covered multi layered chips. The practical significance of the study results can be used in the expansion of chips assortment.

Elemental Comparison of Bones of Red Sokoto (Capra Hiracus) and West African Dwarf (Capra Aeagurus) Goats for Production of Glazes

Elemental characterization of glaze materials has not been of scholarly concern, especially in Nigeria where studies have also excluded animal by-products for glaze derivation and glaze modeling. This study therefore elementally examined ashes of bones of Capra hiracus (Red Sokoto Goats) and Capra aeagurus (West African Dwarf Goats) and produced glazes with them with a view to providing scientific modeling of the glazes. Raw bone samples of each animal were separately collected processed into ashes and analysed using particle induce X-ray emission (PIXE) and Rutherford Backscattering spectroscopic (RBS) techniques. Thirteen elements Magnesium, Aluminum, Silicon, Cholrine, Phosphorus, Potassium, Calcium, Titanium, Copper, Zinc, Lead and Iron (Mg, Al, Si, Cl, P, K, Ca, Ti, Cu, Zn, Pb and Fe) were determined and based on which the ashes of each sample with adobe clay, whiting, borax and soda ash were successfully modeled into five glaze batches, applied on bisque wares and fired up to 1150 0C in a down-draught kiln. Undiluted ash samples gave white and off-white colours. Their mixtures with other materials gave sienna and brown-ochre colours with opaque effect. In other words, the final glaze effects of the ashes were opaque. Visually, WAD combination was most successful, though with pocket of crazing, crawling and peeling off hosts. Conclusively, it is the hope of this article, that its finding will provoke further studies on comparative examination of animal by-products for glaze formulation, theorization and practical application.

Effect of Two Brands of Glaze Material on the Flexural Strength and Probability of Failure of High Translucent Monolithic Zirconia.

(1) Background: The effect of glazing on the mechanical properties of monolithic high translucent zirconia is not well reported. Therefore, the purpose of this study was to evaluate the effect of glazing on the flexural strength of high translucent zirconia; (2) Methods: Ninety specimens were prepared from second-generation 3Y-TZP high translucent blocks and divided into three groups. Glaze materials were applied on one surface of the specimen and subjected to a four-point bending test and flexural stress and flexural displacement values were derived. Descriptive fractographic analysis of surfaces was conducted to observe the point of failure and fracture pattern.; (3) Results: Control-nonglazed (647.17, 1σ = 74.71 MPa) presented higher flexural strength values compared to glaze I (541.20, 1σ = 82.91 MPa) and glaze II (581.10, 1σ = 59.41 MPa). Characteristic strength (σƟ) from Weibull analysis also observed higher (660.67 MPa) values for the control specimens. Confocal microscopy revealed that glazed surfaces were much rougher than control surfaces. Descriptive fractographic analysis revealed that there was no correlation between the point of failure initiation and flexural strength; (4) Conclusions: The test results demonstrated that glazing significantly decreased the flexural strength and flexural displacement of the zirconia specimens.

Application of calcium isotopes to the study of calcareous materials on Chinese glaze: A new methodological approach

AbstractIn this work, we propose an innovative application of the calcium isotope technique for the study of calcareous materials in Chinese glazes, supported by simulation experiments. The δ44/42Ca values have been determined for limestone, plant ash and glazed ceramic samples collected from the Ru kiln in Henan Province, the Lauding kiln in Hangzhou city, Zhejiang Province, and Jingdezhen in Jiangxi Province. The results show that the δ44/42Ca values in limestone in Henan and Zhejiang are all between 0.15‰ and 0.41‰, whereas the δ44/42Ca values of plant ash from the Ru and Laohudong kilns are all between −0.23‰ and −0.04‰. This means that the calcium isotope technique can effectively identify whether calcium levels in the glazes were supplied by plant ash or by limestone materials. More importantly, the calcium isotope technique can evaluate the proportions of plant ash and limestone if the local glaze materials have been studied thoroughly. According to the calcium isotope ratios established for this study, it is speculated that for the Jingdezhen kilns plant ash was used from the Late Tang to Five Dynasties, and limestone and plant ash were used for glazes in the Song and Yuan Dynasties. The calcium isotope technique can therefore offer an approach to identifying both the calcareous materials and the origins of ancient Chinese glazes, and provides a potentially powerful tool in their interpretation.

Effect of temperature and composition on rheological behaviour and sagging capacity of glaze materials for foods

In this work, the effect of temperature and composition on rheological behaviour and sagging capacity of glaze materials used for food coating applications was studied. Full-fat and low-fat formulations with 0, 3, 6, and 9% of vegetable fat or microparticulated whey protein as fat replacer were prepared. Dynamic and rotational rheometry was performed at 20, 30, 40, and 50 °C. Viscoelastic behaviour was analysed through phase angle, elastic modulus, and viscous modulus. In order to describe the flow behaviour, a concentration-temperature superposition technique was used with the Carreau-Yasuda, Krieger-Dougherty, and Williams-Landel-Ferry models. The theoretical evaluation of the sagging capacity, considered as a possible flow defect that alters the film homogeneity, was carried out. The characteristic viscosity that influences this phenomenon was calculated by estimating the theoretical average film thickness (using a mechanistic mathematical model previously published) and the gravitational shear stress of glaze materials. The obtained results have shown that formulations behaved as viscoelastic fluids as vegetable fat and microparticulated whey protein content increased and temperature decreased. This phenomenon was partially explained by the independence of elastic modulus with temperature, indicating that glaze materials are near the transition region between glassy and rubbery state. Flow curves could be described by the Carreau-Yasuda model; master curves of apparent viscosity data superimposed at different temperatures and compositions were achieved. Formulations with the same values of average film thickness (but higher values of sagging viscosity) could be obtained, indicating less probability for the sagging phenomenon to occur in those samples.

The Effect of TiO2 in Ceramic Product Glaze on the Photodegradation of Methylene Blue

Glaze is a coating on the surface of ceramic products such as tiles, sanitary ware and tableware. One of the functions of the glaze is to protect ceramic products from harmful chemicals such as dyes. For this purpose, the glaze material is added with other additives such as TiO 2 which is a photocatalyst. n this study, silica sand and commercial glaze 107 with a ratio of 1: 1 were used as the main raw material for glaze with the addition of 0-5% titanium dioxide powder. The raw material for the glaze is wet ground in an alumina potmill for 24 hours. The results of these mills, dried in an oven at a temperature of 100 o C. The dried glaze contains silica as a-quartz and anatase TiO 2 . The percentage of decolorization (photodegradation) of the glaze to the methylene blue dye after 4 hours of UV exposure was carried out by measuring the absorption of non-degraded methylene blue using a UV-Vis spectrophotometer at a wavelength of 664 nm. Glaze without the addition of TiO 2 showed a percent decolorization (photodegradation) of methylene blue of 71.55% which occurred mainly through the adsorption reaction of methylene blue by silica which is mostly contained in the glaze. The optimum value of percent decolorization is 88.49% obtained for glaze materials with the addition of 2% TiO 2 . The addition of TiO 2 which exceeds the optimum value, causes a decrease in the percentage of decolorization (photodegradation) due to TiO2 2 aggregation on the surface of the silica adsorbent.

The effect of acetic acid extraction time on the dissolution of lead and cadmium in ceramic tiles

With the improvement of people's living standard, the glazed tiles will be decorated with some colored glaze materials in order to increase strength and surface decoration effect, and these ceramic tiles containing lead and cadmium will be dissolved out under the action of acid. The dissolved lead and cadmium and other heavy metals after inhalation will affect the human liver, nervous system, hematopoiesis, and even paralysis. The Influence of detection mechanism and detection time on the results is discussed in this paper.

Evaluation of surface roughness, hardness and elastic modulus of nanoparticle containing light-polymerized denture glaze materials

Statement of problemThe surface hardness and roughness of different glaze materials for denture base acrylic resins have not been well reported. PurposeThe purpose of the study was to measure the surfaces hardness, elastic modulus and surface roughness of 5 different light-polymerized glaze materials for poly methyl methacrylate (PMMA) denture base materials. Material and methodsA total of 210 PMMA resin specimens (10 × 5 × 2 mm) were prepared (30 per group); control group was untreated, group 1 was surface treated with conventional pumice and high shine paste; group 2 to 6 specimens were glaze coated with different commercially available denture glaze materials. 20 specimens out of 30 underwent thermocycling to simulate 6 months and 12 months in vivo. Nanoindentation was performed to measure the surface hardness and elastic modulus. Surface roughness was quantitatively analysed using surface metrology software and qualitatively analysed under scanning electron microscope (SEM). Collected data was statistically analysed using SPSS version 24. ResultsThe mean surface hardness of tested specimens ranged from 0.33 ±0.09 GPa to 0.68 ±0.10 GPa. Specimens coated with Optiglaze produced statistically higher surface hardness compared to other groups (P< 0.01). Aging of 6 months and 12 months was found to have no statistical significance for all groups’ surface hardness values. For elastic modulus, specimens coated with Nanovarnish produced statistically higher values compared to other groups (P= 0.03). Thermocycling showed no influence on the elastic modulus of specimens. The mean surface roughness of all groups ranged from 0.16 ±0.01 to 0.30 ±0.02 μm with no statistical significance between groups (P= 0.67). However, under SEM analysis, surfaces showed increased roughness over time. ConclusionsStatistically significant differences in surface hardness and elastic modulus were found among the different types of surface coated denture acrylic resins. Silica-nanoparticle containing surface coatings produced the highest surface hardness and elastic modulus, however there was no statistical significance found in aging for 6 and 12 months. Contrary to expectations, the surface roughness did not have a significant increase in all groups over time, despite changes observed under SEM. Clinical implicationsThis study will contribute to our understanding of surface glazed PMMA acrylic resin denture materials and how it improves the surface strength. This research can help dental clinicians and technicians select the most effective polishing and coating material for the dentures.

An impact of the molar ratio of Na2O/K2O on nanomechanical properties of glaze materials containing zirconium oxide

In this paper the nanomechanical properties of three groups of glass-ceramic materials were measured. The materials designated from the multicomponent system: SiO2-Al2O3-CaO-MgO-Na2O-K2O and the difference between them was the molar ratio of sodium oxide to potassium oxide, equal to, respectively 5.45; 1.19; and 0.77. Zirconium oxide was added to those materials, in three different amounts (1.5; 3; 6 wt%). The obtained materials were characterized by the XRD method. The materials were also observed by means of a scanning electron microscope. The chemical compositions of amorphous and crystalline phases were analyzed by the EDS measurements. It has been discovered that the amorphous phase contains small amounts of zirconium cations, which positively affect its mechanical properties as confirmed by the results of a nanomechanical study. In addition, the presence of zirconium silicate and zirconium oxides in the phase composition improves mechanical properties. It was also shown that the molar ratio of alkali oxides (sodium oxide to potassium oxide) influences the amount of crystalline phase, i.e. mainly zirconium silicate. Sodium oxide, in contrast to potassium oxide, promotes the formation of more crystals in the analyzed materials and improves nanomechanical properties.

Sintering-Induced Nucleation and Growth of Noble Metal Nanoparticles for Plasmonic Resonance Ceramic Color

This study demonstrates the formation of nanoparticles (NPs) from metal salts within ceramic glazes, such that the use of this colorant technology is more accessible to artisans, employs less metal content, is less environmentally harmful, and allows for the use of traditional kilns. Gold NPs have been demonstrated to possess a specific, low material loading use as a ceramic glaze colorant via plasmon resonance. Pre-synthesized gold NPs that are added to ceramic glazes have been found to significantly change in size after firing in both reductive and oxidative atmospheres, but still maintain some size relationships and color properties. Unfortunately, it is not viable for the art community to fabricate and employ gold NP systems with high precision in a studio setting; however, the use of noble metal salts or metal oxides are realistic. To that end, this work investigates spontaneous gold and silver NP synthesis by the firing-induced development of NPs from metallic salts included within the glaze materials. Glaze samples with gold and silver salts are fired in reductive and oxidative environments, yielding a range of surface plasmon coloring effects for ceramic coloring. Additionally, the use of gold NP waste (precipitated Au NPs waste) was added to wet ceramic glazes to investigate firing effects on NPs precipitate and potential use as an alternative colorant. Sintering-induced NP nucleation and growth was observed after firing in both oxidation and reduction environments, although to differing degrees. The direct noble metal salt application process eliminates the need for preliminary gold NP synthesis, thus allowing for more practical and environmentally friendly methods in creating plasmonic resonance ceramic coloring, potentially reflective of the processes employed in ancient nanoparticle glasses.

A multi-size study of gold nanoparticle degradation and reformation in ceramic glazes

Most traditional ceramic glazes employ high amounts of transition metal colorants that are toxic to the environment and can cause health issues in humans through surface leaching. Gold nanoparticles (Au-NPs) have been found to be environmentally friendly and non-toxic alternative metal colorant in ceramic glazes. The plasmon band observed with Au-NPs can result in vibrant solutions by manipulating NP size, shape, and concentration; however, the effects of traditional firing in both reductive and oxidative kilns on Au-NPs are poorly understood. Aside from ancient art processes whose mechanisms have not been fully explored, the use of Au-NPs as suspended ceramic glaze colorants remains somewhat unexplored. Au-NPs have been previously reported to diminish in size during sintering and possess significant differences in concentration with respect to reduction and oxidation firing atmospheres. As a means of studying possible degradation/renucleation processes within the glaze during firing, a systematic study introducing different diameter Au-NPs into the glaze materials was conducted with transmission electron microscopy and reflectance spectroscopy used to probe possible mechanisms which showed changes to Au-NP diameter and color intensity, making this work applicable to industry and art current practices.

Fabrication and Testing of Solar Heat Collector by using alternative Absorber and Glaze Materials

Fabrication and Testing of Solar Heat Collector by using alternative Absorber and Glaze Materials

Influence of Industrial Solid Waste on the Chemical and Mechanical Properties of Traditional Glaze-Ceramics

New glaze compositions were synthesized from combinations of ceramic glaze and cement kiln dust. The products show very good chemical resistance to acid and alkaline corrosion, with no visual changes on the surfaces of the samples. This resistance can be attributed to the very well balanced composition of wastes and commercial ceramic glaze materials. Corrosion data reveal the results of mass loss either at 25 ℃ or 100 ℃. The mass loss is very low, showing that it is possible to develop glazes with excellent chemical resistance to strong acid and alkaline solutions corrosion starting from different concentrations of cement kiln dust associated with commercial ceramic glaze materials. The IR spectra of the prepared samples show characteristic bands related to the vibrations of triangular and tetrahedral borate and tetrahedral silicate groups together with metal-oxide groups. The surface hardness data of the glazes determined by Mohs are found to be 5–6 at early immersion times up to ∼9 days, but there is obvious deterioration beyond 9 days. The results point out that it possible to deepen the understanding of the mechanisms of elements released through the chemical attack and their implications on microstructural and mechanical degradation of the working surface of glazed ceramic tiles.

Effects of three different bleaching agents on microhardness and roughness of composite sample surfaces finished with different polishing techniques.

BackgroundThe aim of this study was to evaluate effects of different polishing methods and whitening agents on surface hardness and roughness of nano-hybrid composite resin. Material and MethodsIn total, one hundred twenty disc-shaped specimens were prepared to nano-hybrid composite (Charisma Diamond). 60 samples were used for microhardness measurements and the others were used for the evaluation of surface roughness. Samples were divided randomly into two subgroups (n = 30 each). In first group a low-viscosity liquid polishing agent (Biscover LV) was applied. In the second group, nothing was applied. All the samples were stored in distilled water at 37°C for 24 h. After initial measurements were completed, samples were divided randomly into three subgroups for bleaching application. 10% carbamide peroxide (Opalescence PF), 45% carbamide peroxide (Opalescence PF Quick), 38% hydrogen peroxide (Opalescence Boost) was applied. Then microhardness and surface roughness measurements of samples were repeated and data were recorded as final values for each sample.ResultsWhen the polishing techniques were compared, no signicant difference was observed in surface hardness and roughness. When the bleaching agents were compared, the 10% carbamide peroxide and 38% hydrogen peroxide containing bleaching agent groups showed statistically significant differences between pre- and post-procedure hardness values (p<0.05).ConclusionsOffice-type bleaching agent containing CP was observed to be more secure for composite resins than other bleaching agents. No negative effect of glaze materials on the protection of surface roughness and hardness of composite resin was observed. Key words:Composite resin, bleaching, surface hardness, surface roughness.