Search

Among a broad spectrum of AM technologies, electron beam melting (EBM) is widely applied in AM process for producing titanium alloy parts. In general, AMed metal products have very rough surface of more than 200µm R z, since relatively large beads are arranged on their surface by scanning electron beam. Moreover, surface irregularities such as spatter and cavity are also generated on the surface. Rough surface and surface irregularities would lead to reduction in surface strength and poor appearance. Therefore, post surface finishing processes are required to smooth the surface of AMed metal products. One of the common surface smoothing processes is abrasive blasting. Large surface roughness can be decreased by abrasive blasting, and compressive residual stress can be introduced to the surface. However, there is a limitation to reduction of surface roughness. On the other hand, in large-area electron beam (large-area EB, LEB) irradiation method developed recently, mold steel surface can be finished by melting it in a few minutes. However, it is not easy to smooth surface with large initial surface roughness, and a tensile residual stress may be generated on the surface. In this paper, surface smoothing of AMed titanium alloy by combination of abrasive blasting and large-area EB irradiation was proposed. At first, the AMed titanium alloy surface was blasted to reduce the initial large surface roughness to some extent and change the surface topography. Then, large-area EB was irradiated to the blasted surface. It is made clear that surface roughness significantly decreases when large-area EB is irradiated to the blasted surface with small mean width. Moreover, tensile residual stress generated in large-area EB irradiation can be reduced by abrasive blasting. Therefore, combination of abrasive blasting and large-area EB irradiation is effective for efficient reduction of large surface roughness of AMed titanium alloy. [ABSTRACT FROM AUTHOR]

Zirconium oxide is a ceramic most often used in the field of dentistry for permanently cementing the substructures of prosthetic restorations in patients. The surface of zirconium oxide should be prepared properly because in the next stage it must be covered with porcelain. The success of prosthetics treatment depends on various factors, but it has been reported that the transformation of zirconium oxide plays a key role. The purpose of the research was to investigate the effect of abrasive blasting on the transformation of zirconium oxide. The research has shown that this type of surface treatment causes the transformation of the tetragonal phase into a monoclinic one. The samples were examined using X-ray diffraction (XRD). The study confirmed the assumption. [ABSTRACT FROM AUTHOR]

This study presents a numerical investigation of rocket plumes carrying regolith particles in the context of the lunar environment (gravity and vacuum conditions). We investigated two lander masses with a single rocket hovering at 5 different low altitudes perpendicular to a flat surface. For the regolith, we considered 9 particle sizes, with diameters from 1 μ m to 1 cm. The initial condition of all particles was a null velocity at 0. 3 m above the ground. The particles started at 19 different radial positions from the centerline of the rocket jet, 1 m to 10 m. We used a DSMC method to solve the rocket plume cases, considering the combustion product molecules from the propellant N 2 O 4 +Aerozine 50. Steady-state plume flow solutions are one-way coupled with discrete particles, considering drag and weight forces. The results showed that particle angle is nearly constant for small ( d p < 100 μ m) particles varying with initial radial position and lander altitude. Particle velocity is related to particle diameter as a power-law function and a Gaussian function of the initial particle position. Lander altitude and mass modulate the magnitude of particle velocity. Using the numerical solution data, we derived a numerical correlation for particle velocity that provides insight to avoid regolith abrasive blasting into the lunar lander, surrounding structures, and orbital satellites. • Lunar rocket plumes are highly influenced by the altitude and mass of the lander. • Particles accelerated by rocket plumes may damage surrounding structures. • Trajectory angle of small particles are less sensitive to their size. • Particle damage potential can be estimated through numerical correlation. [ABSTRACT FROM AUTHOR]

In this study, four protective coating materials: Inconel 718, Inconel 625, Alloy 33 and Stellite 6 were deposited on 16Mo3 steel tubes by means of CMT (Cold Metal Transfer), as an advanced version of MAG (Metal Active Gas) welding method. In the next step, the surface of the deposited coating was remelted by means of TIG (Tungsten Inert Gas) welding method. SEM microstructure of coatings–substrate has been reported, and an EDX-researched chemical composition of the coatings was compared to the nominal chemical composition. The hardness distribution in the cross-section was performed, which revealed that among investigated coatings, Stellite 6 layer is the hardest, at about 500 HV0.2. Other materials such as Inconel 625, Inconel 718 and Alloy 33 represented a cladded zone hardness about 250 HV0.2. Stellite 6 layer had the lowest wear resistance in the dry sand/rubber wheel test, and Stellite 6 layer had the highest wear resistance in the erosive blasting test. This proved the existence of different wear mechanisms in the two test methods used. In the dry sand/rubber wheel test, the Alloy 33 and Inconel 718 only represented higher wear resistance than substrate 16Mo3 steel. In abrasive blasting tests all coatings had higher wear resistance than 16Mo3 steel; however, Stellite 6 coatings represented an approximately 5 times higher durability than other investigated (Inconel 625, Inconel 718, and Alloy 33) coatings. [ABSTRACT FROM AUTHOR]

Sandblasting injuries are uncommon with only four reports in literature. We report a patient with a sandblasting injury of the dorsum of the hand and wrist and summarise published literature on the management of such injuries. We recommend early (<24 hours) C-arm-guided debridement of embedded foreign bodies and repeated saline washouts with a soft surgical scrub brush. Level of Evidence: Level V (Therapeutic) [ABSTRACT FROM AUTHOR]

The required connector dimension for zirconia fixed dental prostheses (FDPs) may be a clinical limitation due to limited space in the occlusogingival direction. Using no veneering in the gingival regions of the pontics and connectors may solve this problem. This study evaluated the mechanical durability of zirconia FDPs with and without veneering in the gingival area of the connectors and pontics and subsequent airabrasion of this region with different protocols. Models were made of resin abutments (diameter = 6 or 8 mm, height = 6 mm, 6 degrees convergence) and embedded in polyurethane resin (distance = 11 mm). Zirconia frameworks were milled and randomly distributed by veneering (veneering of the entire framework [VEN] or no veneering at gingival regions of the pontic and connector [NVEN]) and by air-abrasion (Al2O3/SiO2, 30 μm; or 45 μm Al2O3. FDPs were adhesively cemented and subjected to mechanical cycling (1,200,000 cycles, 200 N, 4 Hz, with water cooling). Specimens were tested until fracture (1 mm/min), and failure modes were classified. Data (N) were subjected to one-way analysis of variance in two sets, Tukey test (α = .05) and Weibull analysis. While veneering did not significantly affect the results (VEN: 1,958 ± 299 N; NVEN: 1,788 ± 152 N; P = .094), air abrasion did (P = .006), with the worst results for the groups conditioned with 45 μm Al2O3 (SiO2: 1,748 ± 273 N; Al2O3: 1,512 ± 174 N). The NVEN group demonstrated the highest Weibull modulus (12.8) compared with the other groups (5.3–7.2). Fractures commonly initiated from the gingival side of the connector. Veneering of the gingival region of the connectors and pontics in zirconia FDPs did not diminish the fracture strength, but air-abrasion of this area with 45 μm Al2O3 decreased the results. [ABSTRACT FROM AUTHOR]

This paper focuses on the manufacturing and quality evaluation of fibre-reinforced polymer matrix composite coatings deposited by hand lamination on DC04 steel substrates. Two matrices (polyurethane and epoxy resins) and four different reinforcement materials were considered (glass, carbon, aramid, and carbon-aramid hybrid fabrics). Various methods of surface preparation and roughness development were used in order to enhance the adhesion: cleaning with acetone, abrasive blasting with F80 alumina or GH40 cast steel shot. Manufactured samples were subjected to roughness and coating thickness measurements, wettability analysis, and pull-off strength tests. Afterwards, the microscopic analysis of cross-sections of the samples and the identification of type of the failure were performed. The increase in surface roughness was beneficial, to some point, for the coating's adhesion. The highest pull-off strength values were obtained for polyurethane coating reinforced with glass fabric after abrasive blasting with the use of F80 alumina (5.78 MPa) and epoxy resin with aramid reinforcement (5.20 MPa) after pretreatment with GH40 cast steel shot. [ABSTRACT FROM AUTHOR]

Background and Objective: Various techniques have been introduced to improve bond strength of zirconia which may negatively affect flexural strength. This study aims to evaluate the effects of different sandblasting parameters on micro-shear bond strength (MSBS, Mpa) and biaxial flexural strength (BFS, Mpa) of Zirconia. Methods: In this in vitro study, zirconia blocks were cut into 180 discs for MSBS and BFS tests (90 specimens in each group). For each test, they were divided into one control group and 8 experimental groups according to the type of sandblasting regimen (pressures of 4 or 6 bar, duration of 14 or 21 seconds, and alumina powder sizes of 50 or 110 µm, n=10). A universal testing machine was used to determine MSBS and BFS. X-ray diffraction (XRD) analysis was then performed. Findings: According to the results, groups with 110 µm particles (4 bar-14 s, 6 bar-14 s, 4 bar-21 s and 6 bar-21 s with MSBS values of 34.43±5.99, 35.21±6.39, 27.17±3.95 and 28.66±3.92 Mpa, respectively) had significantly higher MSBS values compared to the control group (p<0.001, p<0.001, p=0.034, p=0.005, respectively). Groups with 110 µm-21 s sandblasting regimen (with pressure of 4 and 6 bar with BFS values of 1031.69±90.00, 1062.56±91.29, 962.30±93.24, respectively) and those with 50 µm-6 bar-21 s sandblasting regimen had statistically significant lower BFS values compared to the control group (p<0.001). According to XRD analysis, groups with 110 µm powder size and 21 s sandblasting resulted in more monoclinic phase. Conclusion: This study demonstrated that sandblasting with larger powder size and shorter duration could increase MSBS without any negative effects on BFS. [ABSTRACT FROM AUTHOR]

The influence of surface roughness on adhesive joint strength for polymer coating reinforced with various fabrics to aluminum substrate was investigated. PA11 aluminum alloy was chosen as the substrate, which was prepared in two different methods: degreasing with acetone or abrasive blasting. Two different abrasives (F80 fused alumina or GH40 cast steel grit) were used for mechanical treatment to obtain different roughness parameters. The coatings were made of two matrices (polyurethane and epoxy resins) and four different reinforcement materials (glass, carbon, aramid, and carbon-aramid hybrid fabrics). The manufactured samples were subjected to roughness and coatings' thickness measurements, wettability evaluation, and pull-off strength tests. Various mechanisms of detachment were observed. The increase in substrate roughness had a positive effect on the pull-off strength. The highest pull-off strength values were obtained for unreinforced polyurethane coating (4.46 MPa) and epoxy resin with glass fabric (3.07 MPa) after pretreatment with abrasive blasting with the use of F80 fused alumina. [ABSTRACT FROM AUTHOR]

Avoiding harmful passivation of the lithium metal surface during its implementation as an anode material is a challenge to its use in rechargeable lithium metal batteries. It is critical to control the chemical composition and the morphology of the native passivation layer and to avoid contamination by lubricants or other substances involved in the processing. Herein, abrasive blasting is used as a physical method to achieve clean and 3D‐structured lithium metal electrodes. The careful choice of the abrasive agent and the blasting parameters results in well‐controlled surface properties. The blasted lithium electrodes exhibit significantly lower overvoltages with values as low as 10 mV at 0.1 mA cm−2. Electrochemical impedance spectroscopy shows that blasted lithium has interface resistances that are up to five times smaller than those of untreated lithium. The effectiveness of blasting as a cleaning method is clear even in the case of thicker and highly resistive passivation layers occurring after exposure to ambient air. [ABSTRACT FROM AUTHOR]

This study investigates the effectiveness of using a 3 kW rotary continuous-wave laser transmitter for removing salt from severely corroded steel surfaces. It proposes an improved surface treatment flow that includes laser treatment as a pre-treatment step. This study focuses on severely corroded weathering steel with artificial corrosion pits that require painting after surface treatment to prevent corrosion under the film. This study demonstrates that the laser can effectively remove salt during the rust removal process, and the proposed surface treatment flow can prevent the re-corrosion of more than 5 % of the treated surface area in high-temperature, high-humidity environments for one week, providing a quality surface for paint coating. This study suggests that laser surface treatment can be used as a pretreatment step for abrasive blasting and should be further explored and promoted in engineering applications. • Demonstrated laser surface cleaning outperforms abrasive blasting in removing salts. • Introduced an improved Turning Time Test method for quantitative assessment of salt residues on surfaces before paint coating. • Proposed a combined laser and blasting protocol that significantly reduces the risk of under-film corrosion. • Demonstrated the suitability of laser cleaning as a preliminary step for abrasive blasting and recoating processes. [ABSTRACT FROM AUTHOR]

• Ti-15Zr alloy is subjected to abrasive blast acid etching hydrothermal treatment. • The elastic modulus of SLA and SLA-Sr were close to human bone tissue. • The higher the concentration of Sr, the faster the Sr ions are released. • With the increase of Sr content, the cell proliferation effect was more obvious. The Ti-15Zr alloy was used as the substrate in this study, which was modified by sandblast acid-etching (SLA), and the Sr ions were loaded onto the surface of the SLA by using the hydrothermal method (SLA-Sr). The results showed that the Sr ions were attached to the surface of the material in the form of granular SrTiO 3. The modulus of elasticity of SLA and SLA-Sr is closer to that of human bone tissue. The higher the concentration of Sr, the greater the corrosion resistance. The SLA and SLA-Sr had superior hydrophilic and hemolytic properties than Ti-15Zr, and the higher the Sr concentration the better the cell proliferation effect. [ABSTRACT FROM AUTHOR]

Objectives: Evaluation of surgical and non-surgical air-polishing in vitro efficacy for implant surface decontamination. Material and methods: One hundred eighty implants were distributed to three differently angulated bone defect models (30°, 60°, 90°). Biofilm was imitated using indelible red color. Sixty implants were used for each defect, 20 of which were air-polished with three different types of glycine air powder abrasion (GAPA1–3) combinations. Within 20 equally air-polished implants, a surgical and non-surgical (with/without mucosa mask) procedure were simulated. All implants were photographed to determine the uncleaned surface. Changes in surface morphology were assessed using scanning electron micrographs (SEM). Results: Cleaning efficacy did not show any significant differences between GAPA1–3 for surgical and non-surgical application. Within a cleaning method significant (p < 0.001) differences for GAPA2 between 30° (11.77 ± 2.73%) and 90° (7.25 ± 1.42%) in the non-surgical and 30° (8.26 ± 1.02%) and 60° (5.02 ± 0.84%) in the surgical simulation occurred. The surgical use of air-polishing (6.68 ± 1.66%) was significantly superior (p < 0.001) to the non-surgical (10.13 ± 2.75%). SEM micrographs showed no surface damages after use of GAPA. Conclusions: Air-polishing is an efficient, surface protective method for surgical and non-surgical implant surface decontamination in this in vitro model. No method resulted in a complete cleaning of the implant surface. Clinical relevance: Air-polishing appears to be promising for implant surface decontamination regardless of the device. [ABSTRACT FROM AUTHOR]

The aim of this study was to identify the relative strengths and weaknesses of different interfaces within the multilayer structure of a zirconia crown restoration when applying different surface pretreatments. These include the influence on shear strengths of different air abrasion protocols, glaze-on techniques, zirconia primers and self-adhesive cements for either the complex structure: zirconia / self adhesive resin composite cement (RCC) / bovine dentin substrate (part 1) or the RCC / zirconia substrate (part 2). In Part 1, zirconia discs, pretreated by either glaze-on techniques or air abrasion using Rocatec™ Soft, were bonded to bovine dentin substrates with different self-adhesive RCCs. In Part 2, steel-cylinders were bonded to zirconia cuboid substrates, pretreated by either different protocols for air-abrasion or a glaze-on-technique, with different self-adhesive RCCs. Shear bond strengths (SBS) were measured for all interfacial combinations. In part 1, application of air abrasion using Rocatec™ Soft significantly increased the SBS of zirconia to dentin compared to control specimens without pretreatment, while glaze-on techniques did not increase the SBS. Pretreatment of zirconia surfaces with two primers (either Clearfil Ceramic Primer, or Monobond S) showed significantly higher SBS than the controls. Cementations with RelyX Unicem 2 Automix showed significantly higher SBS than with MaxCem Elite. In Part 2, all air abrasion protocols increased the SBS, but there was no significant difference between these protocols. Again the glaze-on technique did not increase SBS. A significant difference between the two RCCs was again observed. When zirconia substrates were air abraded, regardless of which protocol was applied, the highest SBS were obtained by Calibra with P&B active followed by Panavia with or without Clearfil Ceramic Primer Plus. Calibra applied without P&B active exhibited the lowest SBS. Pretreatment of zirconia substrates using air abrasion and/or ceramic primers increased the SBS of the zirconia cement interface. For all tested glaze-on treatments, in our experimental setting no effect was observed. [ABSTRACT FROM AUTHOR]

An innovative low-cost method of aluminium surface treatment to obtain stable superhydrophobic properties is presented. An aluminium anodising method was combined with surface abrasive blasting as a mechanical pre-treatment to obtain combined microscale roughness and nonporous surface structure. The produced layer was impregnated with fatty acid. The surface morphology was examined by SEM and optical microscopy. The influence of the process parameters on the wettability of the aluminium surface was investigated. The features of the prepared samples were tested in terms of the durability of the coating. The test results confirm the stable superhydrophobic properties of the obtained layers with contact angle larger than 150° and roll-off angle less than 5°. [ABSTRACT FROM AUTHOR]

The recent developments in mineral processing led researchers to look for alternative methods and propose new mechanisms for enhancing the efficiency of relatively costly processes (e.g., flotation, aggregation), where especially dealing with fine particles. Finer the particles, the higher the role of their surface on their behavior and properties. The importance of particle morphology becomes even clearer when particle-particle and particle-bubble interactions are considered. In this study, the effect of particle shape "roundness" on the surface wettability and flotation response was investigated upon producing fine particles with the "abrasion blasting" method. In order to provide a fundamental perspective, adsorption measurements were also carried out along with the flotation experiments under the same conditions. In addition to these, zeta potential measurements were also carried out with both spherical and blasted particles as a function of collector concentration. The results suggested that the roundness of particles decreased up to a certain nozzle pressure value, which was followed by higher adsorption degrees and consequently higher flotation recoveries. Additionally, settling rate tests were also performed with very fine material to show the effect of particle morphology on particle-particle interactions. The results showed that while lower settling rate values were obtained for spherical ones, higher values were obtained in the case of the ground and blasted samples in the presence of DI water. It was concluded from this study that the "Abrasive blasting method" could be an effective alternative for tuning the surface morphology of particles and their wettability, which in turn can affect the particleparticle interactions in the system. [ABSTRACT FROM AUTHOR]

Results obtained from measuring the required amount of steel abrasive material with various fragmentations, which is transported by a special kind of scraper conveyor, offers information that is useful for operators of the abrasive blast cabinets. The presented article describes an innovative methodology developed for determination of the most relevant operational parameters relating to the above-mentioned situation. The most important parameters in this case are: the optimal amount of the abrasive material, the conveying speed of the scraper conveyor and the feeding of the conveyor with regard to partial or full elimination of instable operational area. Elimination of the instable operational area is possible by means of a simple constructional modification of the given conveying system according to the results obtained from experimental investigation, which was performed using special, originally developed laboratory testing equipment. [ABSTRACT FROM AUTHOR]

• Cold Atmospheric Plasma (CAP) is an emerging technology with a great potential in implant dentistry. • CAP is suitable for degrading oral biofilms formed in situ on Titanium (Ti) surfaces, without causing alterations to Ti surface topography. • CAP cleaning efficacy is greater on machined than on moderately rough discs. • CAP did not show any additive effect with air abrasion (AA) in the in vitro model used in the present study. The aim of the present study was to assess the decontamination efficacy and titanium surface alterations of erythritol based air abrasion (AA) and cold atmospheric plasma (CAP) targeting a human complex biofilm. Saliva collected from a peri-implantitis patient was used to develop in vitro human biofilm over titanium discs with machined (group A) and moderately rough (group B) surface. The discs were treated with AA, experimental CAP or a combination of both treatments (COM). The amount of biofilm on the discs was measured by crystal violet (CV). Surface features and roughness before and after treatment were assessed by SEM and laser profilometry, respectively. The data were statistically analyzed using Kruskal Wallis followed by Dunn's multiple comparison test after being checked for normality by Shapiro-Wilk test. All the discs in group A performed better to treatments compared to group B. In both groups, CV data showed significantly lower amount of biofilm after AA treatment compared to CAP (p < 0.05). Cleaning efficacy revealed relevant decontamination of both the surfaces following AA and COM treatments and almost complete biofilm removal after AA application on group A (99.92%). SEM analysis demonstrated no post-treatment alterations on the discs and laser profilometry did not show statistically significant changes in S a and S dr values. Decontamination with AA delivering erythritol with or without CAP is highly effective in biofilm removal from different titanium surfaces. All the tested treatments, including CAP showed no noticeable alterations of the titanium discs surface features. Further in vivo studies are necessary to understand the potential of CAP technology in implant surface decontamination. [ABSTRACT FROM AUTHOR]

Laser welding is one of the most promising joining techniques to realize hybrid joints between metals and polymers in order to achieve weight reduction and functionalization of the parts. The surface treatment of the metal has a decisive effect on the joint quality and thus on the mechanical properties. In the present study, different mechanical and laser-based surface treatments have been investigated to develop diverse surface conditions on aluminum. Abrasive blasting and laser ablation were used to increase the surface roughness, while abrasive polishing and laser polishing were applied to minimize the surface roughness. In contrast to abrasive surface treatments, laser-based ones were implemented to create artificial oxide layers on the aluminum surface. The surface structures of pretreated samples have been studied with scanning electron microscopy and roughness test. The laser welding of pretreated aluminum with polyamide was achieved with the heat conduction joining technique. To enlarge the welding area and control the heat input, spatial and temporal modulations of the laser beam were implemented. Finally, a single lap tensile-shear test, microscopic analysis of fractured surfaces, and welding cross sections were employed to evaluate the joints. Results show that the presence of an artificial aluminum oxide layer and low roughness are essential to achieve a superior joint between aluminum and polyamide (improvement of approximately 58% in the shear load of the joint compared to as-received welded samples). The cross section of the superior joint which is the laser-polished aluminum welded to polyamide is studied with transmission electron microscopy. [ABSTRACT FROM AUTHOR]

The present study evaluates an anticorrosive system of epoxy primers applied on carbon steel coupons under different surface preparation techniques: dry abrasive blasting up to Sa 2½, wet abrasive blasting up to Sa 2½ and mechanical treatment up to SSPC SP-11. The epoxy primers were pigmented with zinc phosphate, commonly used in offshore structures, on which intermediary and anti-scaling paints are applied. The components of this primers system were analyzed through Fourier transform infrared spectroscopy (FTIR) while the corrosion protection was analyzed by electrochemical impedance spectroscopy (EIS) and potential monitoring, as well as the adhesion to the coupons' surface immersed in 3.5%w/v NaCl solution (3.5 g of NaCl in 100 mL of solution). The results showed a better epoxy system adhesion to coupons surface prepared by dry abrasive blasting to Sa 2½. According to the electrochemical results, better corrosion protection was observed in samples prepared by wet abrasive blasting up to Sa 2½. [ABSTRACT FROM AUTHOR]

This study investigated the mechanical properties, bond ability, and crystallographic forms of different sites in a highly translucent, multi-layered zirconia disk. Flexural properties, bond ability to resin cement, and phase composition were investigated at three sites of a highly translucent, multi-layered zirconia disk: incisal, middle, and cervical. Flexural strength (FS) and flexural modulus (FM) were measured with static three-point flexural test. Shear bond strength (SB) to resin cement was measured after 24 h storage (37°C). Phase composition under mechanical stress was analyzed using X-ray diffraction. Without air abrasion, FS at the incisal site yielded the lowest value and was significantly lower than the middle and cervical sites. Air abrasion lowered the FS of each site. FM at the incisal site without air abrasion showed the significantly lowest value, and air abrasion increased its FM value. At the middle and cervical sites, their FM values were higher than the incisal site but were not significantly affected by air abrasion. SB value did not show significant differences among the sites. After sintering, cubic zirconia was detected at each site. Rhombohedral phase transformation occurred after mirror polishing. In highly translucent, multi-layered zirconia which was mainly composed of cubic zirconia, rhombohedral phase transformation occurred under mechanical stress and resulted in weakened mechanical properties. [ABSTRACT FROM AUTHOR]

PURPOSE. This study evaluated the shear bond strength between 3D printed provisional resin and conventional provisional resin depending on type of conventional provisional resin and different surface treatments of 3D printed resin. MATERIALS AND METHODS. Ninety-six disc-shaped specimens (Ø14 mm × 20 mm thickness) were printed with resin for 3D printing (Nextdent C&B, Vertex-Dental B. V., Soesterberg, Netherlands). After postprocessing, the specimens were randomly divided into 8 groups (n=12) according to two types of conventional repair resin (methylmethacrylate and bis-acryl composite) and four different surface treatments: no additional treatment, air abrasion, soaking in methylmethacrylate (MMA) monomer, and soaking in MMA monomer after air abrasion. After surface treatment, each repair resin was bonded in cylindrical shape using a silicone mold. Specimens were stored in 37°C distilled water for 24 hours. The shear bond strength was measured using a universal testing machine at a crosshead speed of 0.5 mm/min. Failure modes were analyzed by scanning electron microscope. Statistical analysis was done using one-way ANOVA test and Kruskal-Wallis test (a=.05). RESULTS. The group repaired with bis-acryl composite without additional surface treatment showed the highest mean shear bond strength. It was significantly higher than all four groups repaired with methylmethacrylate (P<.05). Additional surface treatments, neither mechanical nor chemical, increased the shear bond strength within methylmethacrylate groups and bis-acryl composite groups (P>.05). Failure mode analysis showed that cohesive failure was most frequent in both methylmethacrylate and bis-acryl composite groups. CONCLUSION. Our results suggest that when repairing 3D printed provisional restoration with conventional provisional resin, repair with bis-acryl composite without additional surface treatment is recommended. [ABSTRACT FROM AUTHOR]

PURPOSE. To assess shear bond strengths (SBS) of resin composites on aged and non-aged prosthetic materials with various surface treatments. MATERIALS AND METHODS. Cerasmart (CE), Vita Enamic (VE), Vita Mark II (VM), and IPS e.max CAD (EC) blocks were sliced, and rectangular-shaped specimens (14 × 12 × 1.5 mm; N = 352) were obtained. Half of the specimens were aged (5000 thermal cycles) for each material. Non-aged and aged specimens were divided into 4 groups according to the surface treatments (control, air abrasion, etching, and laser irradiation; n = 11) and processed for scanning electron microscopy (SEM). The repair procedure was performed after the surface treatments. SBS values and failure types were determined. Obtained data were statistically analyzed (P=.05). RESULTS. The material type, surface treatment type, and their interactions were found significant with regard to SBS (P<.001). Aging also had a significant effect on prosthetic material-resin composite bonding (P<.001). SBS values of non-aged specimens ranged from 12.16 to 17.91 MPa, while SBS values of aged specimens ranged from 9.46 to 15.61 MPa. Non-aged VM in combination with acid etching presented the highest score while the control group of aged CE showed the lowest. CONCLUSION. Etching was more effective in achieving durable SBS for VM and EC. Laser irradiation could be considered as an alternative surface treatment method to air abrasion for all tested materials. Aging had significant effect on SBS values generated between tested materials and resin composite. [ABSTRACT FROM AUTHOR]

PURPOSE. The bond strengths between resin denture teeth with various compositions and denture base resins including conventional and CAD/CAM purposed materials were evaluated to find influence of each material. MATERIALS AND METHODS. Cylindrical rods (6.0 mm diameter × 8.0 mm length) prepared from pre-polymerized CAD/CAM denture base resin blocks (PMMA Block-pink; Huge Dental Material, Vipi Block-Pink; Vipi Industria) were bonded to the basal surface of resin teeth from three different companies (VITA MFT®; VITA Zahnfabrik, Endura Posterio®; SHOFU Dental, Duracross Physio®; Nissin Dental Products Inc.) using resin cement (Super-Bond C&B; SUN MEDICAL). As a control group, rods from a conventional heat-polymerizing denture base resin (Vertex? Rapid Simplified; Vertex-Dental B.V. Co.) were attached to the resin teeth using the conventional flasking and curing method. Furthermore, the effect of air abrasion was studied with the highly cross-linked resin teeth (VITA MFT®) groups. The shear bond strengths were measured, and then the fractured surfaces were examined to analyze the mode of failure. RESULTS. The shear bond strengths of the conventional heat-polymerizing PMMA denture resin group and the CAD/CAM denture base resin groups were similar. Air abrasion to VITA MFT® did not improve shear bond strengths. Interfacial failure was the dominant cause of failure for all specimens. CONCLUSION. Shear bond strengths of CAD/CAM denture base materials and resin denture teeth using resin cement are comparable to those of conventional methods. [ABSTRACT FROM AUTHOR]

Objective: To evaluate the effects of surface treatment and repair material on the repair shear bond strength (SBS) of the bioactive restorative material. Methods: A total of 240 Activa BioActive Restorative (Activa) discs were prepared, aged, and polished, and divided randomly into eight groups (n = 30). Groups 1–4 discs were repaired with bulk-fill flowable resin-based composite (Bulk-RBC), and Groups 5–8 discs with Activa. Surface treatment used for each repair material type were air abrasion with silica-coated 30-m Al2O3 particles (air abrasion) (Groups 2 & 6), Air abrasion with universal primer (Groups 3 & 7), and Air abrasion with universal adhesive (Groups 4 & 8). Groups 1 and 5 were controls without surface treatment. SBS test was performed, and the failure mode and surface topography were assessed. Results: Surface treatment with air abrasion significantly improved the SBS for repair using both Activa and Bulk-RBC. Repair SBS using Activa was significantly higher compared with Bulk-RBC. Cohesive failure in substrate and mixed failures were most common in the surface-treated groups (2–4, 6–8). Air abrasion produced prominent surface topography changes compared with polishing. Conclusion: Air abrasion enhances the repair SBS of aged bioactive restorative material. The use of the same material (Activa) for repair affords a higher bond strength compared with the use bulk-RBC. [ABSTRACT FROM AUTHOR]

Rough surface profiles are specified for metal surfaces so that corrosion preventative coatings adhere well and provide long-term protection. Simple stylus scans and replica tape are widely used in industry to characterize surfaces and control the quality of surface preparation. Unfortunately, a scientific, quantitative connection between adhesion and surface profile parameters remains unclear. Stereo-pair images from scanning electron microscopy, SEM, were used to digitally reconstruct and then characterize 3D surfaces, which is a technique that seems previously unreported in coatings applications. SEM results were consistent with those from a stylus profilometer, but the data from a surface scan are much more numerous than from a line scan, and SEM can provide very high magnifications. 3D surfaces at high magnification gave larger values for the increase in area developed by the abrasive blasting than were determined at lower magnifications and by the stylus profilometer. Nevertheless, both techniques showed that the surface roughness height and ramification was far less than might be expected from illustrations in the existing literature on coatings' adhesion. Quantified characterization, with details shown at high magnification, may provide scientific insight into how the various features of a roughened surface enhance the adhesion of protective coatings. [ABSTRACT FROM AUTHOR]

Background. Patients seeking orthodontic treatment are increasing, and clinicians often have to place brackets on various surfaces aside from enamel. It is crucial to know what materials or instruments are required to bond brackets to each surface. Objective. This study aims to serve as a clinical guideline for the safest and most effective approaches taken to condition various surfaces for bonding to orthodontic brackets and provide background knowledge on the subject. Materials and Methods. PubMed and EBSCO databases were searched, along with the use of Google Scholar search engine, to obtain relevant articles published in English in peer-reviewed journals, from 1955 to 2020. Keywords used were Shear bond strength; Orthodontic bracket; Base design; Etching; Sandblasting; Laser; Conditioning; Enamel; Ceramic; Porcelain; Gold; Amalgam; Composite. Conclusion. Even though orthophosphoric acid is the most widely used enamel conditioning agent, laser etching should be considered to avoid enamel decalcification. Hydrofluoric acid is the current standard for ceramic conditioning; however, its use intraorally should be minimized due to its toxicity. Orthophosphoric acid, CoJet-Sand air abrasion, and laser etching are viable alternatives for conditioning ceramic. Monobond Etch & Prime is toxic and should not be used intraorally. Composite can be conditioned by bur roughening, and the use of ceramic brackets is recommended. Amalgam and gold surfaces can be conditioned adequately by air abrasion. Despite the claims of many authors, the maximum shear forces that orthodontic brackets are subjected to are not 6–8 mega pascal (MPa). Further investigation is required in that regard. More in vivo studies need to be performed to confirm the in vitro results. [ABSTRACT FROM AUTHOR]

BACKGROUND: Any surface treatments should improve the bond strength of yttria-stabilized tetragonal zirconia polycrystal ceramics without damaging the original strength. Currently, there is no information about the influence of glaze technology on the bond strength of yttria-stabilized tetragonal zirconia polycrystal ceramics, and its influence on the material strength is unclear. OBJECTIVE: To evaluate the effect of glaze technology on the mechanical behavior of yttria-stabilized tetragonal zirconia polycrystal ceramics and on the bond strength with resin cements. METHODS: Yttria-stabilized tetragonal zirconia polycrystal ceramics specimens were prepared and randomly divided into four groups: group A: the surface was not treated; group B: sandblasting with 110 urn AI2O3 particles; group C: glaze + hydrofluoric acid etching; group D: glaze + hydrofluoric acid etching + silanization. The surface morphology, surface roughness, phase transformation, elemental composition, shear bond strength and flexural strength of zirconia specimens after surface treatments were tested. RESULTS AND CONCLUSION: (1) The surface roughness of treatment groups increased obviously, whose descending order was group C (0.62±0.01) µm > group D (0.55±0.02) urn > group B (0.11 ±0.02) urn > group A (0.05±0.01) urn (P < 0.05). (2) The surface of specimens in the group B contained 2.2% monoclinic zirconia, while the content of other groups was zero. (3) In addition to elements of Zr and O, there was 6.49% Al element in the group B specimens, and 18.67% and 25.78% Si element in the groups C and D specimens, respectively. (4) The shear bond strength in the groups A, B, Cand D was (3.11±0.40), (4.23±0.45), (6.62±0.60) and (10.46±0.83) MPa, respectively {P< 0.05). (5) The three-point flexural strength in the groups A, B, C and D was (961.07±75.53), (1 234.73±114.09), (1 024.28±120.51), and (1 036.09±80.10) MPa, respectively, among which the multiple comparison of groups A, C and D showed no significant difference (P > 0.05). (6) The effect of glaze technology on improving the flexural strength of yttria-stabilized tetragonal zirconia polycrystal ceramics is not as obvious as that of sandblasting, but the bond strength between tetragonal zirconia polycrystal ceramics and resin cements can be significantly improved with hydrofluoric acid etching and silanization after glaze. [ABSTRACT FROM AUTHOR]

The blasting technique has been broadly utilized to prepare new surfaces for painting, engraving, etc., in industry. In fact, the minimization of the cleaning cost system is essential. However, the knowledge of this technique in terms of optimization has been poor so far. The aim of this study is to find the optimum replaced boron carbide nozzle diameter for the abrasive blasting system. The basis of the study is to find the replaced nozzle diameter to minimize the cost of the blasting system. Seven main parameters are adopted for examining their influences on the response and the optimum replaced nozzle diameter. The design of experiment (DOE) technique is utilized by using Minitab@19. The results reveal that the initial nozzle diameter has the strongest impact on the optimum replaced nozzle diameter. Furthermore, the proposed regression model has been found to be entirely insistent to the experiments. The utilization of this model can provide an effective way to simplify the calculation of the optimum initial nozzle diameter for boron carbide. [ABSTRACT FROM AUTHOR]

The magmatic evolution of the Early Jurassic Turnagain Alaskan-type intrusion is inextricably linked to terrane accretionary events at the North American continental margin. We have calibrated the multistage assembly of the Turnagain ultramafic–mafic complex using high-precision air and chemical abrasion ID-TIMS U–Pb and 40Ar/39Ar geochronology. Our results are the first published geochronological calibration of zoning in an Alaskan-type intrusion. Three of four intrusive phases (Stages 1–4, oldest to youngest) were successfully dated. Cooling ages obtained on Stage 2 dunite–wehrlite include statistically identical 40Ar/39Ar plateau dates of 187.4 ± 1.5 (2σ) Ma on hornblende and 188.6 ± 1.2 Ma on phlogopite, and a concordant 206Pb/238U date of 190.3 ± 4.6 Ma on titanite. Stage 3 diorite has a 206Pb/238U zircon crystallization age of 188.11 ± 0.13 Ma. Stage 4 wehrlite and leucodiorite yield 206Pb/238U zircon crystallization ages of 185.68 ± 0.19 and 185.30 ± 0.12 Ma, respectively. The ca. 189 Ma phlogopite date represents a minimum crystallization age for Stage 2, indicating that assembly of the Turnagain intrusion spanned at least ∼4 million years from ca. 189 Ma to 185 Ma. Regional progressive contractional deformation in the Early Jurassic is constrained by the geochronological results (>189 to <185 Ma) and initially generated northeast-vergent folds in the country rocks (>189 Ma), deformed Stage 1 wehrlite–clinopyroxenite prior to emplacement of Stages 2–4, and subsequently thrust the intrusion and its host rocks onto the ancient North American continental margin (<185 Ma). Contrary to previous interpretations, new geophysical data support an allochthonous origin for the host rocks of the Turnagain intrusion. The Turnagain host succession is correlated with late Paleozoic arc-related and basinal lithostratigraphic units developed at the inboard margin of the accreted Yukon–Tanana terrane and peripheral to the Slide Mountain marginal ocean basin. The geochronological results rigorously constrain the timing and style of Early Jurassic deformation attending the initial accretion of allochthonous arc terranes in the northern Cordillera. [ABSTRACT FROM AUTHOR]

The effects of different surface finishing procedures on the translucency of yttria stabilized zirconia ceramics (ZrO 2) were evaluated. ZrO 2 -3mol.%Y 2 O 3 (designed Zr3) or ZrO 2 -5mol.%Y 2 O 3 (Zr5) specimens with thickness varying between 0.5 and 1.5 mm were obtained by sintering at 1500 °C for 2 h. Surface finishing of the sintered specimens was done in three distinct manners: polishing with diamond pastes, blasting with Al 2 O 3 particles and blasting with Al 2 O 3 –SiO 2 particles, according to the preparation protocol for dental prostheses. These sample groups were characterized by X-Ray diffraction analysis, scanning electron microscopy, surface roughness and spectrophotometry. The sintered ceramics exhibited relative densities higher than 99% and were composed of 68.5% and 31.5%of tetragonal (t)-ZrO 2 and cubic(c)-ZrO 2 for composition Zr3 and 25.2% and 74.8% for composition Zr5, respectively. Furthermore, 1.5 to 1.8% of monoclinic (m)-ZrO 2 , has been found in the blasted surfaces. The average grain size varied from 0.5 μm for Zr3 to 1.45 μm for the Zr5 samples. After polishing, all samples presented a surface roughness R a of about 0.05 μm, while blasting resulted in an increased roughness ranging between 1.24 μm and 1.49 μm.Samples rich in (c)-ZrO 2 phase (Zr5) are more translucent than samples rich in (t)-ZrO 2 (Zr3) because of their larger grain size and because the cubic phase is less anisotropic than (t)-ZrO 2. Furthermore, the translucency of thinner samples is more affected by abrasive blasting because they also present the highly anisotropic monoclinic(m)-ZrO 2 phase and, therefore, the reduction of translucency is more pronounced. Parameters such as grain size, crystalline phase composition, porosity and grain boundary density are used to explain the phenomena involved in the differences of translucency of these materials. [ABSTRACT FROM AUTHOR]

The aim of this systemic review, conducted in accordance with the PRISMA statement, was to investigate the impact of surface pretreatments on the bonding strength of high performance polymers (HPPs). Eight databases were searched through March 2019. Risk of bias was assessed and random effects meta-analyses were applied to analyze mean differences in shear bond strength (SBS) and tensile bond strength (TBS), considering surface pretreatments and bonding agents after 24h and thermocycling. A total of 235 relevant titles and abstracts were found, yielding 11 final selections. Low risk of bias was observed in most studies. For polyetheretherketone (PEEK) specimens, random-effect models showed that, compared to non-treated controls, pretreatments associated with Visio.link® (Bredent, Senden, GE) increased TBS by 26.72 MPa (95% confidence interval (CI), 19.69–33.76; p < 0.00001) and increased SBS by 4.86 MPa (95% CI, 2.61–7.10; p < 0.00001). Air abrasion improved SBS by 4.90 MPa (95% CI, 3.90–5.90; p < 0.00001) (50 μm alumina) and 4.51 MPa (95% CI, 1.85–7.18; p = 0.0009) (silica-coated CoJet). In comparison to non-treated controls, Visio.link® and Signum PEEK Bond® (Heraeus Kulzer, Hanau, GE) increased SBS by 33.76 MPa (95% CI, 18.72–48.81; p < 0.00001) and 33.28 MPa (95% CI, 17.48–49.07; p < 0.00001), respectively. No differences were found between Visio.link® and Signum PEEK Bond® or Monobond Plus/Heliobond® (Ivoclar Vivadent, Schaan, LH) (p > 0.05). Similar results were observed for polyetherketoneketone (PEKK) specimens. This review shows improved HPP bonding following the application of various surface pretreatments, including air abrasion and bonding agents. [ABSTRACT FROM AUTHOR]

Burrs, being one of the most undesired obstructions generated during machining, affects work piece quality negatively in many aspects. Although deburring removes burrs, this extra process is time consuming, costly and might affect dimensional accuracy. This study investigates mechanisms, effects and variations on burr formation in most common machining processes such as drilling, milling, turning and grinding based on the information available in literature. The problems related to burrs as well as ways and methods to remove burr and control or minimize burr formation has critically discussed. Burrs can be minimised by selecting proper tool geometry, tool materials, coolant, machining parameters, work piece material, process planning and tool path design. As there is no method that can eliminate burr formation, thus deburring is essential to eliminate burrs after machining. Manual tools, abrasive blasting, abrasive flow, magnetic abrasive finishing, centrifugal barrel finishing, thermal melting and electrochemical effect are most commonly used for deburring depending on material, size and precision of parts. [ABSTRACT FROM AUTHOR]

Abrasive jet micro-machining (AJM) uses compressed air carrying abrasive solid particles to micro-machine a variety of features into surfaces. If the feature sizes are less than the size of the abrasive jet footprint, then a patterned erosion-resistant mask is used to protect the substrate material, leaving exposed areas to define the features. Previous investigations have revealed a 'blast lag' phenomenon in which, for the same dose of abrasive particles, narrower mask openings lead to channels that are shallower than wider ones. Blast lag occurs when using AJM on brittle substrates because of the natural tendency to rapidly form a V-shaped cross-sectional profile which inhibits abrasive particle strikes on the narrow vertex at the feature centerline. In this paper, the blast lag phenomenon is studied when using AJM to machine a network of microfluidic channels. It is found that, in some cases, differences in blast lag occurring at channel intersections and within the channels themselves, can lead to channel networks of nonuniform depth. A previously developed surface evolution model is adapted to allow prediction of the onset of blast lag in the channels and intersections and thus explain these differences. Finally, methods to eliminate the differences are discussed. • Blast lag between channel intersections and channel themselves have been reported. • The blast lag decreased when the width increased, and the particle size decreased. • Absolute blast lag was slightly greater in T-intersections than cross-intersections. • Developed a model which can be used to predict the onset of blast lag. [ABSTRACT FROM AUTHOR]

Background: Pits and Fissures are recognized as being highly susceptible to caries. Pit and fissure sealants are one of the best methods of preventing caries as it occludes the fissures and pits from the accumulation of plaque and cariogenic microflora. There are different methods of cleaning and preparing occlusal pits and fissures for preventing caries which helps in alleviating oral health status of paediatric population.Aim: The aim of the present study was to evaluate and compare the microleakage of pit and fissure sealants after using five different preparation techniques, namely: A) Conventional technique using pumice prophylaxis, B) enameloplasty with round carbide bur, C) enameloplasty with fissurotomy bur, D) air polisher, and E) air abrasion.Materials and Methods: The study was conducted on 50 caries-free premolars extracted for orthodontic purpose. These teeth were randomly assigned to five groups, 10 teeth in each for receiving fissure sealant after different surface preparation; thermocycling and sectioning of samples were performed and microleakage was assessed under a stereomicroscope after methylene blue dye immersion.Results: The results of air abrasion groups were significantly superior with "0" microleakage when compared to all other groups followed by round bur, fissurotomy bur, air polisher and pumice prophylaxis.Conclusion: To improve the marginal adaptation of the sealants, minimally invasive methods are the most favoured methods of occlusal preparation. This study promises to show positive results for fissure sealants which are likely to play an important role in caries prevention and techniques that are intended to protect caries susceptible surfaces. [ABSTRACT FROM AUTHOR]

The parameters of abrasive blasting process directly affect the condition of the metal surface, changing the degree of surface roughness and wettability, depending on the size of the used particle, the pressure or type of abrasive. The aim of this study was to analyze the condition of Ni-Cr alloy surface after abrasive blasting using various process variants. The samples were blasted by Al2O3 abrasive using various particle sizes and pressures of the process. Basic and specific roughness parameters were investigated, and a surface wettability test was performed, and the percentage share of abrasive particles penetrated in the surface after abrasive blasting was also examined. The most considerable differences in the condition of the surface were observed with the change in the particle size of Al2O3. Statistical analysis confirmed the statistical significance of all these relationships. [ABSTRACT FROM AUTHOR]

The effects of blasting with metallic steel grit and non-metallic alumina grit on steel surface characteristics were evaluated. These abrasives are generally used at construction sites and in vacuum blasting. Milled steel specimens were used to investigate the effect of the blasting conditions on surface properties. The effect of difference in surface properties on the adhesion strength and corrosion behavior were measured through adhesion tests, polarization curves, and electrochemical impedance spectroscopy. The limitations of blasting were evaluated using corroded steel specimens, as were the effects of corrosion products, salts, and abrasive material remaining on the blasted steel surface on the adhesion and corrosion resistance of paint. Steel grit more effectively increased the surface roughness than alumina grit; however, with both abrasive materials, the roughness increased with the blast projection angle. However, in the case of alumina grit, some abrasive material remained on the surface; thus, the actual roughness not including the residual abrasive material was more complex and greater than that of the sample blasted with steel grit. According to the adhesion strength test of painted and unpainted specimens, the adhesion force improved with increasing surface roughness and residual abrasive materials. Further, surface roughness was linearly correlated with the adhesion strength of unpainted specimens for both abrasive materials with blasting, and the adhesion strength force with alumina grit was approximately 1.4 times higher than that with steel grit, suggesting that increased roughness and residual abrasive material could benefit adhesion. According to the electrochemical test results, lower roughness and increased residual abrasive material owing to alumina grit on the steel surface enhanced the surface corrosion resistance, confirming the benefit of residual materials. Grinding left behind corrosion products and salts under the steel, resulting in the recurrence of rusting. However, the residue from blasting with alumina suppressed corrosion, thus improving the adhesion and corrosion resistance of the paint.

Background: Implant surface roughness after air abrasive therapy has not been measured precisely in previous research. Debridement with air abrasion facilitates the mechanical removal of bacterial biofilms but may damage implant surfaces on a microscopic level. Purpose: This study aimed to investigate the cleaning potential of various air abrasive powders and their effect on titanium implant surfaces. Materials and Methods: Twenty implants coated with red ink were inserted into three‐dimensional printed circumferential bone defect models. Treatment was completed with three types of air abrasive powders: sodium bicarbonate (SB), glycine, and erythritol for 60 seconds. Water alone was used as control. The percentage of remaining ink was assessed using digital photography and graphic software. Implant surface topography/roughness was quantified using optical profilometry and examined via scanning electron microscopy. The microscopic analysis was performed at two implant areas: collar (Laser‐Lok surface) and threads. Results: The cleaned surfaces (%, mean ± SD) after treatment with SB, glycine, and erythritol accounted for 49.3 ± 3.6%, 33.1 ± 1.2%, and 25.1 ± 0.7%, respectively. Statistically significant differences were found between all groups (P <.001). SB was the only powder that significantly increased the implant roughness (Sa) on both the implant collar (1.53‐2.10 μm) and threads (3.53‐4.20 μm). Regardless of the abrasive powder used, the collar, emerging implant surfaces from the defect base, and surfaces beneath implants threads exhibited more post‐treatment residual ink. Conclusion: Large‐sized powder showed the greatest cleaning capacity, but caused more alterations to the implant surface. Glycine and erythritol displayed no significant changes in surface roughness, however, demonstrated a limited ink removal capacity. [ABSTRACT FROM AUTHOR]