Surface Topography Of Specimens Research Articles

The Effect of Chitosan Incorporation on Physico-Mechanical and Biological Characteristics of a Calcium Silicate Filling Material.

A tricalcium silicate-based cement, Biodentine™, has displayed antibiofilm activity when mixed with chitosan powder. This study aimed to assess the effect of chitosan incorporation on the physico-mechanical and biological properties of Biodentine™. In this study, medium molecular weight chitosan powder was incorporated into Biodentine™ in varying proportions (2.5 wt%, 5 wt%, 10 wt%, and 20 wt%). The setting time was determined using a Vicat apparatus, solubility was assessed by calculating weight variation after water immersion, radiopacity was evaluated and expressed in millimeters of aluminum, the compressive strength was evaluated using an Instron testing machine, and the microhardness was measured with a Vickers microhardness tester. In addition, surface topography of specimens was analyzed using scanning electron microscopy, and the effect of chitosan on the viability of human embryonic kidney (HEK 293) cells was measured by a colorimetric MTT assay. Incorporation of 2.5 wt% and 5 wt% chitosan powder delivered an advantage by speeding up the setting time of Biodentine material. However, the incorporation of chitosan compromised all other material properties and the crystalline structure in a dose-dependent manner. The chitosan-modified material also showed significant decreases in the proliferation of the HEK 293 cells, signifying decreased biocompatibility. Chitosan incorporation into calcium silicate materials adversely affects the physical and biological properties of the material. Despite the increased antimicrobial activity of the modified material, the diminution in these properties is likely to reduce its clinical value.

A Raman topography imaging method toward assisting surgical tumor resection

AbstractAchieving complete tumor resection upon initial surgical intervention can lead to better patient outcomes by making adjuvant treatments more efficacious and reducing the strain of repeat surgeries. Complete tumor resection can be difficult to confirm intraoperatively. Methods like touch preparation (TP) have been inconsistent for detecting residual malignant cell populations, and fatty specimens like breast cancer lumpectomies are too fatty to process for rapid histology. We propose a novel workflow of immunostaining and topographic surface imaging of freshly excised tissue to ensure complete resection using highly sensitive and spectrally separable surface-enhanced Raman scattering nanoparticles (SERS NPs) as the targeted contrast agent. Biomarker-targeting SERS NPs are ideal contrast agents for this application because their sensitivity enables rapid detection, and their narrow bands enable extensive intra-pixel multiplexing. The adaptive focus capabilities of an advanced Raman instrument, combined with our rotational accessory device for exposing each surface of the stained specimen to the objective lens, enable topographic mapping of complete excised specimen surfaces. A USB-controlled accessory for a Raman microscope was designed and fabricated to enable programmatic and precise angular manipulation of specimens in concert with instrument stage motions during whole-surface imaging. Specimens are affixed to the accessory on an anti-slip, sterilizable rod, and the tissue surface exposed to the instrument is adjusted on demand using a programmed rotating stepper motor. We demonstrate this topographic imaging strategy on a variety of phantoms and preclinical tissue specimens. The results show detail and texture in specimen surface topography, orientation of findings and navigability across surfaces, and extensive SERS NP multiplexing and linear quantitation capabilities under this new Raman topography imaging method. We demonstrate successful surface mapping and recognition of all 26 of our distinct SERS NP types along with effective deconvolution and localization of randomly assigned NP mixtures. Increasing NP concentrations were also quantitatively assessed and showed a linear correlation with Raman signal with an R2 coefficient of determination of 0.97. Detailed surface renderings color-encoded by unmixed SERS NP abundances show a path forward for content-rich, interactive surgical margin assessment.

Is Ammonium Hydrogen Difluoride a Solution for Zirconia Surface Conditioning?

This research investigated the topographical features and phase transformation of high-translucent monolithic zirconia after different surface conditioning methods. Zirconia slabs were divided into six groups according to surface treatment method. Group I: etched with hydrofluoric acid (HF); Group II: etched with an experimental acid solution (EAS); Group III: melt-etched with ammonium hydrogen difluoride (AHD); Group IV: air abrasion (AB); Group V: etched with EAS after air abrasion (AB+EAS); Group VI: melt-etched with AHD after air abrasion (AB+AHD). Surface topographies of specimens were documented by scanning electron microscopy (SEM). Tetragonal-to-monoclinic phase transformation was detected by X-ray diffraction and surface evaluation of zirconia specimens; surface roughness and contact angle measurements were performed. The data were statistically analyzed by the Kruskal- Wallis test and post hoc tests (P⟨0.05). The acid-etched zirconia groups (Group I, II, and III) showed the lowest contact angle and surface roughness values (P⟨0.05), while the air abrasion groups (Group IV, V, VI) showed the highest. The SEM images also supported these results. Within the limitations of this in vitro study, treating the monolithic zirconia surfaces with EAS or AHD after air abrasion may be recommended to alter the zirconia surfaces.

Effects of path accuracy on additively manufactured specimens by laser material deposition using six-axis robots

Additive manufacturing technologies such as laser material deposition (LMD) enable manufacturers to economically produce complex and individualized products. However, improved productivity and more economic use of LMD are necessary to benefit from these advantages in a wider range of applications. Through the use of industrial robots in LMD applications, large workspaces and geometric flexibility can be achieved at low cost. Possible effects of reduced path accuracies compared to conventional machines for LMD are not currently quantified. Initial studies suggest effects of path deviations on the component geometry. In this paper, an initial approach to investigate the influence of robot path deviations on the LMD component geometry is introduced. A novel approach toward correlation between path deviations of the robot and resulting surface waviness of the component is presented. The correlation is investigated on two different industrial robots with a powder-based LMD process. Tool center point (TCP) paths of the industrial robots are measured by means of a laser tracker. Robot TCP paths and resulting specimen surface topography are geometrically correlated and compared. The magnitude of the correlation is quantified by the calculation of the Pearson coefficient and a linear approximation of the correlation is made. In addition, the resulting correlation is checked by model calculations regarding the weld path formation as a function of the real tool paths with the aim of quantifying to what extent the waviness of the tool path is reflected in the waviness of the weld track.

Comparison of Resin Infiltration Technique with Conventional Preventive Applications on Occlusal Fissures in Terms of Chemical Analysis and SEM.

ObjectiveTo compare the subsurface mineral loss preventing capability of resin infiltration technique with topical fluoride and fissure sealant applications to demineralized occlusal fissures under simulated oral conditions.Materials and MethodsOcclusal surfaces of 64 extracted intact human third molars were demineralized. Next, the teeth were classified into four groups according to preventive applications (n = 16): G1, Specimens used as the control group with no preventive treatment; G2, Topical fluoride application (APF Gel/ DEEPAK); G3, Fissure sealant application (ClinproTMSealant/ 3M ESPE); and G4, Resin infiltration technique (Icon/ DMG). Chemical compositions before pH cycling were evaluated for eight specimens from each group. The remaining eight teeth from each group were subjected to pH cycling for 15 days to simulate the oral conditions. Subsequently, the specimens were fractured after immersion in liquid nitrogen and the subsurface fluoride (F), calcium (Ca), phosphorus (P) levels, and Ca/P ratio of each specimen were measured using energy dispersive x-ray spectrometer (EDS). The data were subjected to statistical analysis (p = 0.05). The effects of preventive applications to surface topography of specimens were evaluated using scanning electron microscope (SEM).ResultsThere were no significant differences among the groups in subsurface F, Ca, and P levels and Ca/P ratios before or after pH cycling (p > 0.05). All three preventive applications were effective during pH cycling according to SEM observations.ConclusionsThe subsurface mineral loss preventing capability of resin infiltration technique applied to occlusal fissures was comparable to topical fluoride and fissure sealant applications.Clinical significanceThe resin infiltration technique could represent a valid alternative to traditionally used both preventive and restorative treatments for treating initial carious lesions on occlusal fissures, offering the advantages of better resin penetration and retention.

Effect of Etching on Fatigue Properties of DD6 Single-Crystal Superalloy

The effects of etching on the surface integrities and the high cycle fatigue properties of DD6 single-crystal superalloy were investigated. The standard heat treated DD6 specimens were etched twice and four times using HCl/H2O2 solution, respectively, and the three-dimensional surface topography of specimens etched for different times was observed by Leica DCM8 confocal microscope and SEM. After that, the specimens with different surface states were subjected to high cycle fatigue testing at 760 °C and 980 °C in ambient atmosphere, respectively. The results showed that the surface of un-etched specimens had many longitudinal and parallel fine scratches which were caused by polishing, and the surface roughness was very low. Etching caused the occurrence of etching pits in the interdendritic areas, and with the increase in etching time, both the depth of the etching pits and the surface roughness increased. Moreover, the fatigue properties of the alloy were reduced after etching. The fatigue properties decreased with the increase in etching time. Etching was found to play a significant role on the high stress amplitude zone, while a smaller influence on the low stress amplitude zone. Compared with the results at 980 °C, the fatigue properties of the alloy at 760 °C were more affected by etching. The fatigue limits at 760 °C of the alloy after etching can be well predicted by the $$ \sqrt {\text{area}} $$ parameter model.

Effect of plasma treatment on the peel bond strength between maxillofacial silicones and resins.

The study aimed to investigate the effects of surface treatments, including plasma, on the peel bond strength between two maxillofacial silicones and two resins with and without thermocycling. Forty-eight experimental groups (n=10) were generated incorporating the two different resins (auto-polymerizing acrylic resin and light-curing urethane dimethacrylate resin [AR and LR, respectively]), two different silicones (M511 and Z004), aging (thermocycled/no thermocycling), and six different surface treatments, including polishing, grinding, polishing+argon plasma, polishing+oxygen plasma, grinding+argon plasma, and grinding+oxygen plasma. Surface topography of a specimen from each surface treatment group was examined by atomic force microscopy. After surface treatments, silicones were polymerized. The peel bond strength values of the control and thermocycled groups were determined. Atomic force microscopy showed that surface topographies of the ground specimens were irregular. Polished specimens showed higher peel bond strength than ground specimens. Plasma application appeared to have improved the bond strength between the resins and silicones.

Development of high-speed ion conductance microscopy.

Scanning ion conductance microscopy (SICM) can image the surface topography of specimens in ionic solutions without mechanical probe-sample contact. This unique capability is advantageous for imaging fragile biological samples but its highest possible imaging rate is far lower than the level desired in biological studies. Here, we present the development of high-speed SICM. The fast imaging capability is attained by a fast Z-scanner with active vibration control and pipette probes with enhanced ion conductance. By the former, the delay of probe Z-positioning is minimized to sub-10 µs, while its maximum stroke is secured at 6 μm. The enhanced ion conductance lowers a noise floor in ion current detection, increasing the detection bandwidth up to 100 kHz. Thus, temporal resolution 100-fold higher than that of conventional systems is achieved, together with spatial resolution around 20 nm.

Effect of Surface Topography Parameters on Friction and Wear of Random Rough Surface.

In order to explore the relationship between the surface topography parameters and friction properties of a rough contact interface under fluid dynamic pressure lubrication conditions, friction experiments were carried out. The three-dimensional surface topography of specimens was measured and characterized with a profile microscopy measuring system and scanning electron microscope. The friction coefficient showed a trend of decreasing first and then increasing with the increase in some surface topography parameters at lower pressure, such as the surface height arithmetic mean Sa, surface height distribution kurtosis Sku, surface volume average volume Vvv, and surface center area average void volume Vvc, which are the ISO 25178 international standard parameters. The effects of surface topographic parameters on friction were analyzed and the wear mechanism of the worn surface was presented. The wear characteristics of the samples were mainly characterized as strain fatigue, grinding, and scraping. The results provide a theoretical basis for the functional characterization of surface topography.

Effect of iron oxide debris on the reciprocating sliding wear of tool steels

The presence of wear debris in sliding contacts is often regarded as detrimental, since it can increase friction, induce abrasive wear, reduce actual lubricant film thickness and compromise lubrication systems. On the other hand, the presence of debris may be fundamental to the formation of a protective tribolayer, which can reduce friction and wear. This work investigates the effect of the presence of different iron oxides (F2O3 and Fe3O4) with different sizes on the unlubricated reciprocating sliding of tool steels. For that, sliding tests were carried out with and without the addition of iron oxides. The addition of Fe3O4 particles (larger and softer) resulted in friction (15%) and wear (95%) reduction. Two main factors seem to be responsible for friction and wear reduction when Fe3O4 particles were added into the contact. The first is the relative hardness of the debris in relation to the materials in contact. Since they are softer than the specimens and the counter bodies, they do not cause their severe abrasive wear, which is much more significant for the harder F2O3particles. The second is the relative size (RS) between the debris and the specimen surface topography. When RS is small, the debris get entrapped in the valleys of the specimen topography, thus not participating in the contact. On the other hand, for larger values of RS, the debris become active and therefore can participate in the formation of a protective tribolayer.

Cell Behavior on 3D Ti-6Al-4 V Scaffolds with Different Porosities.

Porous titanium (Ti) and its alloys fabricated by additive manufacturing (AM) techniques have attractive potential for dental and bone defect repair fields. Understanding the relationship between cells and the surface of the as-built three-dimensional (3D) scaffold interactions is not only necessary for tissue engineering but also promising for improving the fabrication process in the manufacture of artificial implants by AM technology. In this study, we have aimed to investigate the cell behavior including adhesion and proliferation of fibroblasts (L929) on Ti-6Al-4 V scaffolds fabricated by the electron beam melting method. The porosities of Ti-6Al-4 V scaffolds are 0% (compact), 60%, and 70%, respectively. Different cell behaviors have been observed from all of the specimens after 4 and 8 days of cell incubation. The present result indicates that, besides the surface roughness, the surface topography of specimens should also be taken into consideration to investigate the interaction between implants and cells. Therefore, this study would provide several possibilities for improving the osteointegration functions of the manufactured porous metallic implants in orthopedic and dental applications.

Measurement of steep edges and undercuts in confocal microscopy

Confocal microscopy is widely used to measure the surface topography of specimen with a precision in the micrometer range. The measurement uncertainty and quality of the acquired data of confocal microscopy depends on various effects, such as optical aberrations, vibrations of the measurement setup and variations in the surface reflectivity. In this article, the influence of steep edges and undercuts on measurement results is examined. Steep edges on the specimen's surface lead to a reduced detector signal which influences the measurement accuracy and undercuts cause surface regions, which cannot be captured in a measurement. The article describes a method to overcome the negative effects of steep edges and undercuts by capturing several measurements of the surface with different angles between the surface and the optical axis of the objective. An algorithm is introduced which stitches different angle measurements together without knowledge of the exact position and orientation of the rotation axis. Thus, the measurement uncertainty due to steep edges and undercuts can be avoided without expensive high-precision rotation stages and time consuming adjustment of the measurement setup.

SUS316NGの低サイクル疲労における表面性状変化とその機構

To investigate the cause of the change of arithmetic mean roughness Ra and arithmetic mean waviness Wa of austenitic stainless steel under low-cycle fatigue loading, precise observation focusing on slip bands and grain deformations was conducted on SUS316NG. During the fatigue tests, the specimen's surface topography was regularly measured using a laser microscope. The surface topographies obtained were analyzed by frequency analysis to separate the surface relief due to persistent slip bands from that due to crystal grain deformation. The height caused by persistent slip bands and that by crystal grain deformation were measured respectively. As a result, the both heights in initial stage of usage factor (UF) more developed compared with those in later stage of UF. The amount of increase in the heights with respect to UF increased with strain range. The trend of development of both heights was similar with the trend of Ra and Wa.

Comparison of platelet adhesion behavior on pure titanium surfaces modified by different techniques

To evaluate the platelet adhesion ability on pure titanium surfaces modified with different techniques. Pure titanium specimens were treated with 5 different surface modification techniques, including machine polish (MP), dual acid-etch (DAE), sand blast-large grit and acid-etch (SLA), micro-arc oxidation (MAO) and anodized titania nanotube (TNT). The surface topographies of specimens were observed by scanning electron microscopy (SEM). Chemical compositions, surface roughness and static water contact angle of specimens were detected by energy dispersive spectrometer (EDS), laser scanning confocal microscope (LSCM) and contact angle analyzer respectively. Platelets were cultured on specimen surfaces for 30 min. The amount and viability of adhered platelets adhered were evaluated. Platelet distribution and morphology were observed by LSCM and SEM. Surface topographies of the five groups of specimens differed significantly. MP, DAE, SLA and MAO surfaces showed micro-scale topographies, while TNT surfaces showed nano-scale topography with nanotubes at the diameter of (80.46 ± 0.35) nm. The surface roughness of MAO was the highest among the 5 groups. TNT surfaces demonstrated the lowest roughness as well as the lowest static water contact angle as 13.55° ± 0.96°. The amount of platelets adhered on TNT surface was the greatest as (300 729 ± 8 325) platelet/µl and the viability was the highest (A450 value 2.14 ± 0.05). Platelet adhered intensively on TNT surfaces, forming pseudopodia, extending and connecting with each other. Surface properties of pure titanium affect platelet adhesion ability. Nano-scale topography can greatly improve platelet adhesion. Increased surface roughness and hydrophilicity can improve platelet adhesion ability.

Effect of air-abrasion regimens and fine diamond bur grinding on flexural strength, Weibull modulus and phase transformation of zirconium dioxide.

This study evaluated the effect of air abrasion and polishing regimens on the flexural strength of yttrium stabilized polycrystalline tetragonal zirconia (Y-TZP). From Y-TZP blocks (InCeram 2000 YZ Cubes; Vita Zahnfabrik, Bad Säckingen, Germany) 120 bars (25 mm × 4 mm × 1.2 mm) were obtained according to ISO 6872:2008 and randomly divided into 4 groups: Group C: (control) without surface treatment (n = 30); Group APA: Air abrasion with aluminum oxide (44 µm) (n = 30); Group SC: Silica-coating (CoJet, 30 µm) (n = 30); Group FD: Fine diamond bur (n = 30). Subsequently, all specimens were subjected to 4-point bending test (in distilled water at 37 °C) in a universal testing machine (EMIC DL 1000; São José dos Pinhais, Paraná, Brazil); cross-head speed: 0.5 mm/min). The characteristic strength (σ0) of each specimen was obtained from the flexural strength test and evaluated using Weibull analysis. X-ray diffraction analysis was utilized to quantity the monoclinic phase. The surface topography of specimens was analyzed using 3D optical profilometer and scanning electron microscopy (SEM) after surface conditioning methods. The flexural strength data (σ4p) were statistically analyzed by 1-way ANOVA, Tukey test (α = 0.05) and Weibull (m = modulus, σ0 = characteristic strength) were calculated. The mean ± standard deviations (MPa) of the groups were as follows: C: 1196.2 ± 284.2a; APA: 1369.7 ± 272.3a; SC: 1207.1 ± 229.7a and FD: 874.4 ± 365.4b. The values (m) and (σ0) were as follows: C: 4.5 and 1308.12; APA: 5.9 and 1477.88; SC: 6.0 and 1300.28; and FD: 2.6 and 985.901, respectively. Air particle abrasion with neither silica nor alumina showed significant difference compared to the control group but grinding with fine diamond bur impaired the flexural strength of the zirconia tested.

Effects of clinical use and sterilization on surface topography and surface roughness of three commonly used types of orthodontic archwires.

To evaluate the changes in surface topography and roughness of stainless steel (SS), nickel-titanium and beta-titanium (β-Ti) archwires after clinical use and sterilization. Thirty wires each of SS, nitinol, and β-Ti (3M Unitek) were tested in as received, as received and autoclaved, and clinically retrieved then autoclaved conditions. A sterilization protocol of 134°C for 18 min was performed using an autoclave. Surface topography of specimens from each subgroup was examined using an environmental scanning electron microscope (ESEM model Quanta 200, The Netherlands) at ×100, ×1000, and ×2500 magnifications. Surface roughness was measured using arithmetic mean roughness (Ra) values obtained from optical profilometric scanning (Taylor Hobson, Leicester, UK). Data were analyzed by one-way analysis of variance and Tukey's post-hoc procedures. Scanning electron microscope images revealed an increase in surface irregularities in SS and nitinol wires after clinical use. There was a significant increase in Ra values of SS orthodontic wires after intra-oral exposure (P = 0.0002). Surface roughness of SS wires increased significantly after clinical use. Autoclave sterilization did not affect considerably on surface characteristics of any archwire.

G0301502 二段二重低サイクル疲労におけるSUS316NGの表面性状評価

To investigate the effects of change in loading amplitude on surface topography, two-step loaded low-cycle fatigue tests of SUS316NG austenitic stainless steel were conducted. During the tests, the specimen's surface topography was regularly measured using a laser scanning microscope. The surface topographies obtained were analyzed by frequency analysis to separate the surface relief due to persistent slip bands from that due to crystal grain deformation. The persistent-slip-bands-induced surface relief evolution and the grain-deformation-induced one were quantitatively evaluated by using arithmetic mean roughness R_a and arithmetic mean waviness W_a, respectively. As a result, the rates of increase in R_a and W_a changed obviously after changing loading amplitude. The results for R_a and W_a agree with the results of surface observation, the increases in the numbers of slip bands and deformed crystal grains changed after changing loading amplitude.

OS0913-454 低サイクル疲労損傷を受けたSU5316NGにおける表面粗さの分布特性

To statistically investigate the changes and the distributions in surface roughness, strain controlled low cycle fatigue tests of austenitic stainless steel were conducted under strain range Δε=8, 4%. During the tests, the specimen's surface topography was regularly measured using a laser scanning microscope. The surface topographies obtained were analyzed by frequency analysis to separate the surface relief due to persistent slip bands. The persistent-slip-bands-induced surface relief evolution was quantitatively evaluated by using arithmetic mean roughness R_a. As a result, R_a at Δε=8, 4% increased with the increase of UF (Usage Factor). The R_a data were plotted roughly linearly on a log-normal probability paper. It suggests that R_a likely follows a log-normal distribution. On the probability papers, the slope of R_a plots and the average value at Δε=8, 4% were clearly different. It shows that the distribution form of R_a varies between different Δε. The slopes of R_a plots at each UF were similar on the paper. It showed that the dispersion of R_a data didnot change even if UF increases.

Effect of surface topography on the dynamics of the abrasive particles during micro-abrasion

During abrasive wear, the wear mechanism has been shown to be associated with the movement of the active particles present at the wear interface: rolling, evidenced by indentations on the worn surface, and sliding, which produces scratching and/or ploughing. Particle dynamics can vary with tribological parameters such as different combinations of ball and specimen materials, applied load, slurry concentration, abrasive material, ball condition and equipment configuration (fixed or free-ball). In this article, the effect of surface topography of both the ball and the specimen on the dynamics of the abrasive particles and micro-abrasion wear is investigated for SiO2 abrasive particles. The effect of the ball surface topography was investigated using a fixed-ball rig, zirconia balls (Sa=0.06, 0.34, and 0.54µm) and stainless steel specimens (Sa=0.10µm). When the roughness of the ball increased, the wear mechanism changed from sliding to mixed and then to rolling and the micro abrasion coefficient k increased substantially, the difference between the smoothest and the roughest ball being around 510%. The effect of the specimen surface topography was investigated using a free-ball rig, AISI 52100 steel balls (Sa=0.82µm) and tool steel specimens (Sq=0.025µm and 0.414µm). The influence of the directionality of the specimen surface finish was also analyzed by conducting tests parallel and perpendicular to the grinding marks using three slurry concentrations. The effect of the topography of the specimens on wear coefficients and mechanisms was much less pronounced than that found for the ball topography. For the highest slurry concentration (20wt%), k increased for the rougher specimens (around 23%) and a slight change in mechanism occurred from mixed (sliding in the center and rolling at borders of craters), to sliding. This effect was less significant for lower concentrations. The influence of surface directionality on abrasive wear was negligible.

Study on the Fractal Behavior and Fractal Characterization of Guide Way Joint Surface

The characterization of guide way joint surface micro-topography is very important for the study of real guide way joint surface. Based on fractal theory, fractal characteristics of rough surface are investigated. The 3D surface topography of specimen which is closed to machine tool guide way both in material and processing condition is obtained by atomic force microscope (AFM). The structure function method is employed to gain fractal dimension and the analysis of fractal characteristics. The results show that meet the processing conditions, the guide way joint surface in the region which can scale show good linear relationship and has obvious fractal.