Surface Roughness Of Zirconia Research Articles

Evaluation of the Surface Roughness and Color Stability of Two Types of Milled Zirconia Before and After Immersion in Alcoholic Beverages: An In Vitro Study.

Objective This study aims to evaluate the effects of immersion in alcoholic beverages on the surface roughness and color stability of two types of milled zirconia. Materials and methods The sample size included 60 cuboid-shaped samples of two types of zirconia (Z1 and Z2), 30 in each group. Zirconia was milled and sintered at 1,500°C for eight hours. The samples were immersed in artificial saliva (control), red wine, and whiskey three times a day over a 30-day period. After each post-immersion cycle, samples were cleaned ultrasonically. Surface roughness and color parameters were measured using an atomic force microscope (AFM) and spectrophotometer before and after immersion. The collected data was organized into tables, and statistical analysis was conducted using the Statistical Package for the Social Sciences (SPSS) version 27 software (IBM SPSS Statistics, Armonk, NY). For surface roughness, a paired t-test was conducted, while for color change, one-way analysis of variance (ANOVA) andTukey's honestly significant difference (HSD) tests were done. Results The mean values of pre- and post-immersion values reveal that whiskey causes the highest difference in surface roughness for Z1 (137.09 nm) and Z2 (86.15 nm) groups, while red wine causes maximum discoloration in both Z1 (2.41) and Z2 (1.94) groups. The paired t-test revealed significant surface roughness changes in Z1with artificial saliva and red wine, while whiskey (p<0.05), although showing changes, lacked statistical significance (p>0.05). The whiskey group demonstrated a moderate linear association (0.599) between pre- and post-immersion values. For Z2, artificial saliva, red wine, and whiskey (p<0.05) induced statistically significant surface roughness alterations. ANOVA tests indicated significant color changes post-immersion in all three subgroups of Z1 and Z2 (p<0.05 for both). Tukey's HSD test showed significant differences between artificial saliva and red wine (p<0.05), as well as artificial saliva and whiskey (p<0.05) in Z1 and Z2. However, no significant difference was found between red wine and whiskey in both Z1 and Z2 groups (p>0.05). Conclusion Whiskey, red wine, and artificial saliva increased zirconia's surface roughness. Alcoholic solutions altered zirconia's colorimetric parameters, with no significant differences among them.

Bonding Effectiveness of Veneering Ceramic to Zirconia after Different Grit-Blasting Treatments.

Objective: To determine the effect of grit-blasting before and after sintering on the surface roughness of zirconia and the micro-tensile bond strength of a pressable veneering ceramic to zirconia. Methods: Pre-sintered zirconia blocks (IPS e.max ZirCAD, Ivoclar) were divided into four test groups of three specimens each and a control group ('CTR'; no surface treatment). Pre-S-30, Pre-S-50, and Pre-S-110 were grit-blasted with 30-µm SiO2-coated Al2O3, 50-µm Al2O3 and 110-µm Al2O3 particles, respectively, before sintering. Post-S-30 was grit-blasted with 30-µm SiO2-coated Al2O3 after sintering. For each treatment, the surface roughness was measured (Ra, Perthometer M4P, Mahr Perthen). After sintering the zirconia blocks, a liner was applied and a pressable ceramic (IPS e.max ZirPress, Ivoclar) was heat-pressed. Sixteen microbars were obtained from each block and submitted to micro-tensile bond-strength (µTBS) testing. Data were analyzed with one-way ANOVA. Any correlation between Ra and µTBS was evaluated (Sperman test). Results: Grit-blasting before sintering with 110-µm Al2O3 (RaPre-S-110 = 3.4 ± 0.4 µm), 50-µm Al2O3 (RaPre-S-50 = 2.3 ± 0.5 µm), and 30-µm SiO2-coated Al2O3 (RaPre-S-30 = 1.2 ± 0.2 µm) resulted in significantly higher roughness than grit-blasting after sintering with 30-µm SiO2-coated Al2O3 (RaPost-S-30 = 0.5 ± 0.1 µm). The highest µTBS was measured when the sintered zirconia was grit-blasted with 30-μm SiO2-coated Al2O3 (µTBSPost-S-30 = 28.5 ± 12.6 MPa), which was significantly different from that of specimens that were grit-blasted before sintering (µTBSPre-S-30 = 21.8 ± 10.4; µTBSPre-S-50 = 24.1 ± 12.6; µTBSPre-S-110 = 26.4 ± 14.1) or were not grit-blasted (µTBSCTR = 20.2 ± 11.2). Conclusions: Grit-blasting zirconia before sintering enhanced the surface roughness proportionally to the particle size of the sand used. Grit-blasting with 30-µm SiO2-coated Al2O3 after sintering improved bonding of the veneering ceramic to zirconia. Clinical Significance: As grit-blasting with 30-µm SiO2-coated Al2O3 after sintering improved bonding of the veneering ceramic to zirconia, it may reduce veneering ceramic fractures/chipping.

Surface property changes observed in zirconia during etching with high-concentration hydrofluoric acid over various immersion times.

This study investigated the degree of phase transformation, surface roughness, and bond strength of zirconia immersed for various times in a 40% hydrofluoric acid (HF) solution. Non-etched sintered zirconia specimens were used as the control, while experimental groups were etched with a 40% HF solution for 5, 10, 20, 40, 80, 160 and 320 min. In each of the control and experimental groups, five specimens for X-ray diffraction analysis, four for surface morphology and surface roughness analysis, and ten for bonding strength measurement were used. As a result, the surface roughness of zirconia increased as the application time increased during the 40% HF etching, but the bond strength between zirconia and resin cement did not increase proportionally. The phase transformation from tetragonal to monoclinic also gradually increased with application time.

Morphologic Analysis of Zirconia Ceramics: Effect of Different Surface Treatments.

To investigate the effects of airborne-particle abrasion and nanosilica (nano-Si) infiltration treatment on the surface characteristics of dental zirconia. A total of 15 unsintered zirconia ceramic green bodies (10 × 10 × 3 mm) were divided into three groups (n = 5): Group C, no treatment after sintering; Group S, airborne-particle abrasion with 50-μm aluminum oxide particles after sintering; and Group N, infiltration of nano-Si followed by sintering and hydrofluoric acid (HF) etching. The zirconia disks' surface roughness was analyzed by atomic force microscopy (AFM). The surface morphology of the specimens was analyzed using scanning electron microscopy (SEM), and the chemical composition was analyzed by energy-dispersive x-ray (EDX). Data were statistically analyzed by the Kruskal-Wallis test (P < .05). Zirconia surface treatments by infiltration of nano-Si, sintering, and HF etching showed multiple changes in the surface features. The surface roughness of Groups C, S, and N were 0.88 ± 0.07 μm, 1.26 ± 0.10 μm, and 1.69 ± 0.15 μm, respectively. The surface roughness of Group N was significantly higher than that of Groups C and S (P < .05). EDX analysis showed peaks that corresponded to silica (Si) after infiltration with colloidal Si that disappeared following acid etching. Infiltrating nano-Si increases the surface roughness of zirconia. The formation of retentive nanopores on the surface potentially improves the zirconia-resin cement bonding strengths.

Effect of Low-Temperature Degradation, Ph-Cycling and Simulated Tooth Brushing on Surface Roughness, Topography, and Polish Retention of Yttrium-Stabilized Tetragonal Zirconia.

Surface roughness of zirconia is an important parameter that determines the success of zirconia restorations. When zirconia surfaces are left rough, higher susceptibility to hydrothermal aging, plaque accumulation and color changes would occur. Therefore, polish retention of these restorations is considered as a challenge. The purpose of this in vitro study was to determine the effect of hydrothermal degradation, pH- cycling, and simulated tooth brushing on surface roughness, topography, and polish retention of an yttrium-stabilized monolithic zirconia. In this experimental study, 64 specimens of yttria-stabilized tetragonal zirconium oxide (20×4×2mm) were prepared (ZirKonzahn, Steger, Ahrntal). The specimens were wet- polished (standard polishing), and divided into 8 groups (n=8). Four control groups were assessed in non-aged condition while in 4 experimental groups the artificially ageing was done. Different finishing and polishing procedures were performed in 8 groups. The surface roughness values including mean surface roughness (Ra) and mean height of surface roughness (Rz) was measured by a profilometer. The results were analyzed using two-way ANOVA and Tukey's HSD test (α=0.05). One representative specimen of each group was inspected under a scanning electron microscope (SEM) for assessment of surface topography. The effects of surface treatments on Ra (p<.001) and Rz (p<.001) parameters were significant. Ageing had no significant effect on Ra (p=.086) and Rz (p=.067) values. Maximum Ra and Rz parameters were recorded following grinding (p<.001) and minimum values were recorded after glazing, which were significantly lower than the values in grinding group (p<.001). Polishing and glazing diminished the surface roughness (Ra) of ground zirconia similarly (p=.995). Aging had no significant effect on surface roughness of zirconia, irrespective of surface treatment type. Grinding yielded maximum surface roughness. Intra oral polishing yielded a surface roughness comparable to standard polishing and glazing.

The Effect of 1% Povidone Iodine Mouthwash on The Surface Roughness of Zirconia Reinforced Glass Ionomer Cement

&#x0D; Introduction: Zirconia reinforced glass ionomer cement is a new generation glass ionomer cement restoration material with the addition of zirconia nanoparticles that is equivalent in strength to amalgam while maintaining ability to release fluoride like conventional glass ionomer cements. Surface roughness can be affected by various factors including the use of mouthwash. Mouthwash that is commonly used during pandemic COVID-19 is 1% povidone iodine. Previous study stated that povidone iodine mouthwash contains alcohol and acidic pH which can decrease the hardness of composite resins. Objective: To determine the effect of 1% povidone iodine mouthwash on the surface roughness of zirconia reinforced glass ionomer cement. Methods: This was a true experimental laboratory research with a pre test and post test control group design. The research samples consisted of 36 samples of zirconia reinforced glass ionomer cement with diameter of 10 mm and height of 2 mm. The samples were divided into two groups: the control group which was immersed in artificial saliva and the treatment group which was immersed in 1% povidone iodine mouthwash for 24 hours. Surface roughness was measured using a surface roughness tester. Data were analyzed using Paired Sample T-Test and Independent Sample T-Test. Results: Paired Sample T-test results showed no significant difference in the surface roughness of the control group between before and after immersion with p value = 0,074 (p&gt;0,05) and a significant difference in the surface roughness of the treatment group between before and after immersion with p value = 0,000 (p&lt;0,05). Independent Sample T-Test results showed significant difference in the surface roughness between the control group and the treatment group with p value = 0,000 (p &lt;0.05). Conclusion: 1% povidone iodine mouthwash has an effect on increasing the surface roughness of zirconia reinforced glass ionomer cement.

Effect of Different Decontamination Methods on Fracture Resistance, Microstructure, and Surface Roughness of Zirconia Restorations-In Vitro Study.

This study aimed to evaluate the effect of seven different decontamination methods (water, ZirCleanTM, 37% phosphoric acid, 9.5% hydrofluoric acid, Al2O3 sandblasting, low-speed dental stone, and high-speed dental stone) on the fracture resistance, microstructure, and surface roughness of monolithic and multilayered zirconia. The as-received and sandblasted zirconia was used as a control. One-way ANOVA and t-test were performed. As-received monolithic zirconia was stronger (856 ± 94 MPa) than multilayered zirconia (348.4 ± 63 MPa). Only phosphoric acid (865 ± 141 MPa) and low-speed dental stone (959 ± 116 MPa) significantly increased the flexural strength of sandblasted monolithic zirconia (854 ± 99 MPa), but all tested decontamination methods except phosphoric acid (307 ± 57 MPa) and Al2O3 (322 ± 69 MPa) significantly increased the flexural strength of sandblasted multilayered zirconia (325 ± 74 MPa). Different decontamination methods did not significantly affect the flexural modulus, but introduced irregularities in the crystal as well as deep surface flaws in both types of zirconia. The surface of sandblasted monolithic zirconia is more resistant to change than multilayered zirconia. Among different decontamination methods, a low-speed dental stone could be beneficial as it significantly increased the surface roughness and fracture resistance of both types of zirconia.

Evaluation of Zirconia Surface Roughness after Different Surface Treatment with Sandblasting, Hydrofluoric Acid Etching, and Combination Treatment

Zirconia is one of the materials used in prosthetic restoration because of its better physical, mechanical, chemical, and biological properties. The surface treatment for zirconia can be mechanical, with grinding, sandblasting, and laser or chemically, with silane and etching. The combination of chemical and mechanical surface treatment can increase the surface roughness so that the bonding with the resin cement also increases. The study aims to examine the zirconia surface roughness after different surface treatments. This study used 25 zirconia samples in 10x10x2 mm square-shaped, divided into five groups. Group 1 treats sandblasting as a control. Group 2 sandblasting then etching with 9.5% hydrofluoric acid at 25°C for 60 minutes. Group 3 sandblasting then etching with 9.5% hydrofluoric acid at 100°C for 1 minute. Group 4 etching with 9.5% hydrofluoric acid at 25°C for 60 minutes. Group 5 etching with 9.5% hydrofluoric acid at 1000C for 1 minute. The samples were cleaned with an ultrasonic cleaner and tested using a profilometer. The data test by using the ANOVA test and T-test. The highest surface roughness was the combination of sandblasting with 9.5% hydrofluoric acid etching at 25°C for 60 minutes. The lowest was 9.5% hydrofluoric acid etching at 100°C for 1 minute. ANOVA statistical analysis with a p-value &lt;0.05 ((8.4051 x 10-12) indicates that the test was significant. The result of this study was the combination of surface treatments resulted in higher surface roughness. Duration of the etching time affected the increase of zirconia surface roughness.

Effect of Sandblasting with Fluorapatite Glass-ceramic Powder and Chemical Primers/Adhesives on Shear Bond Strength of Indirect Repairing Composite to Zirconia.

To investigate the effect of sandblasting with fluorapatite glass-ceramic (FGC) powder on zirconia surface roughness, crystallinity, and shear bond strength (SBS) of indirect repairing composite to zirconia using different primers/adhesives. Zirconia blocks were treated as follows: no treatment (control group), blasting with 30-μm silica-coated alumina (CoJet group), and blasting with FGC powder (FGC group). The surface topography, silica content, roughness, and crystallinity of treated zirconia surfaces were analyzed by a scanning electron microscope (SEM), energy dispersive spectroscopy (EDS), an optical profilometer, and X-ray diffraction (XRD), respectively. Four primers/adhesives (Monobond Plus, Calibra Silane, Futurabond M+, and Scotchbond Universal) were compared to bond precured resin composite to zirconia groups using Multilink Automix resin cement. Bonded specimens were thermocycled for 10,000 cycles and tested in SBS and the modes of failure were recorded. The effect of different surface treatments and primers/adhesives on SBS results were statistically analyzed using two-way ANOVA and Bonferroni post-hoc tests (α=0.05). Both CoJet and FGC groups showed rough surfaces with a higher content of silica in FGC, but less monoclinic crystals, compared to the CoJet group. The highest mean SBS was found in the FGC group treated with Monobond Plus compared to CoJet and Control groups. Adhesive failure was predominant in control groups, while combined failure was found in the CoJet and FGC groups regardless of the primers/adhesives employed. Sandblasting zirconia with FGC powder increased SBS of resin composite to zirconia with lower monoclinic phase transformation compared to CoJet sand. Monobond Plus reported the highest means of SBS values compared to other primers/adhesives.

Polycrystalline particulates synthesized on zirconia for enhanced bioactivity: An in vitro study.

Zirconia is a promising material for dental implant with its excellent biocompatibility, good mechanical properties, and esthetic effect similar to natural teeth. To improve the bioactivity and osteogenic properties of zirconia, pre-sintered zirconia discs were divided into C, T3 , T5 , and T7 group. Group C was as control. T3 , T5 , and T7 groups were soaked in hydrofluoric acid (HF) for 30, 50, and 70 s, respectively. Then, they were placed into CaCl2 solution and heated in NaOH solution. After sintering, the samples were characterized by scanning electron microscopy, energy dispersive spectrometry, and X-ray diffraction, which confirmed the ZrO2 polycrystalline particulates in situ synthesized on the treated sample discs. The surface roughness of the treated samples was increased with the prolonged of acid treatment time (p < .05), while the three-point bending strength did not decrease significantly (p > .05). MC3T3-E1 cells were cultured on zirconia discs to evaluate the bioactivity and osteogenic effect of modified zirconia. The living&dead fluorescence staining and CCK-8 assay showed that the specimens were non-toxic and significantly promoted cell proliferation. In addition, the cell proliferation was enhanced with the increase of zirconia surface roughness. Polycrystalline particles modified zirconia were beneficial to cell spreading. After osteogenic induction, MC3T3-E1 cells inoculated on modified zirconia exhibited higher alkaline phosphatase activity, mineralization activity and up-regulated osteogenesis-related gene expression. Above all, in situ synthesized polycrystalline particulates significantly improve the biological activity of zirconia, which will promote the widespread application of zirconia implants.

Effects of Different Polishing Systems on Surface Roughness and Crystal Structure of Zirconia.

Objective Intraoral polishing systems have become an alternative method for reglazing, which is important to prevent or minimize rapid wear of the opposing teeth. To assess the influence of different polishing systems and duration on surface roughness and crystal structure of zirconia was compared, contributing to the preparation and effect improvement of clinical zirconia restorations. Methods Forty-eight zirconia specimens with equal size were fabricated by cutting and sintering zirconia discs. Then X-ray diffractometer (XRD) was adopted for examination of the specimens. Six specimens were selected as the grinding-polishing group (GL) after polishing, grinding, and glazing. Then six specimens were randomly selected from the remaining specimens as the grinding-unpolished group (GR) after surface conditioning by dental diamond burs. Subsequently, based on different polishing systems and duration, the rest of specimens were divided into following groups (n = 6): Youdent-20s group (Y20), Youdent-40s group (Y40), Youdent-60s group (Y60), Toboom-20s group (T20), Toboom-40s group (T40), and Toboom-60s group (T60). Additionally, a contour graph was applied for assessing the surface roughness of zirconia, scanning electron microscope (SEM) for observing surface topography, and X-ray diffraction analysis (XRD) for determining crystal structure of zirconia. Results The GR group had the highest roughness, and the roughness of the specimens polished for 20 s with different polishing systems was significantly higher than those polished for 40 s and 60 s with the same polishing systems. There were no significant difference between the Y20 and T20 groups, while the roughness of the specimens in both Y40 and Y60 groups was significantly higher than that of the T40 and T60 groups. And with the increasing polishing duration, the surface morphology of the specimen was gradually smooth and the morphology was gradually regular. Besides, the surface scratches of the T group were shallower than that of the Y group at the same polishing duration. The peak value of XRD profile of the specimen after grinding and polishing process was consistent with the baseline pattern of that the original specimen. Conclusion Glazing can reduce the surface roughness of the specimens. Besides, the polishing effect of Toboom (TOB) system (polishing duration = 60 s) is the best. And different polishing durations of TOB system have no significant effect on the crystal surface structure of the specimen.

Effects of ytterbium laser surface treatment on the bonding of two resin cements to zirconia

Monolithic zirconia crowns bonded to zirconia abutments have become more commonly used in the construction of cement-retained implant superstructures. The present study aimed to examine the effects of laser surface treatments on the bond strength of two resin cements to zirconia. Three types of surfaces were examined: untreated, alumina blasted, and ytterbium laser treated; and two types of resin cements: 4-META/MMA-TBB resin cement and composite resin cement. Half of the specimens were subjected to a thermocycling process. Subsequently, a shear bond test was carried out. In addition, surface roughness was measured for each surface type. The results showed that laser treatment increased zirconia surface roughness and that laser treatment significantly increased shear bond strength after the thermocycling of both cement types compared to no treatment. Our experimental results suggested that ytterbium laser surface treatment of zirconia increased the bond strength of resin cements.

Evaluation of the Bonding Strength between Various Dental Zirconia Models and Human Teeth for Dental Posts through In Vitro Aging Tests

In dentistry, root canal treatment reduces support of the tooth, making it necessary to insert a cylindrical body into the treated tooth to strengthen the crown. In the past, metal or fiberglass was often used. However, metal is too different in color from teeth, so the esthetics are poor, and fiberglass is not as strong as metal. Therefore, an alternative is zirconia, which has the characteristics of high light transmittance, esthetics, good biocompatibility, and high breaking strength. The surface morphology and composition of zirconia ceramics are the key to their bond strength with teeth. Therefore, in this study, the surface characteristics of different brands of zirconia commonly used in clinical practice were evaluated in terms of their surface morphology and surface elements. The surface was modified by sandblasting, and its effect on the bonding strength was discussed. Finally, the stability of the material was evaluated through artificial aging. The results showed that the surface roughness of the zirconia specimens increased after sandblasting, whereas the surface microhardness decreased. The shear test results showed that the 3D shape of the zirconia surface could help improve the bonding strength. The bonding strength of DeguDent increased the most after sandblasting. After 20,000 cycles of aging treatment, the shear strength of each specimen decreased. Field emission scanning electron microscopy results showed that the adhesive remained intact on the surface of zirconia, indicating that adhesion failure occurred between the adhesive and the teeth. This confirms that sandblasting can improve the bonding strength of zirconia. Based on the results obtained, it was concluded that the surface roughness of zirconia is the main factor affecting the bond strength.

Surface Roughness Assessment of the Sandblasted and Acid- Etched Zirconia Ceramic

Aims: To evaluate the effect of sandblasting with Al2O3 particle and 30% citric acid etching on the roughness of zirconia ceramic. Materials and Methods: Thirty disks were prepared from partial sintered zirconia (IPS e.max ZirCAD MT blank disk, Ivoclar Vivadent; Schaan, Liechtenstein). Specimens were assigned randomly into three groups based on surface treatment techniques (n=10). Group I zirconia surface was left without surface treatment (control). Group II specimens were subjected to sandblasting with 110 µm Aluminum oxide particles (Al2O3) while the group III surface was treated with citric acid solution 30% for 10 minutes. The surface roughness of the zirconia was investigated using a profilometer. Data were analyzed with one-way ANOVA and Duncan’s tests at 5% level of significance. Results: Sandblasting with AL2O3 110µm significantly increased the surface roughness value of the zirconia surface. Chemical treatment with 30% citric acid did not exhibit any significant changes in comparison to the control group. Conclusions: Sandblasting with AL2O3 increased zirconia surface roughness but acid etching has no effect.

Comparative evaluation of micro-tensile bond strength between zirconia core and all-ceramic layering with different surface treatments: an in vitrostudy

Background: The quest for newer and stronger materials for replacing teeth has resulted in Zirconium oxide's introduction, which possesses excellent mechanical strength and toughness. However, uncertainty exists in the relationship between its bond strength and surface treatment method adopted and the mode of failure at the interface. Aim - The study aimed to evaluate the comparison of micro-tensile bond strength between the zirconia core and all-ceramic layering with different surface treatments and analyse their failure mode by Scanning Electron Microscope (SEM). Materials and methods: Zirconia cores (Ceramill ZI 71 XS) were fabricated by CAD-CAM into discs with 5mm diameter and 3.5mm height. Then the cores were divided into four groups. Among which, Group-I was the control group, and the remaining are surface treated. Group-II specimens were treated with sandblasting, followed by acid etching; Group-III and Group-IV were treated with zirliner and glass beads, respectively. After that, the veneering material (IPS Empress, E.max Ceram Dentin) of 2×2 mm was adhered to the zirconia core and then kept in the ceramic furnace. The specimens were mounted on a Universal Testing Machine, and tensile stress is applied. The obtained data were subjected to One-way ANOVA and Tukey-HSD tests for statistical analyses. Results - The samples treated with sandblasting followed by acid etching showed more micro-tensile bond strength between core and veneer interface. Furthermore, the SEM study revealed a cohesive failure in Group-II, whereas, in Group-I and -III, there was an adhesive failure. Group-IV specimens exhibited a mixed failure. One-way ANOVA showed significant differences (p=0.001) within the groups. In posthoc analysis, Group-III showed significant differences with Groups -I, II, and IV. Conclusion: Increased surface roughness of zirconia obtained by sandblasting with aluminium oxide particles, when coupled along with chemical etching with hydrofluoric acid, enhanced the micro-tensile bond strength between the Y-TZP zirconia core and veneering ceramic.

Combined application of femtosecond laser and air-abrasion protocols to monolithic zirconia at different sintering stages: Effects on surface roughness and resin bond strength.

This study aimed to investigate the effects of femtosecond laser (Fs) and/or air-abrasion protocols on surface roughness (Ra) of zirconia and resin bond strength. Eighty zirconia samples were randomly divided into eight subgroups according to surface treatment protocols: Control (C), Air-abrasion before sintering (ABS), Air-abrasion after sintering (AAS), Air-abrasion before and after sintering (ABS + AAS), Fs laser before sintering (FBS), Fs laser before sintering + air-abrasion after sintering (FBS + AAS), Fs laser after sintering (FAS), and Fs laser after sintering + air-abrasion after sintering (FAS + AAS). Measurements of Ra values were obtained using a surface profilometer. Surface morphological properties were evaluated with scanning electron microscopy (SEM), and crystallographic changes were examined by X-Ray diffractometry (XRD). Self-adhesive resin cement was bonded to zirconia samples, and shear bond strength (SBS) tests were performed. The data were statistically analyzed by one-way ANOVA, followed by Tamhane tests. The control group displayed the lowest Ra and SBS values among all groups. The highest Ra and SBS values were found in the FBS and FBS + AAS groups. Air-abrasion applied before sintering significantly increased the Ra of specimens. FAS, FAS + AAS, and ABS + AAS groups exhibited higher SBS values than AAS and ABS (p < .05). Air-abrasion applied after Fs laser did not produce any significant change in the Ra and SBS compared to Fs laser alone (p > .05). Femtosecond laser application may be a promising method to enhance the surface roughness of zirconia and improve resin bond strength. Air-abrasion at pre- and post-sintered stages may also be a viable surface treatment option.

Glow Discharge Plasma Treatment on Zirconia Surface to Enhance Osteoblastic-Like Cell Differentiation and Antimicrobial Effects.

Peri-implantitis is the pathological condition of connective tissue inflammation and the progressive loss of supporting bone around dental implants. One of the primary causes of peri mucositis evolving into peri-implantitis is bacterial infection, including infection from Porphyromonas gingivalis. Enhancing the surface smoothness of implants helps to prevent P. gingivalis adhesion to the implant’s surface. Interaction analyses between bacteria and the surface roughness of zirconia (Zr) discs subjected to a glow discharge plasma (GDP) treatment compared with non-plasma-treated autoclaved control Zr discs were done. Examinations of the material prosperities revealed that the GDP-treated Zr group had a smoother surface for a better wettability. The GDP-treated Zr discs improved the proliferation of the osteoblast-like cells MG-63, and the osteoblastic differentiation was assessed through alkaline phosphatase detection and marker gene bone sialoprotein (Bsp) and osteocalcin (OC) induction. Scanning electron microscopy demonstrated a relatively low P. gingivalis adhesion on GDP-treated Zr disks, as well as lower colonization of P. gingivalis compared with the control. Our findings confirmed that the GDP treatment of Zr discs resulted in a significant reduction of P. gingivalis adhesion and growth, demonstrating a positive correlation between surface roughness and bacteria adhesion. Therefore, the GDP treatment of Zr dental implants can provide a method for reducing the risk of peri-implantitis.

Influence of the surface roughness of zirconia on the coefficient of static friction and retentive force of telescopic crowns

Influence of the surface roughness of zirconia on the coefficient of static friction and retentive force of telescopic crowns

A comparative study of the wear of dental alloys against monolithic zirconia

Statement of problemMaterials used for dental restorations should cause wear similar to that of natural teeth. Studies on the wear of dental alloys against monolithic zirconia are lacking. PurposeThe purpose of this in vitro study was to compare the wear of Co-Cr, gold, and Ni-Cr alloys against monolithic zirconia of different surface roughness. Material and methodsCylindrical monolithic zirconia specimens were prepared by a sintering process. Sintered zirconia was then polished to prepare 30 zirconia substrate specimens with a smooth surface (Ra<0.1 μm) and 30 with a rough surface (3.5 μm<Ra<4.5 μm). As antagonist specimens, 3 types of metal alloys (Co-Cr, gold, and Ni-Cr alloys) were used. Twenty cast crowns were prepared from each metal alloy in the shape of a maxillary premolar. For each alloy, 10 cast crowns were randomly selected to oppose the smooth-surface zirconia specimens and 10 to oppose the rough-surface zirconia specimens. A total of 6 wear test groups were formed. Wear tests were performed by using a mastication simulator at 240 000 mastication cycles. Wear on the antagonist specimens was measured by using a laser 3D scanner. After wear testing, antagonist and substrate specimens were inspected by using a scanning electron microscope (SEM). For statistical analysis of the data, the 2-way ANOVA and the Scheffé multiple comparison tests were used (α=.05). ResultsOf the 6 test groups, the gold alloy specimens opposed to rough-surface zirconia exhibited the most wear, while the Co-Cr alloy specimens opposed to smooth-surface zirconia exhibited the least wear (P<.05). Rough-surface monolithic zirconia caused significantly more wear of the metal alloy specimens than did smooth-surface monolithic zirconia (P<.01). ConclusionsIncreased surface roughness of monolithic zirconia was associated with increased wear of the opposing dental alloy. When monolithic zirconia surface roughness was increased, wear of dental alloys increased most for gold alloys, followed by Ni-Cr, and then Co-Cr alloys.

Synergistic reinforcement of surface modification on improving the bonding of veneering ceramics to zirconia

Veneering ceramics should be strongly bonded to zirconia core in order to achieve successfully long-term clinical practice. Indeed, to pursue the high zirconia core–veneering ceramic bonding is still a concerned issue. In this regard, this study was to treat zirconia surface using a 3 wt% Si3N4 solution in 4 M NaOH and to investigate the effect of soaking time (5, 10, and 20 days) on the surface properties of zirconia and shear bond strength between zirconia and veneering ceramics. The residual veneering ceramics on zirconia surfaces and failure modes were also examined after fracture. The results showed that the phase composition of zirconia before and after surface modification was not changed. The elemental mapping and depth profiling consistently revealed the soaking-time-dependent Si content on the zirconia surface. The surface roughness of zirconia was significantly (P < 0.05) increased with the increasing soaking time. When zirconia was treated for 10 days, the shear bond strength value of 27.4 MPa was significantly (P < 0.05) higher than the control (18.6 MPa), associated with greater remaining amounts of veneering ceramics on the zirconia surface. The failure mode of the treated zirconia was almost the mixed failure. On the basis of the data, surface modification using Si3N4 in NaOH solution for zirconia core could be a simple and effective method for enhancing the veneering ceramic–zirconia bonding.