Surface Conditioning Methods Research Articles

The shear bond strength of orthodontic brackets after surface conditioning of Zirconia, Ceramic and E. max models

The current study aims to evaluate the shear bond strength (SBS) of metal orthodontic brackets after surface conditioning by hydrofluoric acid (HF) and aluminum oxide air abrasion (Al2O3) and using two prime types and to determines the adhesive remnant index (ARI). We compared the bond strength of different types of models (full glazed zirconia, ceramic faced zirconia and E. max faced zirconia) with different surface conditioning methods for attaching metal orthodontic brackets. The study used 60 models for each material, divided into subgroups based on the type of prime material and surface preparation method. The bond strength was measured using a universal testing machine and the results were analyzed using statistical software. Shear bond strength of the Aluminum oxide was statistically (p<0.05) higher than the hydrofluoric acid and control groups in all groups (full glazed zirconia, ceramic faced zirconia and E. max faced zirconia). The Assure® Plus primer with Aluminum oxide surface treatment give rise to the highest shear bond strength than 3M™ Transbond™ XT, while there was no significant difference between Assure® Plus and 3M™ Transbond™ XT primer for both control and hydrofluoric acid groups. The highest shear bond strength was obtained with Aluminum oxide conditioning method for all types of ceramic materials used in this study.

Enamel Deproteinization or Sandblasting for Enamel Reconditioning Before Acid Etching to Enhance the Shear Bond Strength of Metallic Brackets in a Third Bonding: An In Vitro Study.

Enamel conditioning with 37% phosphoric acid is the most common technique during orthodontic bracket bonding procedures. However, due to the repeated de-bonding of the orthodontic brackets during treatment, other methods were needed to condition the enamel surface and increase the bond strength. This study aimed to compare the effect of conditioning the enamel surface by sandblasting with aluminum oxide particles or 5.25% sodium hypochlorite gel in combination with acid etching compared to acid etching alone on shear bond strength (SBS). One hundred eight extracted upper premolars were randomly divided into three groups according to the conditioning enamel surface method. After the first and second bonding of metal brackets, new metal brackets were bonded with a total-etching adhesive after enamel conditioning using different methods: acid etching only (37% phosphoric acid for 30 seconds) (AE group), sodium hypochlorite associated with acid etching (5.25% NaOCl gel for 60 seconds and then acid etching for 30 seconds) (NaOCl-AE group), and sandblasting associated with acid etching (sandblasting for five seconds and then acid etching for 30 seconds) (SB-AE group). The shear bond strengths of the brackets were tested with a universal testing machine. One-way analysis of variance (ANOVA) and Tukey's honestly significant difference (HSD) tests were used to detect significant differences in shear bond strength among groups at the third bonding. Repeated-measure ANOVA and Bonferroni's tests were used to detect significant differences in shear bond strength among the bonding attempts within each group. 5.25% sodium hypochlorite associated with the acid etching method produced significantly greater shear bond strength than sandblasting associated with acid etching and acid etching only methods at the third bonding (16.40 ± 5.80 MPa, 13.60.47 ± 6.40 MPa, and 9.90 ± 4.40 MPa, respectively; P < 0.001). However, there was no significant difference between the AE and SB-AE groups (P = 0.247). In addition, we found a significant decrease in the shear bond strength within each group after each bonding attempt. Conditioning the enamel surface with 5.25% sodium hypochlorite associated with acid etching produced greater bond strength than conditioning by sandblasting associated with acid etching and acid etching only at the third bonding. The bond strength of the metal bracket decreased with increasing bonding attempts, even with the application of enamel surface conditioning methods.

Pretreatment of Hybrid Ceramics Using Ho: YAG, Low-Level Laser Therapy Activated Malachite Green, and Non-Thermal Plasma on Surface Roughness, Bond Strength, and Color Change, SEM and EDX Analysis

The study aimed to assess the effects of different surface conditionings on hybrid ceramics (HBC). Hydrofluoric acid was combined with a silane (HFA+S), low-level laser therapy activated Malachite green (LLLT-MG), Ho: YAG laser, and non-thermal plasma (NTP) as surface conditioning methods for HBC. Eighty-four HBC discs were prepared and divided into four groups according to surface conditioning methods. The total number of samples (n = 21) for each group was further split into two for the non-thermocycling and thermocycling subgroups. After surface treatment, all samples were examined to study the effect of color change and surface roughness. The shear bond strength (SBS) test of HBC was performed on thermo-cycled samples. Statistical analysis using ANOVA with Tukey post hoc was performed to observe any significant difference among tested groups, p &gt; 0.05. The HFA+S and Ho: YAG surface-treated samples showed higher SBS than other surface-treated samples due to higher surface roughness. All surface conditioning methods, except NTP, induced noticeable color change, making them less suitable for aesthetical purposes in clinical settings. Overall, surface conditioning methods are critical in affecting shear bond strength through surface roughness and color change.

Effect of Different Conditioning Methods on Shear Bond Strength of Orthodontic Ceramic Brackets Bonded to Porcelain Ceramic Surface

The study aimed to investigate the shear bond strength (SBS) of orthodontic ceramic brackets bonded to porcelain ceramic surfaces that had undergone various conditioning methods. Materials and Methods: Forty ceramic discs were fabricated (vita vmk master®, zahnfabric, Germany) with a diameter of (4*10mm). Ceramic discs were divided into four groups (n = 10) according to ceramic surface conditioning methods, 37% phosphoric acid (PH), 9%hydrofluoric acid (HF), and surface conditioning with a fine diamond bur. Transbond XT light-cure composite was used to bond ceramic brackets. Before bonding, extra samples from each group were chosen to be examined using a scanning electron microscope (SEM) to determine the topography of the ceramic surface. The Shear Bond Strength data were evaluated using one-way analysis of variance (ANOVA) and Tukey HSD tests. Under an optical stereomicroscope, debond surfaces were examined. Results: Surface conditioning with a fine diamond bur + HF acid etching group produced the highest SBS (30.64 ± 7.28 MPa), and the lowest SBS was investigated in the PH acid etching group (14.75 ±3.32 MPa). Conclusions: Different conditioning methods affected the porcelain ceramic surface's shear bond strength (P &lt; 0.05). The highest SBS was found in the fine diamond bur_+ HF acid etching group; however, this had a deleterious effect on the ceramic surface after debonding.

The Effect of Femtosecond Laser Surface Patterns on the Effectiveness of Resin Composite to Zirconia Bonding.

This laboratory study aimed to evaluate the effect of different surface patterns using femtosecond laser treatment on the enclosed mold shear bond strength (EM-SBS) of resin composite to zirconia (ZrO2) surfaces and to contrast it with the widely used tribochemical silica coating (TBC) surface conditioning method. A set of fifteen rectangular ZrO2 blocks were randomly divided into five groups according to surface pretreatment: Control G0-no treatment; G1-TBC with silane application; G2-femtosecond laser irradiation with horizontal lines 30 µm apart; G3-femtosecond laser irradiation with horizontal lines 15 µm apart; and G4-femtosecond laser irradiation with cross lines 30 µm apart. The pretreated surfaces were characterized by a surface profilometer, tensiometer and scanning electron microscope. The EM-SBS of resin composite stubs to ZrO2 was measured followed by fractographic analysis. The surface roughness and water contact angle were observed to be statistically higher among the femtosecond laser groups compared to the TBC and control groups. The G4 group exhibited the highest EM-SBS among all the groups, irrespective of the ageing conditions used. At the end of 5000 thermocycles, G4 exhibited EM-SBS of 14.05 ± 4.21 MPa compared to 13.80 ± 3.01 MPa in G1 and 5.47 ± 0.97 MPa in G0. The two-way ANOVA revealed a significant effect of both study groups and ageing conditions on the EM-SBS (p < 0.001). Utilization of femtosecond laser technology holds promise as a potential and alternative mechanical retention approach for enhancing the bonding strength of the resin composite to ZrO2.

Adhesion of Orthodontic Braces to Different Restorative Materials: Influence of Surface Conditioning Methods

Adhesion of Orthodontic Braces to Different Restorative Materials: Influence of Surface Conditioning Methods

The Influence of Hydrofluoric Acid Temperature and Application Technique on Ceramic Surface Texture and Shear Bond Strength of an Adhesive Cement.

All-ceramic restorations are the foundation of modern esthetic dentistry. Clinical approaches for preparation, durability, aesthetics, and repair have been reformed by the idea of adhesive dentistry. The aim of the study and the objective question was to evaluate the impact of heated hydrofluoric acid pretreatment and the application technique's influence on the surface morphology and roughness of leucite-reinforced glass-ceramic materials (IPS Empress CAD, Ivoclar Vivadent), which is fundamental for understanding the adhesive cementation process. Scanning electron microscopy was used to observe the effectiveness of the two HF (Yellow Porcelain Etch, Cerkamed) application techniques and the HF's temperature impact on the surface topography of the ceramic. Based on surface conditioning methods, the adhesive cement (Panavia V5, Kuraray Noritake Dental Inc., Tokyo, Japan) was applied to the conditioned ceramic samples and light-cured. Shear bond strength values were correlated with the micro-retentive surface texture of the ceramic. With universal testing equipment at a 0.5 mm/min crosshead speed, SBS values between the resin cement and the ceramic material were assessed until failure. Analyzing the fractured surfaces of the specimens by digital microscopy, the failure modes were divided into three categories: adhesive, cohesive, and mixed failure. Analysis of variance (ANOVA) was used to statistically analyze the collected data. The results show that alternative treatment methods affected the material's surface characteristics and have an influence on the shear bond strength.

ОБЗОР СОВРЕМЕННЫХ МЕТОДОВ ПРЕДВАРИТЕЛЬНОЙ ОБРАБОТКИ ПОВЕРХНОСТИ ДИОКСИДА ЦИРКОНИЯ ДЛЯ УВЕЛИЧЕНИЯ АДГЕЗИИ

With the advent and introduction of composite materials into dental practice at the end of the 20th century, patients' requirements for the aesthetics of prostheses have increased dramatically. At about the same time, a new material appeared – zirconium dioxide, which has good aesthetic qualities, excellent strength characteristics, chemical stability and bio-inertia. However, for all its advantages, it also has a number of disadvantages, one of which is poor adhesion to fixing cements. To date, many methods have been proposed to improve the adhesion of prostheses made of zirconium dioxide, each of which has its own strengths and weaknesses. The purpose of this review is to analyze, compare and systematize existing methods and materials proposed to improve the adhesion of zirconium dioxide to fixing cements, as well as their evaluation to study current trends in surface conditioning methods with predictable results. Materials and methods. This study was conducted using the PubMed search engine. 42 articles were selected for the time period from 2016 to 2022. Search keywords: zirconia, zirconia adhesion, bond strength test. The articles used were selected according to the following criteria: publications in English, in vitro studies, studies with shear/tensile strength tests, systematic reviews. Only articles related to dentistry were considered. Conclusions. The selected literature describes many methods that enhance the adhesion of zirconium to fixing cements. However, their comparison and evaluation are difficult due to the authors' use of various tests and thermal cycling time. This is confirmed by our comparative evaluation of these methods according to criteria independent of each other. Currently, there is no generally accepted and standardized protocol for adhesive preparation of the surface of structures made of zirconium dioxide, which gives time-stable results. Additional research is needed.

Çeşitli Kompozit Rezinlere Uygulanan Farklı Yüzey Pürüzlendirme Yöntemlerinin Porselen Bağlanma Dayanımına Etkisi: İn Vitro Çalışma

Objective: This study compares different surface conditioning methods applied to various composite surfaces in order to investigate the possible effects on composite-ceramic bond strength. It was aimed to increase the bond strength between flowable composite which is frequently used in the immediate dentin sealing procedure and ceramic surfaces. Material and Methods: Eighty flowable composite and eighty conventional composite discs were prepared with five different surface conditioning methods applied to the discs. The folllowing treatments were applied to the discs: orthophosphoric acid, air-flow, bur conditioning, Er:YAG laser irradition and an unconditioned control group. The composite disc surface roughness was measured with a profilometer. Composite and ceramic (Glass-ceramic blocks, e.max CAD, Ivoclar Vivadent AG, Liechtenstein) discs were then bonded with an adhesive resin cement. The shear bonding test was performed with an universal tester. Results: There was no statistical difference between the conditioning methods applied to flowable composites in terms of bond strength (p>0.05). However, a statistically significant difference was found between the conditioning methods applied to conventional composites regarding bond strength (p<0.05). The highest mean bond strength value was observed with ER:YAG laser conditioned conventional composites and was significantly higher than laser irradiated flowable composite groups. Conclusion: Our data shows that similar bond strength values are obtained when using either flowable or conventional composite resins. In addition, both conventional and flowable composite resins require surface conditioning to achieve reliable adhesion to porcelain material.

Effects of different surface conditioning protocols on shear strength of orthodontic brackets bonded to CAD/CAM materials

The aim of this study was to evaluate the effects of different surface conditioning method combinations on the shear strength of orthodontic brackets bonded various temporary crown materials used in computer aided design and computer aided manufacturing systems. 100 polymethyl methacrylate, 100 bis-acrylic composite and 100 polyetherketoneketone surfaces were prepared from provisional temporary crown blocks. Five different conditioning protocols (etching with 9.6 % hydrofluoric acid, sandblasting with 50 μm Al2O3 particles, roughening with ultrafine diamond bur, Er,Cr:YSGG laser irradiating and priming with methylmethacrylate monomer were applied to the surfaces for each material group. Shear test was performed to half of the bonded samples after 24 hours while the other half 14 days later. The share strengths of the bonded brackets were measured in Newton and Megapascals. In all material groups, the highest share strength values were found in samples sandblasted with Al2O3 particles. For bis-acrylic composite and polymethyl methacrylate groups, the lowest bond strength value were found in samples irradiated with Er,Cr:YSGG laser. The shear bond strengths of the orthodontic brackets bonded to the temporary crown materials produced in CAD/CAM systems vary according to the structure of the material and surface conditioning processes.

Comparison of shear bond strength of rebonded stainless steel brackets with three different enamel surface conditioning methods.

During the orthodontic bonding process, the need for repositioning or rebonding of orthodontic brackets on the enamel surface occurs frequently. The aim of this study is to compare the shear bond strength (SBS) in rebonding orthodontic stainless steel brackets with three different methods of enamel surface conditioning methods. In this in vitro study, 80 human premolars that were extracted for orthodontic purposes were randomly divided into four groups and underwent orthodontic bonding procedure (N = 20). Except for the control group, three other groups underwent debonding and rebonding process in which after removing the remaining adhesive with tungsten-carbide bur, enamel surface conditioned by three different methods including re-etching with phosphoric acid, sandblasting + acid etching, and Erbium-doped Yttrium-Aluminum-Garnet laser. Then, the SBS of the bracket to the enamel surface was compared between different groups. Scanning Electron microscopy images were also obtained from a number of samples. Statistical analysis was performed by Kruskal-Wallis and Mann-Whitney tests. The highest SBS was observed in the primary bond (control group) with an average of 29,440 MPa. There was a significant difference between the studied groups (P < 0.001) and only the group that was re-etched with phosphoric acid had no significant difference with the control group (P = 0.708) ∝ =0.05. Rebonding of brackets using phosphoric acid for reconditioning of the enamel surface creates bond strength comparable to the primary bond. Other groups had significantly lower SBS than the control group.

Bonding of orthodontic ceramic brackets: Optimal conditioning method of lithium disilicate restorations

Introduction. According to the data obtained from the American Orthodontic Society survey conducted in 2015, the number of adult patients that requested orthodontic treatment increased from 14% to 27% between 2010 and 2014. Because of the increased age of the patients, fixed orthodontic treatment is expected to be performed on restored teeth, including all ceramic restorations. The objectives of the present study were to evaluate the influence of different surface treatments on the bond strength of ceramic brackets to lithium disilicate ceramic and to determine the mode of fracture. Material and method. 45 ceramic rectangular specimens were obtained from lithium disilicate CAD/CAM blocks which were divided in five groups according to the performed surface conditioning method: 1. grinding with a fine diamond bur (control group); 2. sandblasting with 29 ?m alumina (Al2O3); 3. etching with 4% hydrofluoric acid (HF); 4. sandblasting followed by conditioning with a universal primer - silanization (Al2O3 + S); 5. HF acid etching followed by silanization (HF + S). Shear bond strength test was performed after storing the samples in water bath for 7 days. All of the fractured samples were analyzed with optical microscope to determine the type of fracture. Results. HF acid etching followed by silanization performed the highest bond strength of 8.03 MPa, while sandblasting followed by silanization - 6.69 MPa. Mechanical surface conditioning with either HF acid etching or sandblasting resulted in significantly lower bond strength (2.65 MPa and 1.51 MPa respectively). Mainly adhesive mode of fractures was noticed after sandblasting and silanization, indicating minor chance of damaging the ceramic restoration after debonding, at the end of the orthodontic treatment, unlike the ceramic specimens in the Group 5 (HF + S) with 42.8% mixed and 14.4% cohesive fractures; 100% adhesive fractures were observed after mechanical treatments. Conclusion. According to the SBS test results and fracture type, sandblasting followed by the application of a universal primer can be considered as an adequate method for conditioning the lithium disilicate ceramic restorations before the bonding of ceramic orthodontic brackets.

The Effecacy of Different Surface Conditioning on Shear Bond Strength of Orthodontic Bracket Bonded to Lithium Disilcate Crowns; An in Vitro Study

Background and objective: Lithium disilicate widely used, and it is important to correctly bond orthodontic brackets to such materials. This study aimed to assess the impact of various types of surface conditioning methods on the shear bond strength (SBS) of orthodontic metal brackets to lithium disilicate crown. Materials and methods: In this in vitro study, 30 lithium disilicate specimens were prepared based on the type of surface conditioning into three surface conditioning groups (n=10 for each group). First group the semi-crowns surface was conditioned with 10% hydrofluoric acid etching, the second group was micro-etched with sandblast particles (50 um aluminum oxide particles) and the last group was conditioned with ultrasonic scaler. Valo light cure was utilized with 3200mw/cm2 light intensity. SBS was measured using a universal testing machine. The findings were statistically examined. Result: The results showed significant difference among the three groups where the sandblasting group had the higher mean of SBS, while the hydrofluoric acid etching group had the lower value and in between, the mean of ultra-sonic intermediate. &nbsp;&nbsp;&nbsp; &nbsp;Conclusions: &nbsp;Although the means of the three types of surface conditioning were significantly different, shear bond strength was positively affected by all of them and subsequently all types may be considered recommended techniques for reliable shear bond strength

Effect of Adhesive Resin Application on the Durability of Adhesion to CAD/CAM Glass-Ceramics after either Hydrofluoric Acid Etching or Self-etch Primer Application.

To evaluate the effect of two surface conditioning methods, namely conventional hydrofluoric acid vs self-etching primer, and the application of adhesive on the bond strength of resin cement to CAD/CAM glass-ceramics. Blocks (N = 96) (12 x 10 x 2.5 mm) were manufactured, 24 for each tested ceramic type: lithium silicate ceramic (LS), polymer-infiltrated ceramic (PIC), leucite-reinforced feldspathic ceramic (FD), and lithium-disilicate glass-ceramic (LD). For bond strength testing, 64 blocks were randomly divided into 16 groups (4 blocks per group) according to the following factors: ceramic: 4 levels; etching: 2 levels (HFS: hydrofluoric acid + silane or Monobond Etch & Prime [MEP]); and adhesive application: 2 levels, with (signified as A) and without. Then for each group, 15 resin cement cylinders (AllCem Dual, FGM) were built up. All specimens were subjected to thermocycling (10,000 cycles) and to shear bonding strength testing (SBS) (100 kgf, 0.5 mm/min). Mean shear stresses (MPa) were statistically analyzed by three-way ANOVA, Tukey's test, and Weibull analysis. The mean bond strength of group PIC-HFS-A (28.45 ± 7.6 MPa) was significantly higher than that of groups LS-HFS-A (12.11 ± 2.7MPa) and FDHFSA (20.86 ± 2.0MPa). Group PIC-HFS bond strength (25.02 ± 6.5 MPa) was significantly higher only when compared to group LS-HFS (15.82 ± 4.4 MPa). The LS group presented lower SBS compared to all other groups. No significant differences were found between HFS and MEP surface treatments. Surface treatment with MEP promotes adhesion similar to that of HFS. Additional application of adhesive after the surface treatments did not improve the bond strength.

Effect of femtosecond laser and sllica-coating on zirconia framework-veneering ceramic bonding, surface chemistry and crystallographic changes

The aim of this study was the assessment of various surface conditioning methods upon zirconia framework veneering ceramic bonding, crystallographic changes, and surface chemistry. 91 prepared zirconia specimens were randomly assigned to 4 groups (n = 18) according to conditioning method: Group SB: Air-borne-particle abrasion with 50 µm Al2O3; Group R: Tribochemical silica coating; Group FL: Femtosecond-laser application; Group Si25: argon/oxygen plasma (8:1 in flux) film deposition on the zirconia surface for 25 min and Group Si49: as in Si25 but only 49 min. The veneering ceramic was fired upon the zirconia surface and the interface of the framework-veneer assemblies were subjected to shear force using a Universal Testing Machine (1 mm/min). Three specimens from every group were analyzed with profilometry and SEM. Data were statistically analyzed using a One-way ANOVA and Tukey’s test for multiple comparisons (α = 0.05). Failure modes were obtained and SEM-EDX was used to identify tetragonal to monoclinic transformation phase change. Group Si49 (32 ± 3) presented the highest mean bond strength values (MPa) followed by Group Si25 (28 ± 6) being not significant from one another (p > 0.05). Groups SB (15 ± 5) and R (16 ± 5) did not show significant difference (p > 0.05), being significantly less than that of Group FL (22 ± 6) (p < 0.05). All groups presented predominantly mixed failures. Silica-based coating was most effective in terms of bond strength, minimal flaws and transformation in the zirconia tested.

Effect of Different Surface Modifications of Acrylic Teeth and Thermocycling on Shear Bond Strength to Polycarbonate Denture Base Material.

During prosthodontic clinical practice, the most commonly reported type of failure is the debonding of teeth to the denture base. Incompatible surface conditions at the tooth/denture base interface result in a lack of bonding. This study aimed to study the influence of different surface modifications of acrylic teeth and thermocycling on shear bond strength to polycarbonate denture base material. Eighty cylinder-shaped samples were fabricated. The tested samples were divided into 4 groups (n = 20). Group A represents the control group, group B represents the mechanical modification of the tooth, while group C and group D represent the chemical treatment of the tooth with ethyl acetate and bonding agent, respectively. Each group was further subdivided into 2 categories depending on the thermocycling procedure (N = 10). All samples were tested for shear bond strength tests. A computer-controlled universal testing machine performed the shear bond test at a 0.5 mm/min crosshead speed. Three-way ANOVA (P=0.05) was used for the statistical analysis of the data. Results show that shear bond strength was significantly affected by the surface treatment, whether it is mechanical or chemical (P ≤ 0.01) (B > D > C) compared with a control group (A). However, thermocycling has a nonsignificant decrease in the bond strength values in all experimental groups (P > 0.05) (B > D > C > A). The mechanical treatment by creating retentive holes (B) provides better results than the chemical surface treatment with a bonding agent and ethyl acetate (D and C, respectively). This study concluded that various surface conditioning methods affect the bonding strength of acrylic teeth and polycarbonate denture base material with no effect of thermocycling.

Comparison Of The Effect Of Surface Conditioning Methods On The Bond Strength Of Different Zirconia Reinforced Lithium Silicate And Hybrid Ceramics To Resin Cement

OBJECTIVE. The objective of this study was to evaluate the effect of surface conditioning methods on shear bond strength (SBS) of a resin composite bonded to CAD/CAM materials.&#x0D; &#x0D; METHODS. The zirconia-reinforced lithium silicate (Vita Suprinity VS, and Celtra Duo CD) and hybrid ceramics (Vita Enamic, VE and Nacera Hybrid NH) were used. 80 specimens from each material were fabricated following the manufacturer’s instructions and divided into 8 groups according to surface treatments. These were; Gr 1 (control, no treatments (K)), Gr 2 (hydrofluoric acid H), Gr 3 (H+ Silane S), Gr 4 (abraded with 50-micron alumina particles A), Gr 5 (A+ S), Gr 6 (abraded with 30-micron Cojet sand C), Gr 7 (C+S), Gr 8 (S). The average surface roughness (SR) of the specimens was measured. Surface treated specimens were cemented to the resin cement (Panavia F 2.0) for testing the adhesion using the shear bond strength SBS test and were tested. Mean SR and SBS results were analyzed by 2-way ANOVA with the material type and surface treatments as the independent variables. &#x0D; &#x0D; RESULTS. The highest surface roughness values were observed in the A and AS groups. Both hybrid ceramics VE and NH showed the highest SR values among surface treatments. The highest SBS values were found usually on the H and HS treated surfaces. The highest values were observed on the CD material in the HS group (18,01MPa) and followed by the VE material (16,25 MPa) in the CS group. The failure mode for CD and VS materials was found adhesive and cohesive failures and for VE and NH materials adhesive, and mixed cohesive failure was observed.&#x0D; &#x0D; CONCLUSION. The surface treatment showed a significant effect on the SR and SBS values. Although, the SR values of the materials are high in the A and AS group, the highest SBS values were observed in the H and HS treated surfaces.

Development of Technology for Vacuum Surface Conditioning by RF Plasma Discharge Combined With DC Discharge

Introduction. It is important to decrease light and heavy impurities influxes towards the plasma volume during the high temperature plasma experiments in fusion devices. This is why the conditioning of the wall inner vacuumsurfaces is a basic part of the fusion device operation.Problem Statement. The conventional inner vacuum chamber surface conditioning methods has a significant drawback: sputtering materials in a vacuum chamber. The inner vacuum surfaces can be also conditioned with radio-frequency (RF) discharge plasma, but the conditioning effectiveness is limited by low ion energy.Purpose. The purpose of this research is to develop vacuum surface conditioning technology by the radio frequency plasma combined with DC discharge. Materials and Methods. The noncontact passive method of optical plasma spectroscopy has been used to estimate ion plasma composition. The stainless steel outgassing has been determined in situ with the thermodesorption probe method. The sputtering of the samples has been measured with the weight loss method.Results. The studies of combined discharge have shown that: the anode voltage of combined discharge is lower than in case of the glow discharge; the stainless steel 12Kh18N10T erosion coefficient is about 1.5 times less in thecase of combined discharge than in the glow one; the thermal desorption diagnostic of wall conditions in the DSM-1 has shown better efficiency with the combined discharge as compared with the glow discharge. Theproposed technology is an original one and has no analogs.Conclusions. The reported research results have shown good prospects for the combined discharge usage for plasma walls conditioning and opportunities for using the combined discharge technology for big fusion machines.

Adhesion to Zirconia: A Systematic Review of Surface Pretreatments and Resin Cements.

This systematic review aims to evaluate the different pretreatments of the zirconia surface and resin cement in order to determine a valid operative protocol for adhesive cementation. Methodologies conducted for this study followed the Prisma (Preferred Reporting Items for Systematic Reviews and Meta-Analysis) guidelines. An electronic search was performed in four databases. The established focus question was: “What type of surface conditioning method is the one that obtains the best adhesion values to zirconia over time by applying a resin cement?” Forty-five relevant papers were found to qualify for final inclusion. In total, 260 different surface pretreatment methods, mainly combinations of air-abrasion protocols and adhesive promoters, were investigated. Altogether, the use of two artificial aging methods, three types of cement and four testing methods was reported. The results showed that mechanicochemical surface pretreatments offered the best adhesive results. Self-adhesive cement and those containing 10-MDP obtained the best results in adhesion to zirconia. Artificial aging reduced adhesion, so storage in water for 30 days or thermocycling for 5000 cycles is recommended. A standardized adhesive protocol has not been established due to a lack of evidence

Evaluation of Efficacy of Various Surface Conditioning Methods on the Repair Bond Strength of Composite to Different Fracture Types of Zirconia Ceramics.

The aim of this study was to investigate the effects of different surface treatment methods on shear bond strength between composite resin and different levels of zirconia ceramic. Laser surface-conditioning procedures have been reported as effective method to increase repair bond strength of composite to zirconia ceramics. Detailed information of effects of Er,Cr:YSGG laser treatment with different pulse rates on the zirconia ceramics is lacking in the literature. 120 disc-shaped specimens were prepared including zirconia, veneering ceramic, and 50% veneering ceramic-50% zirconia surfaces. Four different surface treatments were applied to the specimens. These were grinding with diamond bur, sandblasting, and short and long pulse rates of Er,Cr:YSGG laser irradiation. An intraoral ceramic repair kit was used to repair specimens, and shear bond strength was performed on the composite resin to each specimen. The highest mean bond strength was seen in the veneering ceramic surface that was ground using a diamond bur, and the lowest mean bond strength value was observed in the same surface that was treated with long pulse laser irradiation. The sandblasting with alumina particles exhibited lower mean repairing bond strength among the rest of used methods in this study for the group which contained half of the veneering ceramic and half of the zirconia. Sandblasting and Er,Cr:YSGG laser using surface treatment procedures obtained appropriate bond strength for the group that included 50% veneering ceramic-50% zirconia, because of no significant differences observed among the applied surface conditioning methods in this group.