Acid Etching Treatment Research Articles

Effect of surface alkali-based treatment of titanium implants on ability to promote in vitro mineralization and in vivo bone formation.

Since success rate of dental implants might be challenged in bone of low density, an optimum implant surface characteristic is demanding. In this work, alkali treatment of Ti implants showed significant advantage of surface mineralization upon soaking in simulated body fluid. Using an in vivo rat model, Ti surfaces with either acid-etching treatment or alkali-based treatment evoked robust bone formation around Ti implants. Such information may be utilized for the advancement of biomaterials research for bone implants in future.

Acid etching of glass-infiltrated zirconia and its biological response.

PURPOSEThe purpose of this study was to evaluate the influence of acid etching treatment on surface characteristics and biological response of glass-infiltrated zirconia.MATERIALS AND METHODSA hundred zirconia specimens were divided into four groups depending on surface treatments: untreated zirconia (group Z); acid-etched zirconia (group ZE); glass-infiltrated zirconia (group ZG); and glass-infiltrated and acid-etched zirconia (group ZGE). Surface roughness, surface topography, surface morphology, and Vickers hardness of specimens were evaluated. For biological response test, MC3T3-E1 cell attachment and proliferation on surface of the specimens were examined. The data were statistically analyzed using one-way ANOVA and Tukey's HSD test at a significance level of 0.05.RESULTSGroup ZGE showed the highest surface roughness (Ra = 1.54 µm) compared with other groups (P < .05). Meanwhile, the hardness of group Z was significantly higher than those of other groups (P < .05). Cell attachment and cell proliferation were significantly higher in group ZGE (P < .05).CONCLUSIONWe concluded that effective surface roughness on zirconia could be made by acid etching treatment after glass infiltration. This surface showed significantly enhanced osteoblast cell response.

A new method for developing defect-rich graphene nanoribbons/onion-like carbon@Co nanoparticles hybrid materials as an excellent catalyst for oxygen reactions.

Herein, a novel material with an excellent electrocatalytic activity for the oxygen reduction reaction (ORR), composed of onion-like carbon@Co nanoparticles (NPs) incorporated on defect-rich N-doped graphene nanoribbons (C@Co-NGR), is prepared via a combination of nitric acid etching and subsequent high-temperature treatment of the as-synthesized C@Co-N doped carbon nanotubes. The as-prepared C@Co-NGR exhibits excellent electrocatalytic activity for the ORR in 0.10 M KOH with a half-wave potential of 0.830 V (vs. a reversible hydrogen electrode, RHE), which is 21 mV more positive than that of a commercial 20 wt% Pt/C catalyst. Moreover, it shows a higher stability and better methanol tolerance than the commercial Pt/C catalyst in alkaline solution, with almost no shift in the ORR polarization curve after 3000 cycles and no change of the ORR peak in the cyclic voltammogram in the presence of 1.0 M methanol. Most importantly, the C@Co-NGR also exhibits a comparable activity for the oxygen evolution reaction (OER) in 0.10 M KOH solution, in which the overpotential needed to achieve a current density of 10 mA cm-2 is 410 mV, comparable to that of the state-of-the-art commercial RuO2 catalyst (370 mV, vs. RHE). This makes the C@Co-NGR one of the best non-precious-metal catalyst for OER and ORR in alkaline solution ever reported.

Enhanced photocatalytic activity of micro/nano textured TiO2 surfaces prepared by sandblasting/acid-etching/anodizing process

In this study, micro-textured titanium surfaces were created by sandblasting and acid-etching methods. Nanostructured titanium dioxide (TiO2) films were synthesized on the micro-textured titanium surfaces by anodizing method. Subsequently, anodized (A), acid-etched/anodized (EA), sandblasted/anodized (SA) and sandblasted/acid-etched/anodized (SEA) samples were fabricated. Structural and morphological properties of the prepared samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and atomic force microscopy (AFM). Furthermore, surface roughness and wettability of the samples were evaluated by means of profilometry and contact angle measurement systems, respectively. Finally, the photocatalytic activities of the samples were determined by using aqueous methylene blue (MB) solutions under a specific UV light illumination for different periods of time. The obtained results pointed out that sandblasting and acid-etching treatment improved the surface roughness of the samples significantly. The photocatalytic experimental results showed that micro-textured surface accelerated the degradation of MB, if compared to samples which are anodized without any of the regarding surface treatments. To sum up, sandblasted/acid-etched/anodized titanium surfaces exhibited the highest wettability, surface roughness and photocatalytic activity among the samples. The present study may shed new light on the modification of titanium surfaces.

Growing and Etching MoS₂ on Carbon Nanotube Film for Enhanced Electrochemical Performance.

In this work we directly synthesized molybdenum disulfide (MoS2) nanosheets on carbon nanotube film (MoS2@CNT) via a two-step chemical vapor deposition method (CVD). By etching the obtained MoS2@CNT into 10% wt HNO3, the morphology of MoS2 decorated on CNT bundles was modulated, resulting in more catalytic active MoS2 edges being exposed for significantly enhanced electrochemical performance. Our results revealed that an 8 h acid etching sample exhibited the best performance for the oxygen evolution reaction, i.e., the current density reached 10 mA/cm2 under 375 mV over-potential, and the tafel slope was as low as 94 mV/dec. The enhanced behavior was mainly originated from the more catalytic sites in MoS2 induced by the acid etching treatment and the higher conductivity from the supporting CNT films. Our study provides a new route to produce two-dimensional layers on CNT films with tunable morphology, and thus may open a window for exploring its promising applications in the fields of catalytic-, electronic-, and electrochemical-related fields.

Fabrication of hierarchical micro/nanotopography on bio-titanium alloy surface for cytocompatibility improvement

Micro/nanotopographical modification of biomaterials plays an essential role in the improvement of implants’ cytocompatibility. In this paper, hierarchical micro/nanostructured surface was constructed to improve the titanium alloy cytocompatibility, which combined sandblasting, acid etching, and alkali heat treatment. The surface features were characterized using scanning electron microscope (SEM), laser scanning microscope, X-ray diffraction (XRD), and contact angle goniometer. A series of biological tests were carried out to evaluate cytocompatibility of bio-titanium alloy in vitro, including cell adhesion, counting, proliferation, osteocalcin expression, alkaline phosphatase (ALP) activity, and extracellular matrix mineralization. The results show that bio-titanium alloy with micro/nanostructured surface provided a beneficial interface which could promote the growth of osteoblasts. A uniform nanowire layer with high hydrophilicity was superposed on microstructures. Meanwhile, the biological tests indicate that hierarchical micro/nanostructures with micropits and nanowires could significantly promote osteoblasts’ initial adhesion, proliferation, and differentiation. Moreover, the underlying mechanism of interaction between implants and cells was also discussed. This work proposes an effective approach to fabricate micro/nanostructured surface on titanium alloy for cytocompatibility improvement.

Synergistic effects of bioactive ions and micro/nano-topography on the attachment, proliferation and differentiation of murine osteoblasts (MC3T3).

Surface topography and chemical nature of biological materials play an important role in regulating cell behaviors. For the intention of improving the biological performance of Ti6Al4V, the hierarchical micro/nano-topographies containing bioactive ions (Ca(2+) and Mg(2+)) were fabricated in this study. Briefly, the hierarchical micro/nano-topography was constructed on Ti6Al4V surface via sandblasting, acid etching and alkali-hydrothermal treatment. Then Na(+) existing in the nano-topography was replaced by Ca(2+) and Mg(2+) through hydrothermal reaction. The surface topographies and chemical nature of native and treated samples were characterized using laser scanning microscope, X-ray Photoelectron Spectroscopy and field emission scanning electron microscopy with the energy-dispersive spectroscopy. Surface wettability was measured with a contact angle goniometer. A series of biological tests were carried out to evaluate the synergistic effects of bioactive ions and micro/nano-topography on the attachment, proliferation and differentiation of murine osteoblastic MC3T3 cells. The results of in vitro tests indicated that Ca(2+) and Mg(2+) in the titanium alloy surface had an affirmative effect on cells attachment, proliferation and differentiation. Cells grown onto micro/nano-structured surface with Ca(2+) implantation exhibited significantly higher differentiation levels of alkaline phosphatase activity and mineralization compared to that on micro/nano-structured surface with Mg(2+) implantation. This study provided a novel method to construct a favorable biological environment between tissues and implants.

Bioactivity of hybrid micro/nano-textured Ti-5Si surface by acid etching and heat treatment

The surfaces of the Ti-5Si specimens tested in this study displayed micro-pores and a nano-textured structure after being etched with a H2SO4 solution. After immersion in a simulated body fluid (SBF) solution for 7days, numerous apatite nucleation spheres were found on the outer and inner surfaces of the micro-pores after acid-etching and acid-heat treatments. Apatite precipitation was clearly observed on the surfaces of the Ti-5Si specimens without heat treatment, suggesting that heat treatment is not necessary for apatite precipitation on the surface of Ti-5Si that has undergone the acid etching process. Additionally, there was apatite formation on the surface of the as-cast Ti-5Si specimens that were soaked in SBF solution for 14days, although the ability of as-cast Ti-5Si alloy to form apatite was slightly lower than that of its acid-etched or acid-heat-treated counterparts. This acid treatment has the potential to enhance the bioactivity of Ti-5Si and is expected to be able to strengthen the fixation of the implant with bone through a hybrid micro/nano-textured surface. Therefore, it can be concluded that etching in sulfuric acid is an effective and simple surface treatment for Ti-5Si alloy destined for biological applications.

Surface-treated commercially pure titanium for biomedical applications: Electrochemical, structural, mechanical and chemical characterizations

Modified surfaces have improved the biological performance and biomechanical fixation of dental implants compared to machined (polished) surfaces. However, there is a lack of knowledge about the surface properties of titanium (Ti) as a function of different surface treatment. This study investigated the role of surface treatments on the electrochemical, structural, mechanical and chemical properties of commercial pure titanium (cp-Ti) under different electrolytes. Cp-Ti discs were divided into 6 groups (n=5): machined (M—control); etched with HCl+H2O2 (Cl), H2SO4+H2O2 (S); sandblasted with Al2O3 (Sb), Al2O3 followed by HCl+H2O2 (SbCl), and Al2O3 followed by H2SO4+H2O2 (SbS). Electrochemical tests were conducted in artificial saliva (pHs 3; 6.5 and 9) and simulated body fluid (SBF—pH7.4). All surfaces were characterized before and after corrosion tests using atomic force microscopy, scanning electron microscopy, energy dispersive microscopy, X-ray diffraction, surface roughness, Vickers microhardness and surface free energy. The results indicated that Cl group exhibited the highest polarization resistance (Rp) and the lowest capacitance (Q) and corrosion current density (Icorr) values. Reduced corrosion stability was noted for the sandblasted groups. Acidic artificial saliva decreased the Rp values of cp-Ti surfaces and produced the highest Icorr values. Also, the surface treatment and corrosion process influenced the surface roughness, Vickers microhardness and surface free energy. Based on these results, it can be concluded that acid-etching treatment improved the electrochemical stability of cp-Ti and all treated surfaces behaved negatively in acidic artificial saliva.

Application of reference point indentation for micro-mechanical surface characterization of calcium silicate based dental materials.

The objective of this study was to elucidate micromechanical properties of Biodentine and two experimental calcium silicate cements (CSCs) using Reference Point Indentation (RPI). Biomechanical characteristics of the cement type and the effects of a radiopacifier, liquid components, acid etching treatment and bioactivation in simulated body fluid (SBF) were investigated by measuring the microhardness, average unloading slope (Avg US) and indentation distance increase (IDI). Biodentine had a greater microhardness than the experimental CSCs, while the Avg US and IDI values were not significantly different among investigated materials. There was a statistically significant difference in microhardness and IDI values between pure CSCs and radiopacified cements (p < 0.05). Micromechanical properties were not affected by different liquid components used. Acid-etching treatment reduced Biodentine's microhardness while cements' immersion in SBF resulted in greater microhardness and higher IDI values compared to the control group. Clearly, the physiological environment and the cements' composition affect their surface micromechanical properties. The addition of calcium chloride and CSCs' immersion in SBF are beneficial for CSCs' micromechanical performance, while the addition of radiopacifiers and acid etching treatment weaken the CSCs' surface. Application of RPI aids with the characterization of micromechanical properties of synthetic materials' surfaces.

Osteogenic response and osteoprotective effects in vivo of a nanostructured titanium surface with antibacterial properties.

In implantology, as an alternative approach to the use of antibiotics, direct surface modifications of the implant addressed to inhibit bacterial adhesion and to limit bacterial proliferation are a promising tactic. The present study evaluates in an in vivo normal model the osteogenic response and the osteointegration of an anodic spark deposition nanostructured titanium surface doped with gallium (ASD+Ga) in comparison with two other surface treatments of titanium: an anodic spark deposition treatment without gallium (ASD) and an acid etching treatment (CTR). Moreover the study assesses the osteoprotective potential and the antibacterial effect of the previously mentioned surface treatments in an experimentally-induced peri-implantitis model. The obtained data points out a more rapid primary fixation in ASD and ASD+Ga implants, compared with CTR surface. Regarding the antibacterial properties, the ASD+Ga surface shows osteoprotective action on bone peri-implant tissue in vivo as well as an antibacterial effect within the first considered time point.

Calcium phosphate deposition on surface of porous and dense TiNi alloys in simulated body fluid

Porous and dense TiNi alloys were successfully fabricated by powder metallurgy (P/M) method, and to further improve their surface biocompatibility, surface modification techniques including grind using silicon-carbide (SiC) paper, acid etching and alkali treatment were employed to produce either irregularly rough surface or micro-porous surface roughness. X-ray diffractometry (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX) attached to SEM were used to characterize surface structure and the Ca-P coatings. Effects of the above surface treatments on the surface morphology, apatite forming ability were systematically investigated. Results indicate that all the above surface treatments increase the apatite forming ability of TiNi alloys in varying degrees when soaked in simulated body fluid (SBF). More apatite coatings formed on TiNi samples sintered at 1050° and 1100° due to their high porosity and pure TiNi phase that is beneficial to heterogeneous nucleation. Furthermore, more uniform apatite was fabricated on the sample sintered from the mixture of Ni and Ti powders.

Shear bond strength of veneering ceramic to coping materials with different pre-surface treatments.

PURPOSEPre-surface treatments of coping materials have been recommended to enhance the bonding to the veneering ceramic. Little is known on the effect on shear bond strength, particularly with new coping material. The aim of this study was to investigate the shear bond strength of veneering ceramic to three coping materials: i) metal alloy (MA), ii) zirconia oxide (ZO), and iii) lithium disilicate (LD) after various pre-surface treatments.MATERIALS AND METHODSThirty-two (n = 32) discs were prepared for each coping material. Four pre-surface treatments were prepared for each sub-group (n = 8); a) no treatment or control (C), b) sandblast (SB), c) acid etch (AE), and d) sandblast and acid etch (SBAE). Veneering ceramics were applied to all discs. Shear bond strength was measured with a universal testing machine. Data were analyzed with two-way ANOVA and Tukey's multiple comparisons tests.RESULTSMean shear bond strengths were obtained for MA (19.00 ± 6.39 MPa), ZO (24.45 ± 5.14 MPa) and LD (13.62 ± 5.12 MPa). There were statistically significant differences in types of coping material and various pre-surface treatments (P<.05). There was a significant correlation between coping materials and pre-surface treatment to the shear bond strength (P<.05).CONCLUSIONShear bond strength of veneering ceramic to zirconia oxide was higher than metal alloy and lithium disilicate. The highest shear bond strengths were obtained in sandblast and acid etch treatment for zirconia oxide and lithium disilicate groups, and in acid etch treatment for metal alloy group.

Facile method for preparing superoleophobic surfaces with hierarchical microcubic/nanowire structures

To facilitate the fabrication of superoleophobic surfaces having hierarchical microcubic/nanowire structures (HMNS), even for low surface tension liquids including octane (surface tension = 21.1 mN m−1), and to understand the influences of surface structures on the oleophobicity, we developed a convenient method to achieve superoleophobic surfaces on aluminum substrates using chemical acid etching, anodization and fluorination treatment. The liquid repellency of the structured surface was validated through observable experimental results; the contact and sliding angle measurements. The etching condition required to ensure high surface roughness was established, and an optimal anodizing condition was determined, as a critical parameter in building the superoleophobicity. The microcubic structures formed by acid etching are essential for achieving the formation of the hierarchical structure, and therefore, the nanowire structures formed by anodization lead to an enhancement of the superoleophobicity for low surface tension liquids. Under optimized morphology by microcubic/nanowire structures with fluorination treatment, the contact angle over 150° and the sliding angle less than 10° are achieved even for octane.

Osseointegration of titanium implants with SLAffinity treatment: a histological and biomechanical study in miniature pigs.

Electrochemical oxidation following sandblasting and acid-etching (SLA) treatment has received interest as a surface modification procedure for titanium (Ti) implants (denoted as an SLAffinity surface); however, little information is available on its impacts on the in vivo performance of SLAffinity-Ti implants. The present study evaluated the osseointegration and biomechanical bone-tissue response to SLAffinity-Ti implants with micro- and nanoporous oxide layers. The interaction between blood and the tested implants was examined. In total, 144 implants with the following surfaces were used: a standard machined (M-Ti), an SLA-Ti, and an SLAffinity-Ti surface. For each animal, four implants (one M-Ti, one SLA-Ti, and two SLAffinity-Ti) were inserted into the mandibular canine-premolar area for histomorphometric observations and another four implants were inserted into the flat surface on the anteromedial aspect of the rear tibia for removal torque (RT) tests. After 2, 4, and 8weeks of implantation, histomorphometric and RT tests were conducted. Interactions between blood and implants were better for implants with the SLAffinity-Ti surface. RT tests showed a significant improvement in fixation strength for SLAffinity-Ti implants (84.5 ± 8.7N-cm) after 8weeks compared to M-Ti (62.95 ± 11.5N-cm) and SLAffinity-Ti (76.1 ± 6.6N-cm) implants. A histological evaluation showed that osseous integration had occurred with all implants after 8weeks. SLAffinity-Ti implants exhibited 28.5 ± 6.2% bone-to-implant contact (BIC) at 2weeks and 84.3 ± 8.1% at 8weeks. M-Ti implants exhibited BIC levels of 17.0 ± 5.4 and 76.5 ± 6.3%, whereas SLA-Ti implants exhibited BIC levels of 28.5 ± 6.2 and 81.1 ± 8.4% at corresponding time intervals. In terms of the peri-implant bone area (BA), values for SLAffinity-Ti implants ranged from 29.5 ± 4.1 to 88.3 ± 3.0%. For M-Ti implants, values ranged from 20.3 ± 5.5 to 81.7 ± 4.2%. For SLA-Ti implants, values ranged from 23.0 ± 3.5 to 84.0 ± 3.6%. Electrochemical oxidation increased the oxide layers and improved the blood interaction with SLAffinity-Ti implants, resulting in significantly higher bone apposition with the SLAffinity-Ti implants after 2 and 8weeks of healing. An increase in resistance for the RT of SLAffinity-Ti implants over the 8-week healing period was also observed. The use of SLAffinity-Ti implants has potential for improvement of early osseointegration.

Gene expression profiling of bone marrow-derived stromal cells seeded onto a sandblasted, large-grit, acid-etched-treated titanium implant surface: The role of the Wnt pathway

ObjectiveThe physical and chemical characteristics of the titanium implant surface have been shown to influence dental implant fixation. However, the underlying mechanism by which sandblasted, large-grit, acid-etched (SLA) treatment affects osseointegration remains elusive. MethodsIn the present study, the involved target genes and pathways for SLA treatment, which is an extensively used implant surface modification on improving osseointegration, were identified by in vitro microarray and bioinformatics analyses. ResultsA total of 19 genes were differentially expressed after SLA treatment, which included Apc2, Fzd1, Frzb, Wnt16, Fzd2, Plau, Wnt5b, Wnt5a, Lrp6, Wnt9a, Sfrp4, Prkch, Calcoco1, Ccnd1, Wif1, Fzd4, Myc, LRP5, and Lect2. Interaction pathway analyses showed that the Wnt pathway was the most relevant signal after SLA treatment. To ensure the reliability of microarray data, LRP5 was shown to positively regulate osteogenic commitment, extracellular matrix synthesis, and mineralization for BMMSCs seeded onto an SLA-treated titanium surface. However, with LRP5 shRNA treatment, the reduction in calcium deposition in the SLA-treated group was more severe than that observed in cells seeded onto SLA-untreated titanium surface, suggesting that the function of LRP5 was reinforced in the SLA-treated group. In addition, the present study demonstrated that the β-catenin/LRP5 pathway was responsible for the enhanced osteogenic responses of BMMSCs on SLA-treated titanium surface. ConclusionsThe findings of the present study serve as an initial step towards understanding the mechanism underlying SLA treatment in osseointegration.

On the interfacial fracture resistance of resin-bonded zirconia and glass-infiltrated graded zirconia

ObjectiveA major limiting factor for the widespread use of zirconia in prosthetic dentistry is its poor resin-cement bonding capabilities. We show that this deficiency can be overcome by infiltrating the zirconia cementation surface with glass. Current methods for assessing the fracture resistance of resin-ceramic bonds are marred by uneven stress distribution at the interface, which may result in erroneous interfacial fracture resistance values. We have applied a wedge-loaded double-cantilever-beam testing approach to accurately measure the interfacial fracture resistance of adhesively bonded zirconia-based restorative materials. MethodsThe interfacial fracture energy GC was determined for adhesively bonded zirconia, graded zirconia and feldspathic ceramic bars. The bonding surfaces were subjected to sandblasting or acid etching treatments. Baseline GC was measured for bonded specimens subjected to 7 days hydration at 37°C. Long-term GC was determined for specimens exposed to 20,000 thermal cycles between 5 and 55°C followed by 2-month aging at 37°C in water. The test data were interpreted with the aid of a 2D finite element fracture analysis. ResultsThe baseline and long-term GC for graded zirconia was 2–3 and 8 times greater than that for zirconia, respectively. More significantly, both the baseline and long-term GC of graded zirconia were similar to those for feldspathic ceramic. SignificanceThe interfacial fracture energy of feldspathic ceramic and graded zirconia was controlled by the fracture energy of the resin cement while that of zirconia by the interface. GC for the graded zirconia was as large as for feldspathic ceramic, making it an attractive material for use in dentistry.

ChemInform Abstract: Review: Physico‐Chemical Modification as a Versatile Strategy for the Biocompatibility Enhancement of Biomaterials

AbstractReview: 131 refs.

Heterojunction Diodes and Solar Cells Fabricated by Sputtering of GaAs on Single Crystalline Si

This work reports fabrication details of heterojunction diodes and solar cells obtained by sputter deposition of amorphous GaAs on p-doped single crystalline Si. The effects of two additional process steps were investigated: A hydrofluoric acid (HF) etching treatment of the Si substrate prior to the GaAs sputter deposition and a subsequent annealing treatment of the complete layered system. A transmission electron microscopy (TEM) exploration of the interface reveals the formation of a few nanometer thick SiO2 interface layer and some crystallinity degree of the GaAs layer close to the interface. It was shown that an additional HF etching treatment of the Si substrate improves the short circuit current and degrades the open circuit voltage of the solar cells. Furthermore, an additional thermal annealing step was performed on some selected samples before and after the deposition of an indium tin oxide (ITO) film on top of the a-GaAs layer. It was found that the occurrence of surface related defects is reduced in case of a heat treatment performed after the deposition of the ITO layer, which also results in a reduction of the dark saturation current density and resistive losses.

A study on the performance of IrO2–Ta2O5 coated anodes with surface treated Ti substrates

Oxalic acid etching and hydrogen treatment were applied on Ti substrates of IrO2–Ta2O5 coated anodes. The coatings were prepared by thermal decomposition of a mixture of H2IrCl6·6H2O dissolved in hydrochloric acid and TaCl5 dissolved in alcohol. Surface morphology, microstructure, matter phase, electrochemical properties and accelerated life of the anodes were observed and examined. Compared with the anode without its substrate treated, the anodes with the substrates oxalic acid etched and hydrogen treated at 300°C, 400°C, 500°C and 600°C respectively show better electro-catalytic performance and longer life. However, effects of two methods are different. Oxalic acid etching of the substrate, which could get better improvement at accelerated life, while hydrogen treatment of the substrates, which could get better improvement at the electro-catalytic performance. Especially, anode with 400°C hydrogen treated substrate has the highest electro-catalytic activity.