Residual Alumina Research Articles

The Biological Impact of Residual Aluminum Particles on Sand-Blasted Dental Implant Surfaces: A Systematic Review of Animal Studies

(1) Background: The use of alumina particles for surface treatment of dental implants is a common practice aimed at enhancing osseointegration. However, the biological effects of residual alumina particles on implant surfaces remain a subject of debate. This systematic review evaluates the impact of residual alumina particles on the osseointegration, biocompatibility, and bacterial adhesion of dental implants based on available in vivo experimental animal studies. (2) Methods: A comprehensive literature search was conducted across PubMed, Web of Science, and Scopus to identify relevant studies. The inclusion criteria focused on experimental animal studies that assessed the biological effects of alumina-blasted dental implants. Data extraction was carried out, and quality assessments were performed using the SYRCLE risk-of-bias tool. (3) Results: Ten studies met the inclusion criteria, involving various animal models, such as rabbits, pigs, dogs, and sheep. The findings demonstrated that residual alumina particles did not negatively impact osseointegration. Some studies reported accelerated bone growth and improved osseointegration with residual alumina. Additionally, residual alumina showed potential bactericidal properties, reducing bacterial adhesion. (4) Conclusions: The available evidence from animal studies suggests that residual alumina particles do not adversely affect the osseointegration and biocompatibility of dental implants. These particles may even enhance bone growth and reduce bacterial adhesion. However, due to the scarcity of human studies and the impracticality of histological assessments in humans, further research, including long-term clinical trials, is necessary to confirm these findings.

Effects of modified coal gasification fine slag on the processing and mechanical properties of natural rubber composites

AbstractCoal gasification fine slag (CGFS) is rich in unburned residual carbon, silica and alumina, and has a large specific surface area, making it a potential polymer‐reinforcing filler. Tea polyphenol (TP)‐modified coal gasification fine slag (TP‐CGFS‐T) was prepared using flotation and modification methods in this study. The effects of unmodified and modified CGFS‐T on the sulfurization performance, processing properties, thermal stability, fracture morphology, and mechanical properties of natural rubber composite materials were investigated. Results indicated that after TP modification, CGFS‐T exhibited highly uniform dispersion on the surface without the agglomeration of fillers. When the dosage of TP‐CGFS‐T was 20 phr, the comprehensive performance of the natural rubber (NR) composite material was optimal, with a tensile strength of 12.12 MPa, the elongation at break of 1208.83%, the tear strength of 30.94 kN/m, and the shore hardness of 38.7 A. As the amount of TP‐CGFS‐T increased, the scorch time of NR increased, which enhanced the processing safety of rubber. This study provides a strategy for treating CGFS, which can both reduce the pollution caused by CGFS and save costs for NR composite materials.Highlight The CGFS is separated into concentrate and tailings by flotation. The compatibility between fillers and the matrix is enhanced by TP modification of CGFS‐T. The composite materials show excellent mechanical and processing properties.

Factors That Influence Base-Catalyzed Thiol-Ene Hydrogel Synthesis.

Injectable, localized drug delivery using hydrogels made from ethoxylated trimethylolpropane tri-3-mercaptopropionate (ETTMP) and poly(ethylene glycol) diacrylate (PEGDA) has shown great potential due to these hydrogels' ability to exhibit non-swelling behavior and tunable drug release properties. However, current synthesis methods in the literature suffer from poor ETTMP solubility in water, slow gelation times exceeding 20 min, and a lack of reproducibility. To address these limitations, we have developed a reliable synthesis procedure and conducted a sensitivity analysis of key variables. This has enabled us to synthesize ETTMP-PEGDA hydrogels in a polymer concentration range of 15 to 90 wt% with gelation times of less than 2 min and moduli ranging from 3.5 to 190 kPa. We overcame two synthesis limitations by identifying the impact of residual mercaptopropionic acid and alumina purification column height on gelation time and by premixing ETTMP and PEGDA to overcome low ETTMP solubility in water. Our ETTMP-PEGDA mixture can be stored at -20 °C for up to 2 months without crosslinking, allowing easy storage and shipment. These and previous results demonstrate the potential of ETTMP-PEGDA hydrogels as promising candidates for injectable, localized drug delivery with tunable drug release properties.

In situ polymerization of ethylene with functionalized multiwalled carbon nanotubes using a zirconocene aluminohydride system in solution

AbstractThis study reports nanocomposite synthesis based on high‐density polyethylene with carbon nanotubes through in situ polymerization by coordination, and the use of an aluminohydride zirconocene/MAO system as a catalyst. Nanocomposites of linear polyethylene exhibit higher molar masses than pure high‐density polyethylene synthesized under similar conditions; where multiwalled carbon nanotubes (MWCNTs) acted as nucleating agents, shifting the crystallization temperature to higher values than neat high‐density polyethylene. Well‐dispersed MWCNTs in the HDPE matrices of the obtained nanocomposites are observed by SEM, where most of the nanocomposites showed an improvement in their thermal stability and electric conductivity, besides it is possible to obtain nanocomposites containing up to 41 wt% of nanofiller in the polymeric matrix. The aluminohydride complex n‐BuCp2ZrH3AlH2, activated with MAO at Al/Zr ratios of 2000, produced homogeneous HDPE/MWCNT composites under in situ polymerization conditions, at 70°C and 2.9 bar of ethylene pressure, with minimal residual alumina in the HDPE matrix.

Hydrothermal preparation of lightweight calcium silicate powder from alumina-leaching residue of low-calcium sintering red mud

In order to realize the complete and high-value utilization of red mud, a hydrothermal process was proposed to prepare the lightweight calcium silicate powder from a sodium calcium silicate residue after alumina extraction. The synthesized products were characterized by XRD, XRF, SEM, EDS, and PSD, and the corresponding transition mechanism and physical properties were also studied. The main silicon- and aluminum-bearing phases in the clinker after the low-calcium sintering are Na2CaSiO4 and NaAlO2, and the former silicate keeps stable during the alumina leaching process under atmospheric pressure. In the hydrothermal process, Na2CaSiO4 in the alumina-leaching residue is converted into NaOH and Ca5Si6O16(OH)2·4H2O in the alkali solution, and the residual alumina is converted into Ca3Al2SiO8·4H2O which promotes the generation of Ca5Si6O16(OH)2·4H2O. Increasing the reaction temperature, duration and liquid-solid ratio of the hydrothermal process can facilitate the alkali removal efficiency in calcium silicate powder and decrease its bulk density, while the excessive hydrothermal temperature and duration reduce the alkali removal efficiency. The Na2O residue and bulk density of the calcium silicate powder are 0.42% and 0.30 g·cm−3 obtained at the optimal hydrothermal conditions. The flaky particles of Ca5Si6O16(OH)2·4H2O are aggregated into a porous cauliflower structure, which improves the absorption and insulation properties of calcium silicate powder.

Benefits of Residual Aluminum Oxide for Sand Blasting Titanium Dental Implants: Osseointegration and Bactericidal Effects.

Objectives. The purpose of this work was to determine the influence of residual alumina after sand blasting treatment in titanium dental implants. This paper studied the effect of alumina on physico-chemical surface properties, such as: surface wettability, surface energy. Osseointegration and bacteria adhesion were determined in order to determine the effect of the abrasive particles. Materials and Methods. Three surfaces were studied: (1) as-received, (2) rough surface with residual alumina from sand blasting on the surface and (3) with the same roughness but without residual alumina. Roughness was determined by white light interferometer microscopy. Surface wettability was evaluated with a contact angle video-based system and the surface free energy by means of Owens and Wendt equation. Scanning electron microscopy equipped with microanalysis was used to study the morphology and determine the chemical composition of the surfaces. Bacteria (Lactobacillus salivarius and Streptococcus sanguinis) were cultured in each surface. In total, 110 dental implants were placed into the bone of eight minipigs in order to compare the osseointegration. The percentage of bone-to-implant contact was determined after 4 and 6 weeks of implantation with histometric analysis. Results. The surfaces with residual alumina presented a lower surface free energy than clean surfaces. The in vivo studies demonstrated that the residual alumina accelerated bone tissue growth at different implantation times, in relation to clean dental implants. In addition, residual alumina showed a bactericidal effect by decreasing the quantity of bacteria adhering to the titanium. Conclusions. It is possible to verify the benefits that the alumina (percentages around 8% in weight) produces on the surface of titanium dental implants. Clinical relevance. Clinicians should be aware of the benefits of sand-blasted alumina due to the physico-chemical surface changes demonstrated in in vivo tests.

Microstructural study of HVOF sprayed Ni particles on a grit-blasted stainless-steel substrate

Ni feedstock particles were sprayed onto a grit-blasted stainless-steel substrate using the high-velocity oxy-fuel (HVOF) deposition process to analyse the flattening behaviour and bonding features of single splats on a roughly textured substrate surface. Both substrate surface features and splat morphologies were analysed through scanning electron microscopy (SEM), while cross-sectional features, including the nature of the splat-substrate interface, were characterised through focused ion beam (FIB) microscopy and transmission electron microscopy (TEM). The chemistry of both the splat and substrate were analysed by energy-dispersive X-ray spectroscopy (EDS) interfaced to both the SEM and TEM. It was observed that despite the surface roughness, fully melted splats demonstrated good flattening performance, as well as efficient bonding, with the substrate surface. Such bonding was revealed through elemental interdiffusion across the splat-substrate interface. The particle size and the location of impact on the rough surface played important roles in defining the melting state, flattening degree and, ultimately, adhesion of the particles. Fully melted splats derived from smaller feedstock particles demonstrated good flattening behaviour, comparable to that observed on polished surfaces. Such particles exhibited better bonding efficiency than the partially melted splats, which originated from relatively larger feedstock particles. The presence of residual alumina contaminants, retained after grit blasting, is also analysed and discussed.

Critical evaluation of voltammetric techniques for antioxidant capacity and activity: Presence of alumina on glassy-carbon electrodes alters the results

Voltammetric techniques have been widely applied to determine the food antioxidant capacity/activity using different electrochemical parameters (peak current, peak potential, charge) and by calculating the electrochemical index (EI) using glassy-carbon electrodes (GCE). A crucial step in this analysis involves electrode cleaning that typically involves polishing of the GCE surface on alumina slurry. Probably because this procedure is well established, many works have not mentioned how residual alumina is efficiently removed after polishing, which suggests that alumina residues may be present on the GCE surface. This work demonstrates that residual alumina on GCE affects the electrochemical parameters of antioxidants (caffeic acid, gallic acid, chlorogenic acid, catechin, rutin and quercetin) and food samples (tea and wine) resulting in misleading results. We critically compare the responses of unmodified (properly cleaned) with alumina-modified GCE. The results obtained by cyclic voltammetry, differential-pulse voltammetry and square-wave voltammetry showed substantial current (and charge) increase on alumina-modified electrodes and the calculated EI was dramatically increased. Alumina immobilized on GCE likely provides adsorption sites that change the electrochemical oxidation pathway of phenolic antioxidants and may adsorb the antioxidant species or their intermediates facilitating the electron transfer between antioxidants and GCE. This explanation was evidenced by the change of the rate-determining step of the electrochemical oxidation of all antioxidants after alumina modification from diffusion-controlled to adsorption-controlled processes. The enhanced detectability provided by alumina may suggest the GCE modification for improved determination of the antioxidant capacity and activity. Considering this possibility, inter- and intra-electrode precision were evaluated and RSD values lower than 5% confirms the feasibility of the alumina-modified GCE for this purpose. On the other hand, this work highlights the need for proper electrode cleaning when a bare GCE is used for this aim.

A clean process for alumina extraction and ferrosilicon alloy preparation from coal fly ash via vacuum thermal reduction

Abstract Owing to high content of alumina in coal fly ash (CFA), recovering alumina from CFA has gained great interest from governments and scientists in recent years. With the aim of further reducing the cost as well as protecting the environment, a clean process to recover alumina and simultaneously produce ferrosilicon alloy from CFA by a vacuum technology was suggested in this paper. The overall process was composed of vacuum thermal reduction, sieving and magnetic separation. Thermodynamic calculations indicated that the initial decomposition temperature of stable mullite in CFA can decrease from 1367 to 1023 K as the CO partial pressure drops from 1 to 0.001 atm. The experimental results also proved that a vacuum environment can promote the mullite to decompose at a lower temperature. Simultaneously, the formation temperature of ferrosilicon alloys decreased greatly with using the vacuum thermal reduction. The produced ferrosilicon alloys and the residual alumina in reduced samples could be separated effectively in subsequent sieving and magnetic separation processes, and the separation efficiency depended not only on the reduction temperature, but also on the reduction duration. As the reaction temperature was 1473 K and the reduction duration was 6 h, the recovery rate of alumina reached 82.61%, and the content of alumina in the non-magnetic portion was 87.02%. Compared with the traditional route of alumina extraction, e.g., lime stone sinter process, there was almost no waste slag produced by vacuum thermal reduction process. Therefore, this provides a new idea for the environmentally friendly utilization of CFA.

Corrosion-Induced Mass Loss of Cu9Al4 at the Cu-Al Ball–Bond Interface: Explained Based on Full Immersion of Cu, Al, and Cu-Al Intermetallic Galvanic Couples

The disappearance of Cu9Al4 has been observed at the failed Cu-Al ball–bond interface in the standard humidity reliability test. Galvanic corrosion has been considered as the cause of the bond failure, yet no convincing argument has been provided to explain the preferential attack on Cu9Al4. Due to encapsulation, corrosion should proceed with the thin-layer electrolyte condition. The high ohmic resistance may constrain the galvanic corrosion between adjacent entities only. Thus, in this study, the galvanic corrosion between Cu and Cu9Al4, Cu9Al4 and CuAl2, and CuAl2 and Al were investigated using the zero-resistance ammetry. The results showed that the galvanic corrosion rate was the highest for the Cu9Al4-CuAl2 couple as compared with the other two galvanic couples. Also, the observed residual alumina between Cu9Al4 and CuAl2 and the associated internal stress build-up during the CuAl2-to-Cu9Al4 transition contributed to a higher crack propagation rate. Therefore, the failure first occurs at this interface. This failure then leads to a separation of Cu and Cu9Al4 from CuAl2 and Al. For the Cu-Cu9Al4 couple, Cu9Al4, the anode should corrode significantly faster due to the strong galvanic effect imposed by a larger surface area of Cu. In contrast, for the CuAl2-Al couple, the anodic corrosion rate of Al is slow as the galvanic effect imposed by the CuAl2 cathode is weak due to the small cathode surface area. As a result, Cu9Al4 disappeared from the failed ball–bond interface.

State of the Art Control Measures for Aluminium Fade and SEN Clogging during Steelmaking Operations

Crack formation, fatigue failure of components and other process interruptions in liquid steel practices such as ladle nozzle clogging, SEN clogging, break outs are mainly due to residual deoxidation products such as alumina present in steels. The present paper deals with the issues in steel processing operations and provides state-of-the-art control measures for clean steel production. Investigations regarding the residual alumina content and its consequences at integrated steel plant shows that, Al-fade of maximum 0.02% is observed, which produces equivalent of 37 Kg of alumina in the liquid steel. Furthermore, slag carry over, re-oxidation, improper argon rinsing practice, aluminium consumption at secondary steelmaking practices also influences the alumina formation during steelmaking practices. The residual alumina not only affects the quality of steel, but also results in process interruptions such as ladle choking, SEN choking, subsequent break outs etc. various steelmaking practices influences clogging and aluminium fade are discussed and possible suggestions are given to improve the cleanliness of steel.

Microstructure and mechanical properties of in-situ grown mullite toughened 3Y-TZP zirconia ceramics fabricated by gelcasting

In-situ grown mullite toughened zirconia ceramics (mullite-zirconia ceramics) with excellent mechanical properties for potential applications in dental materials were fabricated by gelcasting combined with pressureless sintering. The effect of sintering temperature on the microstructure and mechanical properties of mullite-zirconia ceramics was investigated. The results indicated that the columnar mullite produced by reaction was evenly distributed in the zirconia matrix and the content and size of that increased with the increase of sintering temperature. Mullite-zirconia ceramics sintered at 1500°C had the optimum content and size of the columnar mullite phase, generating the excellent mechanical properties (the bend strength of 890.4MPa, the fracture toughness of 10.2MPa.m1/2, the Vickers hardness of 13.2GPa and the highest densification). On the other hand, zirconia particles were evenly distributed inside the columnar mullite, which improved the mechanical properties of columnar mullite because of pinning effect. All of this clearly confirmed that zirconia grains strengthened columnar mullite, and thus the columnar mullite was more effective in enhancing the zirconia-based ceramics. Simultaneously, the residual alumina after reaction was distributed evenly in the form of particle, which improved the mechanical properties of the sample because of pinning effect. Overall, the synergistic effect of zirconia phase transformation toughening with mullite and alumina secondary toughening improved the mechanical properties of zirconia ceramics.

Bonding effectiveness of self-adhesive and conventional-type adhesive resin cements to CAD/CAM resin blocks. Part 2: Effect of ultrasonic and acid cleaning.

The present study assessed the effect of ultrasonic and acid cleaning on resin cement bonding to CAD/CAM resin blocks. One of two resin cements, PANAVIA V5 (PV5) or PANAVIA SA CEMENT HANDMIX (PSA), were bonded to one of 24 CAD/CAM blocks (KATANA AVENCIA BLOCK). Each cement group was divided into four subgroups: no cleaning (Ctl), ultrasonic cleaning (Uc), acid cleaning (Ac) and Uc+Ac. Micro-tensile bond strengths (µTBSs) were measured immediately and 1, 3, and 6 months after water storage. Block surfaces after each treatment were analyzed by scanning electron microscopy. Analysis of variance revealed a statistically significant effect for the parameters 'surface treatment' (p<0.001, F=40), 'resin cement' (p<0.001, F=696) and 'water aging' (p<0.001, F=71). The PV5 group exhibited higher µTBS values than the PSA group. Although cleaning after sandblasting was effective in removing residual alumina particles, it did not affect the long-term bonding durability with non-contaminated CAD/CAM resin blocks.

The Effect of Composition on the Optical Properties and Hardness of Transparent Al‐rich MgO·nAl2O3 Spinel Ceramics

The study investigates the transmittance and hardness of Al‐rich spinel ceramics (MgO·nAl2O3, 1 ≤ n ≤ 2.5) prepared by reaction air sintering (up to closed porosity) of different ratios of fine and coarse‐grained commercial Al2O3 and MgO raw powders completed by subsequent hot isostatic pressing (HiP). Different compositions give rise to a wide range of presintering temperatures. With starting compositions 1 ≤ n ≤ 1.5, presintering results in a formation of single‐phase spinel, in which the excess of Al is solved. With higher Al contents (n &gt; 1.5), however, a biphasic ceramic of stoichiometric MgAl2O4 and residual alumina is formed first. This excess alumina is incorporated into the spinel lattice during the final HiP at a temperature of 1750°C. Single‐phase, highly transparent spinel is obtained by increasing the Al‐content up to n = 2.5, which gives about 85% in‐line transmittance in the visible range of light and about 63% at a UV wavelength of 200 nm. Whereas the optical properties can be improved, the hardness (HV1) slightly decreases with increasing Al content. Depending on the raw powders, the hardness of samples prepared by finer powders tend to higher values enabled by the development of a bimodal microstructure with a finer grain fraction (≤2 μm) between coarser grains (≤156 μm). In contrast, samples made of coarser powders need higher sintering temperatures and exhibit, then, a monomodal microstructure of very large grains (≤622 μm) only.

Aluminum Deoxidation Equilibria in Liquid Iron: Part I. Experimental

In order to provide accurate information for refining of steel containing more than 1 mass pct Al, previously known information about Al deoxidation equilibria in liquid iron was critically reviewed. New Al deoxidation equilibria, Al and O contents in liquid iron in equilibrium with solid Al2O3 were measured at 1873 K and 1923 K (1600 °C and 1650 °C) over the whole Al composition range, 0.0027 < [pct Al] < 100. In order to secure the deoxidation equilibria, in the present study, the Al deoxidation experiments were carried out by employing three different methods: (1) traditional Al deoxidation by the addition of Al into Fe-O alloys, (2) oxidation of Al in Fe-Al alloys by the addition of Fe2O3 as an oxygen source, and (3) addition of CaO flux for an effective removal of suspended Al2O3 inclusions in liquid alloys containing high Al. In addition, in the present study, the O solubility limit in pure Al melt in equilibrium with solid Al2O3 was also measured in the temperature range from 1673 K to 1873 K (1400 °C to 1600 °C). The present experimental results provide a complete set of Al deoxidation equilibria in liquid iron which may be useful for the estimation of residual oxygen level and alumina inclusion formation in high Al steel processing. Interaction parameter formalism, which was originally proposed by Wagner and Chipman and has been widely used to interpret the Al deoxidation equilibria in liquid iron, was found to be inapplicable. Limitation of the interaction parameter formalism at high Al content in liquid Fe was discussed.

Smelter Fluoride Balances: The Interplay Between Alumina Phases, Pore Size Distributions, and the Impacts of Weather

Fluoride cycling within a smelter has been examined as a function of alumina properties. Using an experimental configuration in which the two ends of a single potline were operated with different aluminas, quantitative measurements were made of fluoride evolution from the pots, and hydrogen fluoride (HF) levels at the scrubber and stack. Correlations were then examined with specific alumina properties, once environmental factors and other baseline effects had been considered. Although the phase analysis, including both residual gibbsite and alumina structural hydroxide content, is correlated with HF generation, local weather conditions (primarily humidity) also have a major influence on fluoride evolution. Importantly, HF concentrations at the scrubber (measured in the gas phase at the outlet to the gas treatment center), as a proxy for the kinetics of the scrubbing process, support the importance of alumina pore size distribution as opposed to simply specific surface area. This is also found to be true in the independent analysis of bath acidity, indicating a more general but extremely important influence of alumina porosity on the entire fluoride cycle. The study provides insight into the impacts of a range of typically unreported alumina properties on smelter performance and strongly supports the presence of kinetically inaccessible porosity in pores narrower than ~3 nm in alumina.

Determination of Aluminum Oxide Concentration in Molten Cryolite-Alumina

A method is developed for determining alumina concentration in molten cryolite-alumina. The divergence between alumina concentration values, determined by the proposed method and by leaching AlCl3, is on average 1.5 wt.% Al2O3. It is established that the electrolyte melting temperature depends to a considerable extent on the current melt alumina concentration. Values are determined of specific influence coefficients for the content of AlF3, CaF2, MgF2, LiF, and Al2O3 in electrolyte on melt liquidus temperature. The method makes it possible to exclude errors connected with the residual insoluble alumina content within an electrolyte sample, due to the use of a device providing operational and precise determination of data required for calculating alumina concentration.

Investigations on phase constitution, mechanical properties and hydration kinetics of aluminous cements containing magnesium aluminate spinel

Abstract Aluminous cement containing magnesium aluminate (ACMA) spinel was prepared in situ by sintering mixtures of limestone, magnesia and bauxite. The phase constitution, micro-morphology, and hydration kinetics of ACMA were investigated by X-ray diffraction (XRD), scanning electron microscope (SEM) and isothermal calorimeter measurements, respectively. Magnesium aluminate (MA) spinel, calcium monoaluminate (CA) and calcium bialuminate (CA 2 ) are the primary phases of the obtained ACMA. In addition, trace amount of calcium silicoaluminate (C 2 AS) and residual alumina (Al 2 O 3 ) were detected. MA, mainly exists in the form of octahedron on the order of 2–5 μm and forms agglomerates with the tabular or flaky-shaped CA in the clinker. The compressive strength of the ACMA castables increased remarkably as a function of CA content. The measurement of hydration heat demonstrated a five stage hydration process, namely, pre-induction, induction, acceleration, deceleration and stabilization. The N value was calculated to be lower than 1 in acceleration stage which indicates a nucleation controlled hydration process. On the other hand, it was higher than 1 in stabilization stage showing a diffusion controlled process.

Microstructural Modification Arising from Alkaline Etching and Its Effect on Anodizing Behavior of Al-Li-Cu Alloy

Surface and near-surface microstructures of alkaline etched AA2099-T8 aluminum alloy have been characterized. The effect of alkaline etching on the anodizing behavior of the alloy in both acidic and neutral electrolytes has been investigated by comparing the electrochemical responses and the resultant anodic films of mechanically polished and alkaline etched alloys. It was revealed that alkaline etching could locally remove intermetallics from the alloy surface, with development of a copper-enriched layer immediately beneath a residual alumina film of about 5 nm thickness. The “footprints” of alkaline etching, i.e. the removal of intermetallics and the formation of copper-enriched layer during alkaline etching, could affect subsequent anodizing behavior of the alloy, particularly in the early stages. The removal of intermetallics from the alloy surface could not only improve anodizing efficiency but also contribute to reduced discontinuities in the resultant anodic films, potentially benefiting corrosion and fatigue resistances of the anodized profiles. The difference in anodizing behavior caused by the copper-enriched layer developed during alkaline etching was considered limited to the early stages of anodizing, since a similar copper-enriched layer could be formed quickly during subsequent anodizing process, regardless of the surface pre-treatment.

Effects of Surface Modifications with Oxalic Acid Etching and Sandblasting on Surface Topography and Biocompatibility of cpTi Surfaces

ABSTRACTThe objective of this study was to evaluate the topographical effects of titanium surfaces created by sandblasting and oxalic acid etching on the adhesion of human fetal osteoblast cells (CRL-11372) in vitro after 24 hours. Osteoblast cells were cultured on polished titanium (Ti) discs (Control Group), alumina (Al2O2) particle blasted and oxalic acid etched (20 min) Ti discs, oxalic acid etched polished Ti discs for 20 min, and oxalic acid etched Ti discs for 60 min. The topographies and roughness of the modified surfaces were assessed. Cell count, cell viability and morphologic differences between cells adhering to the modified surfaces were evaluated. The results showed that all surfaces, independent of surface roughness, favored cell adhesion with similar cell viabilities to that of the positive control group cells after 24 h. The highest Ra (average roughness) value was found for sandblasted and oxalic acid etched surfaces as 4.54 μm. Acid etching with 10 % oxalic acid after sandblasting did not eliminate residual alumina particles. Surface modification processes ended up with similar mean total cell counts with each other, even exhibiting no differences from the positive control group in terms of their cell viabilities. Oxalic acid etching and sandblasting surface treatments represented in our study increased the surface roughness values and allowed adhesion of the CRL-11372 cells after 24 h of incubation.