Profilometric Analysis Research Articles

Comparison of surface abrasion produced on the enamel surface by a standard dentifrice using three different toothbrush bristle designs: A profilometric in vitro study.

Aim:The aim was to assess, in vitro, the effect on surface abrasivity of enamel surface caused by three different types (flat trim, zig-zag, bi-level) of toothbrush bristle design.Materials and Methods:Twenty-four freshly extracted, sound, human incisor teeth were collected for this study. The enamel slab was prepared, which were mounted, on separate acrylic bases followed by subjected to profilometric analysis. The surface roughness was measured using the profilometer. The specimen were divided into three groups, each group containing eight mounted specimens, wherein, Group 1 specimens were brushed with flat trim toothbrush; Group 2 brushed with zig-zag and Group 3 with bi-level bristle design. A commercially available dentifrice was used throughout the study. A single specimen was brushed for 2 times daily for 2 min period for 1 week using a customized brushing apparatus. The pre- and post-roughness value change were analyzed and recorded.Statistical test:Kruskal–Wallis test and Mann–Whitney U-test.Result:The results showed that surface abrasion was produced on each specimen, in all the three groups, which were subjected to brushing cycle. However, the bi-level bristle design (350% increase in roughness, P = 0.021) and zig-zag bristle design (160% increase in roughness, P = 0.050) showed significantly higher surface abrasion when compared with flat trim bristle design toothbrush.Conclusion:Flat trim toothbrush bristle produces least surface abrasion and is relatively safe for use.

Evaluation of 3C-SiC/Si residual stress and curvatures along different wafer direction

During the heteroepitaxial growth of a thin film on a thick substrate, important stresses arise in the grown material and may influence the physical properties of the film. The residual stresses result in a bending of the substrate/film system. In this work the evaluation of the wafer curvature and the residual stress along different crystallographic directions of the wafer was proposed. Performed by an interferometric optical profilometer, optical microscope and X-ray diffraction analysis, the curvature of the wafer along the [110] and [1−10] wafer directions was observed for hetero-epitaxial Cubic Silicon Carbide (3C-SiC) on Si (001) films. As a consequence of the stress generated during hetero-epitaxy, due to the difference in thermal expansion coefficient and lattice mismatch between the two materials, an asymmetric wafer curvature was observed.

Graded-size microlens array by the pyro-electrohydrodynamic continuous printing method

In the present work, the pyro-electrohydrodynamic technique was used for the realization of tunable-size microlens arrays. Poly(methyl methacrylate) dissolved in different solvent mixtures was used as the polymeric material for the realization of the microstructures. By controlling the experimental parameters and in particular, the volume of the drop reservoir, graded-size square arrays of tens of microlenses with focal length in the range 1.5-3 mm were produced. Moreover, the optical quality and geometrical features were investigated by profilometric and interferometric analysis.

Low‐temperature degradation of a Y‐TZP ceramic after surface treatments

The purpose of this study was to evaluate the influence of zirconia surface treatments on low-temperature degradation (LTD). Disc-shaped specimens were subjected to one of four surface treatments, denoted as C (control-no surface treatment), Si (air abrasion with 30 µm silica-modified alumina particles), Al (air abrasion with 30 µm alumina particles), and Gr (grinding with 120 grit diamond discs). Half of the samples were submitted to autoclave treatment for 12 h (127°C, 1.5 bar). Samples were characterized by x-ray diffraction and profilometer analysis and were subjected to biaxial flexural strength test. All of the groups exhibited an increase in the amount of monoclinic phase (m-phase) after LTD. The t→m transformation was remarkable for the specimens from the C group, which also exhibited a significant increase in strength. The Gr group also exhibited an increase in strength but lower initial roughness, which probably suppressed LTD on the zirconia surface. The specimens subjected to air abrasion exhibited higher initial amounts of m-phase and a small increase in m-phase after LTD; the strength was not affected in these groups. The effects of LTD were different with each surface treatment applied. Apparently, LTD may be suppressed by smoother surfaces or the presence of an initial amount of m-phase on zirconia surface.

Friction and Wear Mechanisms of Phenolic-Based Materials on High Speed Tribometer

This work takes place in the understanding of the friction and wear mechanisms occurring in reinforced phenolic materials, widely used in organic braking pads. As the matrix is filled with a large variety of particles, the phenomena in the contact zone are complex and multiphysic. In a first approach the reinforcement is restricted to spherical steel particles with diameters in the range of the fibbers size. The influence of the sliding speed, the mean normal pressure and the contact temperature are examined and the benefits of using this kind of particle is as well discussed. The tribological tests are performed on a newly developed High Speed Tribometer designed to reproduce braking conditions. The results show that temperature is the most influential parameter, leading to a decrease of the friction coefficient. They further indicate that reinforcement pushes the loss of efficiency to a higher temperature. Optical observations and profilometer analysis show that the wear mechanisms are clearly dependent on friction conditions. These results improve our knowledge of wear debris formation and conditions leading to particle debonding in phenolic matrix material.

On the optical microscopic method for the determination of ball-on-flat surface linearly reciprocating sliding wear volume

A simple approach for wear volume calculation by optical microscopic technique is proposed for ball-on-flat surface linearly reciprocating sliding wear. The depths at different positions of the worn out section are measured by focusing and defocusing from the flat surface of the sample. Length and width are measured by the movement of focused point along the surface. Image-J software is used to obtain best focused image by maximization of intensity. Measured depths are used to calculate wear volume using a modified geometric equation for the worn out section of the sample consisting of truncated cylinder with central flat bottom and double truncated spheres at two ends. The wear volume measurement is carried out for number of steel samples at different load values at a fixed frequency and it compares well with that determined by laser profilometric analysis.

A novel approach to wear testing in hot stamping of high strength boron steel sheets

Hot stamping of high strength steel sheets was developed in the automotive industry for the production of components characterized by a high strength-to-weight ratio and an increased resistance to impact. In order to avoid scaling and decarburization, the steel blanks are usually coated with an Al–Si coating that has proved a relevant influence also on their tribological behaviour during the forming stages. However, the knowledge of the influence that this coating may have on the dies wear mechanisms is still inadequate.The paper proposes a novel approach to wear testing, based on a pin-on-disk testing configuration, capable to reproduce in a laboratory environment the conditions arising at the interface between the dies and the blank, by reproducing the sliding velocities at the interface and the cyclic thermal and mechanical stresses on the die material. Investigations were carried out on a hot working tool steel sliding against high strength steel blanks coated with the Al–Si coating under dry reciprocating sliding conditions. Scanning electron microscopy and 3D profilometer analysis were utilized to evaluate the wear mechanisms.The presented results show that the proposed procedure can properly simulate the thermal and mechanical cycles to which the forming dies are subjected during the hot stamping process, allowing to control and vary a number of parameters characterizing the industrial process. The presence of both adhesive and abrasive wear mechanisms is highlighted and a possible explanation of their appearance is given.

Magnetic and structural investigation of growth induced magnetic anisotropies in Fe50Co50thin films

In this paper, we investigate the magnetic properties of Fe50Co50 polycrystalline thin films, grown by dc-magnetron sputtering, with thickness (t) ranging from 2.5 nm up to 100 nm. We focused on the magnetic properties of the samples to highlight the eects of possible intrinsic stress that may develop during growth, and their dependence on film thickness. Indeed, during film deposition, due to the growth technique and growth conditions, a metallic film may display an intrinsic compressive or tensile stress. In our case, due to the Fe50Co50 magnetolastic properties, this stress may in its turn promote the development of magnetic anisotropies. Samples magnetic properties were monitored with a SQUID magnetometer and a magneto-optic Kerr eect apparatus, using both an in-plane and an out-of-plane magnetic field. Magnetoresistance measurements were collected, as well, to further investigate the magnetic behavior of the samples. Indications about the presence of intrinsic stress were obtained accessing samples curvature with an optical profilometer. For t ≤ 20 nm, the shape of the in-plane magnetization loops is squared and coercivity increases with t, possibly due to fact that, for small t values, the grain size grows with t. The magnetoresistive response is anisotropic in character. For t > 20 nm, coercivity smoothly decreases, the approach to saturation gets slower and the shape of the whole loop gets less and less squared. The magnetoresistive eect becomes almost isotropic and its intensity increases of about one order of magnitude. These results suggest that the magnetization reorientation process changes for t > 20 nm, and are in agreement with the progressive development of an out-of-plane easy axis. This hypothesis is substantiated by profilometric analysis that reveals the presence of an in-plane compressive stress.

Profilometric analysis of two composite resins′ surface repolished after tooth brush abrasion with three polishing systems

Aim:To evaluate the effect of three polishing protocols that could be implemented at recall on the surface roughness of two direct esthetic restorative materials.Materials and Methods:Specimens (n = 40) measuring 8 mm (length) × 5 mm (width) × 4 mm (height) were fabricated in an acrylic mold using two light-cured resin-based materials (microfilled composite and microhybrid composite). After photopolymerization, all specimens were finished and polished with one of three polishing protocols (Enhance, One Gloss, and Sof-Lex polishing systems). The average surface roughness of each treated specimen was determined using 3D optical profilometer. Next all specimens were brushed 60,000 times with nylon bristles at 7200 rpm using crosshead brushing device with equal parts of toothpaste and water used as abrasive medium. The surface roughness of each specimen was measured after brushing followed by repolishing with one of three polishing protocols, and then, the final surface roughness values were determined.Results:The data were analyzed using one-way and two-factor analysis of variance (ANOVA) and Tukey's honestly significant difference (HSD). Significant difference (P < 0.05) in surface roughness was observed. Simulated brushing following initial polishing procedure significantly roughened the surface of restorative material (P < 0.05).Conclusion:Polishing protocols can be used to restore a smooth surface on esthetic restorative materials following simulated tooth brushing.

Profilometric and SEM analyses of composite surfaces after excess cement removal

Composite cements are widely used in dentistry, due to their positive characteristics (bond strength, color, low solubility etc.). However, removal of the cement presents one of the drawbacks of their use, since incomplete removal might cause bacterial adhesion, gingival irritation and subsequent inflammation. The aim of this study was to investigate surface characteristics of the composite cements after different ways of excess removal, by means of profilometric and SEM analysis. Thirty leucite reinforced ceramic specimens were divided into three groups, based on the manner of excess cement removal: Group 1 (polished): excess was fully polymerized for 40 s, then removed; Group 2 (cleaned): excess was removed with a cotton roll, after which cement was fully polymerized for 40 s; Group 3 (pre-polymerized): excess was light cured for 5 s, after which cement excess was broken with an instrument and then fully polymerized for 40 s. Surface roughness was measured using a surface profilometer. Subsequently, specimens were inspected by a scanning electron microscope. The data were statistically analyzed. The examination of variants of average values proved the statistically significant difference in the height of average values per group, p&lt;0.0001; the statistically significantly highest values were for the pre-polymerized group, whereas the statistically significantly lowest values were for the polished group. Results of this study show that utmost attention has to be paid to the excess removal procedure, since surface roughness parameters directly depend on the choice of the applied technique.

Comparative evaluation of roughness of titanium surfaces treated by different hygiene instruments

PurposeThe use of appropriate instruments to clean surfaces with minimal change, is critical for the successful maintenance of a dental implant. However, there is no consensus about the type and methodology for such instruments. The aim of this study was to characterize changes in the roughness of titanium surfaces treated by various scaling instruments.MethodsThirty-seven identical disks (5 mm in diameter) were investigated in this study. The specimens were divided into eight groups according to the types of instrumentation and the angle of application. Ultrasonic scaling systems were applied on a titanium disk to simulate standard clinical conditions. The equipment included a piezoelectric ultrasonic scaler with a newly developed metallic tip (NS group), a piezoelectric ultrasonic scaler with a conventional tip (CS group), a piezoelectric root planer ultrasonic scaler with a conventional tip (PR group), and a plastic hand curette (PH group). In addition, the sites treated using piezoelectric ultrasonic scaler systems were divided two sub-groups: 15 and 45 degrees. The treated titanium surfaces were observed by scanning electron microscopy (SEM), and the average surface roughness (Ra) and mean roughness profile depth (Rz) were measured with a profilometer.ResultsSEM no significant changes in the titanium surfaces in the NS group, regardless of the angle of application. The PH group also showed no marked changes to the titanium surface, although some smoothening was observed. All CS and PR sites lost their original texture and showed irregular surfaces in SEM analysis. The profilometer analysis demonstrated that the roughness values (Ra and Rz) of the titanium surfaces increased in all, except the PH and NS groups, which showed roughness decreases relative to the untreated control group. The Ra value differed significantly between the NS and PR groups (P<0.05).ConclusionsThe results of this study indicated that changes in or damage to titanium surfaces might be more affected by the hardness of the scaler tip than by the application method. Within the limitations of this study, the newly developed metallic scaler tip might be especially suitable for peri-implant surface decontamination, due to its limited effects on the titanium surface.

Effect of simulator design on in vitro profilometric assessment of toothpaste abrasivity

National and international standards detail in vitro methodologies for assessing toothpaste abrasivity using human enamel and dentine coupled with profilometric or radioisotope analysis. This profilometry-based study investigates the influence of brushing simulator design and choice of standard abrasive on enamel/dentine wear. Four simulators were evaluated including the flat-bed and V8 Grabenstetter designs described in the present BS EN ISO 11609: 1998 standard, together with the two abrasives prescribed therein. Vertical reciprocating-action and rotary-action simulators were also assessed. Mean abrasion depths for enamel and dentine specimen groups using the rotary-action simulator with either abrasive were ca. 0.9μm and 4–5μm respectively, significantly higher vs. comparators (p=0.0001; CV∼0.2). Mean abrasion depths determined using the flat-bed and V8 simulators were ≤0.1μm (CV, 0.2–0.8) for enamel and ≤0.7μm (CV, 0.2–0.6) for dentine. The vertical reciprocating-action simulator elicited intermediate levels of wear, but high design-driven variance (CV, 0.6–0.7). Mean enamel abrasion depths were independent of abrasive (p≥0.534), however, mean dentine abrasion depths were significantly different for the vertical reciprocating and rotary-action simulators (p=0.0026 and 0.0014 respectively). This study demonstrates the importance of simulator design in the assessment of dentifrice abrasivity, which is key to delivering the desired sensitivity and discriminatory power. Various limitations in design of the simulators studied highlight opportunities for improvements in simulator design.

Modelling micro geometrical profiles in fused deposition process

Fused deposition modelling is an established additive manufacturing technique for creating functional prototypes from three-dimensional computer-aided design models. Despite of the potential advantages of this technology, surface roughness is a substantial problem and some attempts have been made to predict the average roughness Ra. As well known, the surface quality characterization of a part is not limited to Ra but involves many other roughness parameters. The knowledge in advance of these parameters is a critical point especially in the product design stage both for rapid prototyping purpose and finished part manufacturing. In this work, a novel approach aimed to the geometrical description of roughness profile is reported. By means of an analytic formulation it is possible to calculate custom set of roughness parameters. An experimental analysis, based on design of experiments technique, is carried out to investigate the effects of several factors on shape profile. The achieved results permit to define the domain in which the presented model depends only on two parameters. A profilometric analysis has been performed on specimens properly designed to validate the method. Statistical tests show a good accordance with predicted values for the made assumptions and the calculated roughness parameters.

Surface characterization of feldspathic ceramic using ATR FT-IR and ellipsometry after various silanization protocols

Objectives This study characterized the feldspathic ceramic surfaces after various silanization protocols. Methods Ceramic bars (2 mm × 4 mm × 10 mm) ( N = 18) of feldpathic ceramic (VM7, VITA Zahnfabrik) were manufactured and finished. Before silane application, the specimens were ultrasonically cleaned in distilled water for 10 min. The ceramic specimens were randomly divided into nine groups ( N = 2 per group) and were treated with different silane protocols. MPS silane (ESPE-Sil, 3M ESPE) was applied to all specimens and left to react at 20 °C for 2 min (G20). After drying, the specimens were subjected to heat treatment in an oven at 38 °C (G38), 79 °C (G79) or 100 °C (G100) for 1 min. Half of the specimens of each group were rinsed with water at 80 °C for 15 s (G20B, G38B, G79B, G100B). The control group (GC) received no silane. Attenuated total reflection infrared Fourier transform analysis (ATR FT-IR) was performed using a spectrometer. Thickness of silane layer was measured using a spectroscopic ellipsometer working in the λ = 632.8 nm (He–Ne laser) at 70° incidence angle. Surface roughness was evaluated using an optical profilometer. Specimens were further analyzed under the Scanning Electron Microscopy (SEM) to observe the topographic patterns. Results ATR FT-IR analysis showed changes in Si–O peaks with enlarged bands around 940 cm −1. Ellipsometry measurements showed that all post-heat treatment actions reduced the silane film thickness (30.8–33.5 nm) compared to G20 (40 nm). The groups submitted to rinsing in hot water (B groups) showed thinner silane films (9.8–14.4 nm) than those of their corresponding groups (without washing) (30.8–40 nm). Profilometer analysis showed that heat treatments (Ra ≈ 0.10–0.19 μm; Rq ≈ 0.15–0.26 μm) provided a smoother surface than the control group (Ra ≈ 0.48 μm; Rq ≈ 0.65 μm). Similar patterns were also observed in SEM images. Significance Heat treatment after MPS silane application improved the silane layer network. Rinsing with boiling water eliminated the outmost unreacted regions of the silane yielding to thinner film thicknesses.

Prevention of toothbrushing abrasion of acid-softened enamel by CO 2 laser irradiation

Objective The aim of the present study was to evaluate the effect of CO 2 laser irradiation (10.6 μm) at 0.3 J/cm 2 (0.5 μs; 226 Hz) on the resistance of softened enamel to toothbrushing abrasion, in vitro. Methods Sixty human enamel samples were obtained, polished with silicon carbide papers and randomly divided into five groups ( n = 12), receiving 5 different surface treatments: laser irradiation (L), fluoride (AmF/NaF gel) application (F), laser prior to fluoride (LF), fluoride prior to laser (FL), non-treated control (C). After surface treatment they were submitted to a 25-day erosive-abrasive cycle in 100 ml sprite light (90 s) and brushed twice daily with an electric toothbrush. Between the demineralization periods samples were immersed in supersaturated mineral solution. At the end of the experiments enamel surface loss was determined using a contact profilometer and morphological analysis was performed using scanning electron microscopy (SEM). For SEM analysis of demineralization pattern, cross-sectional cuts of cycled samples were prepared. The data were statistically analysed by one-way ANOVA model with subsequent pairwise comparison of treatments. Results Abrasive surface loss was significantly lower in all laser groups compared to both control and fluoride groups ( p < 0.0001 in all cases). Amongst the laser groups no significant difference was observed. Softened enamel layer underneath lesions was less pronounced in laser-irradiated samples. Conclusion Irradiation of dental enamel with a CO 2 laser at 0.3 J/cm 2 (5 μs, 226 Hz) either alone or in combination with amine fluoride gel significantly decreases toothbrushing abrasion of softened-enamel, in vitro.

Corrosion and tribocorrosion behaviour of thermally sprayed ceramic coatings on steel

This research aims at investigating the corrosion and tribocorrosion behaviour of thermally sprayed ceramic coatings deposited on steel specimens and exposed to a 3.5% NaCl solution. The coatings have been prepared by plasma spraying Cr2O3 and Al2O3/13% TiO2 powders on a Ni/20% Cr bond coating. Combined wear–corrosion conditions have been achieved by sliding an alumina antagonist on the lateral surface of coated steel cylinders, during their exposure to the aggressive solution.Polarization resistance values monitored during 3days exposures and polarization curves recorded at the end of the immersion period show that both coatings only partially protect steel substrate from corrosion. Sliding conditions (under 2N load and 20rpm or 10N and 100rpm) induce a limited increase of the substrate corrosion rates, likely as a consequence of an increase in the defect population of the ceramic coatings.On Cr2O3-coated specimens, tribocorrosion is more severe at 10N and 100rpm, while on Al2O3/13% TiO2-coated specimens, a stronger corrosion attack is achieved at 2N and 20rpm. Profilometer analysis and wear track observations by optical and scanning electron microscopes evidence that on both coatings abrasion of the surface asperities produce both a surface polishing effect and, at high loads, the formation of a tribofilm, more continuous on Al2O3/13% TiO2. On this coating the tribofilm reduces the amount of surface defects and limits the corrosion attack to a certain extent.

An In Vivo Study of the Effect of a 38 Percent Hydrogen Peroxide In-office Whitening Agent on Enamel

In an in vivo study, the authors tested the hypothesis that no difference in enamel surface roughness is detectable either during or after bleaching with a high-concentration in-office whitening agent. The authors performed profilometric and scanning electron microscopic (SEM) analyses of epoxy resin replicas of the upper right incisors of 20 participants at baseline (control) and after each bleaching treatment with a 38 percent hydrogen peroxide whitening agent, applied four times, at one-week intervals. The authors used analysis of variance for repeated measures to analyze the data statistically. The profilometric analysis of the enamel surface replicas after the in vivo bleaching protocol showed no significant difference in surface roughness parameters (P > .05) compared with those at baseline, irrespective of the time interval. Results of the correlated SEM analysis showed no relevant alteration on the enamel surface. Results of this in vivo study support the tested hypothesis that the application of a 38 percent hydrogen peroxide in-office whitening agent does not alter enamel surface roughness, even after multiple applications. The use of a 38 percent hydrogen peroxide in-office whitening agent induced no roughness alterations of the enamel surface, even after prolonged and repeated applications.

Characterization of profilograms of piecewise-continuous diffraction microrelief

Questions of the profilometric analysis of the piecewise-continuous microrelief of high-efficiency diffraction elements have been virtually ignored in the literature, even though the market for diffraction optics has substantially increased in recent years, and high-efficiency diffraction elements have gone from the realm of the exotic to ordinary practice of optical instrumentation. In this paper, the authors consider several techniques for evaluating microrelief that make it possible to compute the “approximated depth,” almost regardless of the type of profilometer being used. The proposed techniques are based on a polynomial approximation of the diffraction-zone profile with minimization of the influence of the unreliable data close to its boundaries.

Comparison of parametric and profilometric surface analysis methods on machined surfaces

In this work, a comparison of three different methods for analysing topographies and roughness on machined metal surfaces is presented. To obtain comparable results, the measurements were done on one and the same set of samples. For this purpose, an atomic force microscope (AFM), a confocal white light microscope, and a scattering light system were used to analyse the topography of samples of the same material, but with the topographies occurring step by step from the grinding process to the polishing process. Based on the results of the investigations with the parametric system (scattering light sensor) and the profilometric systems (AFM, confocal white light microscope), we established a correlation between the roughness parameters and the scattering light parameter. It is shown that the different methods lead to different roughness parameters of the same surface.

Effect of sliding speed on tribological characteristics of different surface textures on AISI O1 steel irradiated by Nd:YAG pulsed laser

The tribological characteristics of surface microtexture [inline (IN) pattern and staggered (ST) pattern] irradiated by Nd:YAG laser on AISI O1 steel with various sliding speed were investigated. Using 'pin-on-disc' wear test, the effect of sliding speed on the frictional coefficient; wear loss and surface morphology had been studied by optical microscopy, scanning electron microscopy, surface profilometer and energy dispersive X-ray analysis. Results showed that in comparison with non-patterned (NP) smooth steel surface the steel surface with laser microexturing significantly reduced friction and wear. Moreover, for the two laser textured patterns, ST pattern tribocouples showed the best tribological behaviour, which was attributed to the hydrodynamic pressure of lubrication film formatted by its specific microtexture pattern.