Differences In Roughness Values Research Articles

Evaluation of enamel surface integrity after orthodontic bracket debonding: comparison of three different system.

This study aimed to evaluate enamel surface integrity and time consumed during residual cement removal after bracket debonding using different adhesive removal burs with and without a dental loupe. Sixty human-extracted premolars were collected, cleaned, mounted, and prepared for orthodontic bracket bonding. Teeth were randomly divided into three main groups (n = 20) based on the adhesive removal method: tungsten carbide system (TC), sof-lex discs system (SD), and diamond system (DB) groups. Then, each group was subdivided into two subgroups (naked eye and magnifying loupe subgroups). The brackets were bonded and then debonded after 24h, and the Adhesive Remnant Index (ARI) was assessed. The adhesive remnants were removed by different systems, and the final polishing was performed by Silicone OneGloss. The enamel surface roughness was evaluated before bracketing (T0), after residual cement removal (T1), and finally after polishing (T2) using surface Mitutoyo SJ-210 profilometry and Scanning Electron Microscopy (SEM) to determine the Enamel Damage Index (EDI) score. The time consumed for adhesive removal was recorded in seconds. The Kruskal Wallis test showed a statistically significant difference in roughness values at T1 compared to T2 between subgroups (p < 0.001). When comparing EDI at T1 and T2, the Kruskal-Wallis H-test showed statistically significant differences in all subgroups. The pairwise comparisons revealed that EDI scores showed a statistically significant difference at T1 and T2 between DB vs. TC and SD (p = 0.015) but not between TC vs. SD (p = 1.000), indicating the highest roughness value observed in the DB group. The time for cement removal was significantly shorter in the magnifying loupe group than in the naked eye group and was shortest with the TC group, whereas the time was the longest with the DB group (p < 0.05). All three systems were clinically satisfactory for residual orthodontic adhesive removal. However, TC system produced the lowest enamel roughness, while the DB system created the greatest. The polishing step created smoother surfaces regardless of the systems used for resin removal.

Surface Characteristics and Adhesion of Veneering Composite Resin to PAEK-Based Substructure Restorative Materials.

To evaluate and compare the shear bond strength (SBS) of composite veneering material to polyetherketoneketone (PEKK), polyetheretherketone (PEEK), zirconia (YZ), and nickel-chromium alloy (NiCr) substructure restorative materials. Forty samples (12 × 2 mm) were prepared from four materials: PEKK, PEEK, zirconia, and NiCr alloy (n = 10). The Vickers hardness was evaluated before preparing the surface for bonding by shot-blasting using 110 μm Al2 O3 particles. The surface roughness (Ra) of each sample was determined using a noncontact optical profilometer. The veneering resin was bonded onto each sample following primer application. The prepared samples were then subjected to an SBS test using a universal testing machine at 0.5 mm/min crosshead speed. Failure modes and surface topography following debonding were assessed. The data were statistically analyzed using ANOVA and Tukey'spost-hoccomparison test (p < 0.05). RESULTS: The highest and lowest mean surface roughness was observed in PEEK (3.45 ±0.13 μm) and NiCr (1.87 ±0.07 μm) materials, respectively. A significant difference in roughness values was observed between the materials except for NiCr and YZ (p = 0.547). Concerning SBS, PEEK and NiCr exhibited the highest (16.23 ±0.96 MPa) and lowest (10.1 ±0.63 MPa) values. The mean difference in SBS indicated a statistically significant difference between the material groups (p < 0.01). PEKK materials demonstrated significantly lower SBS than PEEK and significantly higher SBS values than conventional zirconia and alloy materials. A positive and significant correlation between mean roughness and SBS was observed, but the causality could be either intrinsic to the material or the roughness.

Antibiofilm and Protein-Repellent Polymethylmethacrylate Denture Base Acrylic Resin for Treatment of Denture Stomatitis.

Candida albicans (C. albicans) biofilm is a common etiological factor in denture stomatitis. The purpose of this study was to investigate the effects of incorporating 2-methacryloyloxyethyl phosphorylcholine (MPC) as a protein repellent into a new high-impact denture acrylic (HIPA) resin on the surface roughness, solution pH, and C. albicans biofilm adhesion to the denture base. The new acrylic denture resin base was formulated by mixing MPC into HIPA resin at mass fractions of 1.5%, 3%, and 4.5%. Surface roughness was measured using a Mitutoyo surface roughness tester. C. albicans biofilm growth and viability were assessed via colony forming unit counts. The pH of the biofilm growth medium was measured using a digital pH meter. Adding MPC to the HIPA resin at percentages of 1.5% and 3% increased the roughness values significantly (p < 0.05), while adding 4.5% MPC resulted in no difference in roughness values to that of the control group (p > 0.05). All experimental groups demonstrated neutral pH values (pH ≅ 7) and were not significantly different from each other (p > 0.05). Incorporating 2-methacryloyloxyethyl phosphorylcholine at 4.5% resulted in a significant (≅1 log) colony-forming unit reduction compared with the control group with 0% MPC (p < 0.05). A fungal-retarding denture acrylic resin was developed through the incorporation of MPC for its protein-repelling properties. This newly developed denture acrylic material has the potential to prevent oral microbial infections, such as denture stomatitis.

The crack surface morphology investigation of S355J2 steel after bending-torsion fatigue

The paper describes the analysis of crack surface morphology of S355J2 steel specimens after bending-torsion fatigue. These experimental investigations of the surface topography were carried out using the focus variation microscope, an optical 3D measurement device. Selected results of measured fracture surfaces for S355J2 steel were analysed according to the surface texture ISO 25178 standard. Differences in roughness values for different loadings were demonstrated. For profile Rx and areal Sx parameters, characteristic relationships of fracture zones have been demonstrated. It has been shown that roughness profile Ra for the rupture area is higher than for the propagation area, as well as increases after both the LCF and HCF tests and increases with the torsional loading level. However, Sa in the propagation area increases and the rupture area decreases.

Effect of violet led associated with low-concentration hydrogen peroxide on enamel surface roughness

Aim: The present study aimed to assess in vitro the effect ofviolet LED in tooth bleaching techniques associated or not withlow-concentration hydrogen peroxide gel on enamel surfaceroughness. Methods: Fifty-two enamel fragments of bovineteeth were flattened and polished (4x4x3 mm) and dividedinto four groups according to bleaching treatment: VL- VioletLED; HP- 7.5% hydrogen peroxide; HP+VL- 7.5% hydrogenperoxide + violet LED; C- No bleaching (control). Before thetreatments, all specimens were immersed in 20 mL of blacktea for six days, changing solutions every 24 h to simulatethe staining of specimens. Forty fragments were used toanalyze surface roughness (n=10) and 12 fragments wereused for the morphological analysis (SEM) (n=3). Results:The data were submitted to one-way ANOVA and a post-hocTukey test. The lower roughness values was observed for thegroup that did not receive bleaching treatment (C), differingsignificantly only from the group bleached with 7.5% hydrogenperoxide + violet LED (HP+VL) (p=0.0077). The remaininggroups did not show significant differences in roughnessvalues (p&gt;0.05). The scanning electron microscopy analysisshowed irregularities on the enamel surface regardless ofthe treatment received. Conclusion: The results showedthat bleaching treatments with violet LED associated withlow-concentration hydrogen peroxide gels (7.5%) increasethe surface roughness of tooth enamel.

Does Modification of Amalgomer with Propolis Alter Its Physicomechanical Properties? An In Vitro Study.

Objective To assess if incorporating ethanolic extract of propolis into ceramic-reinforced glass ionomer (Amalgomer CR) might have an influence on its physicomechanical properties. Materials and Methods Three groups were assessed; group I: Amalgomer CR (control) and two experimental groups (II and III) of propolis added to the liquid of Amalgomer CR with 25 and 50 v/v %, respectively. Evaluation parameters were color stability, compressive strength, microhardness, and surface roughness. Representative specimens of each group were analyzed by Fourier-transform infrared spectroscopy, energy-dispersive X-ray, X-ray diffraction, and scanning electron microscopy. Analysis of variance (ANOVA) was used to compare the results, followed by a Tukey post hoc test (p < 0.05). Results Nonsignificant color change for both groups of modified Amalgomer CR. Meanwhile, the two experimental groups exhibited a significant increase in both compressive strength and microhardness. Simultaneously, there was a significant difference in roughness values among groups with the lowest roughness values exhibited by the 50 v/v % propolis concentration. Conclusions Modification of Amalgomer CR with 50 v/v % propolis may increase its mechanical properties without compromising its esthetic. Clinical Significance. Modification of Amalgomer CR by 50 v/v % propolis is supposed to be a hopeful restorative material with favorable characteristics.

The role of spatial frequency analysis in correlating atomic force microscopy and optical profilometry with self-etch adhesive enamel bond fatigue durability.

The purpose of this study was to: (a) evaluate the role of enamel surface roughness on bond fatigue durability and (b) evaluate statistical differences in roughness values based on measurement technique, including the use of spatial filtering for optical profilometry (OP). OptiBond XTR (Kerr Corp), Prime & Bond elect (DENTSPLY Caulk), Scotchbond Universal (3 M Oral Care), and XTR pre-etched with Ultra-Etch phosphoric acid (35%) (Ultradent) self-etch adhesives were used to treat enamel. A flat ground enamel surface was included as a control. Atomic force microscopy (AFM) and OP were used to measure the surface topography of each enamel surface following the application of adhesives. AFM, OP, and filtered OP (FOP) roughness values, where FOP was designed to only include the lateral spatial resolution consistent with AFM roughness values, were collected. Spatial resolution filtering with OriginPro was used to compare line scans from the two imaging techniques and generate the FOP group. These micro- versus nanoscale lateral roughness values were correlated with shear bond and shear fatigue strengths of the adhesives bonded to enamel. Roughness values showed differences based on measurement technique and strong correlations with bond and fatigue strength. The filtered OP group demonstrated the importance of careful usage and reporting of atomic force microscopy and OP metrics in adhesive dentistry. Best practices for surface roughness analysis were also discussed.

Adhesion of Streptococcus mutans and Streptococcus sanguinis on Er:YAG Laser-Irradiated Dental Enamel: Effect of Surface Roughness.

Objective: To determine surface roughness caused by Er:YAG laser irradiation and its effect on the increase in bacterial adhesion. Background: Er:YAG laser was proposed as a strategic device to reduce caries by its ability to generate chemical and structural changes in tooth enamel; in turn, it produces undesirable effects on the tooth surface that could increase its roughness and allow a greater accumulation of microorganisms. Methods: Eighty-four samples of human enamel were divided into seven groups (n = 12): G1_control (no laser irradiation); G2_100/H2O, G3_200/H2O, and G4_300/H2O were irradiated with Er:YAG laser (12.7, 25.5, and 38.2 J/cm2, respectively) under water irrigation. In addition, G5_100, G6_200, and G7_300 were irradiated with the energy densities described above and no water irrigation. Surface roughness measurements were recorded before and after treatment using a profilometer. Afterward, three samples per group were incubated in a microorganism suspension for the tetrazolium salt (XTT) assay. Biofilm morphology was observed using scanning electron microscopy and confocal laser scanning microscope. One-way analysis of variance and t-tests were performed for statistical analysis (p < 0.05). Results: There were no statistically significant differences in roughness values in the G5_100 group before and after treatment, but there were statistically significant differences observed in the other groups evaluated (p < 0.05). No significant differences in adhesion of both strains were detected in irradiated groups compared with G1_control. Conclusions: The increase in roughness on dental enamel surfaces was proportional to the irradiation conditions. However, the increase in surface roughness caused by Er:YAG laser irradiation did not affect Streptococcus mutans and S. sanguinis adhesion.

On the tribological behavior of retrieved hip femoral heads affected by metallic debris. A comparative investigation by stylus and optical profilometer for a new roughness measurement protocol

In this study, 35 retrieved ceramics femoral heads with evidence of metallic dark lines on the surface were analyzed. The surface roughness of these femoral heads was acquired using both a stylus contact profiler and an optical non-contact profilometer. The metallic deposition on hip ball surface, also known as Metal Transfer (MT), appeared as dark metallic and can occur during the surgery or during the reduction of a dislocated prosthesis. In this study, we validate a new protocol to measure surface roughness on retrieved femoral heads, by using the aforementioned two different acquisition techniques and also to investigate the hypothesis that such metal transfer retrieved ceramic femoral head is associated with increased surface roughness.All femoral components of this investigation showed remarkable differences in roughness values between MT-affected and MT-unaffected areas. The two acquisition procedures – conventional stylus and 3D confocal profilometer – confirmed a satisfying agreement, even considering the obvious resolution difference.

Fabrication of nano- to micron-sized patterns using zeolites: Its application in BSA adsorption

Nano to micron-sized zeolite A (Z-A) and silicalite (Z-SIL) patterns were generated using the combinations of electron beam lithography (EBL) or photolithography (PL) with direct attachment method to be able to generate differentiated areas on a single surface in a cheap and facile way. The possibility to generate minimum sized zeolite patterns on top of zeolite monolayers was investigated by using EBL to understand the capability of the system for the first time. Also generation of large scale zeolite patterns on top of a different zeolite monolayer was investigated by using PL allowing the generation of differentiated surfaces for various potential applications such as selective adsorption studies. With this combination, it was shown that creating 3D zeolite architectures of different types with a perfect control in all dimensions was possible without the using any chemical linker. In order to test the potential different behaviors that zeolites of different properties are offering in the adsorption of biomolecules, zeolite patterned surfaces developed by PL were subjected to adsorption studies with bovine serum albumin (BSA). Irrespective of zeolite type, BSA always preferred the patterned regions rather than the underlying zeolite monolayers. It can be speculated that the obtained difference in roughness values facilitates the protein to be selectively adsorbed onto surfaces with increased roughness, i.e., the patterned regions. Moreover, we observed ∼2-fold fluorescence intensity difference between Z-SIL and Z-A patterns, which were subjected to FITC-BSA solution. Hydrophobic interactions and charge repulsion are considered as two critical forces responsible for the observed adsorption differences.

Model Calibration as a Tool for Leakage Identification in WDS: A Real Case Study

Water leakage detection is important for a proper management of water distribution systems (WDS). This paper proposes the a pplication of the leak detection approach based on a new Bayesian calibration methodology. The methodology uses a new developed index Π, which takes into account the difference in roughness values in pipes of the calibrated models with and w ithout leaks. The case study is referred to a real network and is presented to demonstrate how the approach can be used in id entifying pipes with losses. The approach starts with the UNINET calibration method followed by the analysis of sensitivity matrices. The case study proves that the approach is effective in finding leaks i n real networks, but the results depend on the quality of the observed data. © 2014 The Authors. Published by Elsevier Ltd. Peer-review under responsibility of the Organizing Committee of WDSA 2014.

Does drainage hole size influence adhesion on ventricular catheters?

Ventricular catheter drainage holes of shunt systems used to treat hydrocephalus obstruct with tissue commonly comprising monocytes/macrophages, astrocytes, and giant cells. Despite high rates of obstruction, very few studies have manipulated drainage hole orientation, number, position, or diameter. By altering the hole diameter but maintaining a constant hole surface area, we manipulated shear stress through the holes, which we hypothesized would change the degree of macrophage and astrocyte attachment. First, a hole fabrication method was chosen from two fabrication techniques including punched holes in catheter tubing and constructed holes using nanofabrication techniques. Punched holes were chosen to vary hole size from 282 to 975μm because (1) samples were geometrically similar to commercially available ventricular catheters without significant microscopic differences in roughness values and (2) total macrophage and astrocyte adhesion on the punched holes was not significantly different from adhesion on the commercially available catheters. Overall adhesion from least to most adherent appeared to follow 975 < 754 ≈ 500 < 282-μm hole diameter for macrophages and 975 < 500 < 754 < 282 for astrocytes with an obvious dependency on catheter orientation with respect to the horizontal; a dependency to the proximity of the hole to the catheter tip was not observed. This study suggests that macrophage and astrocyte adhesion generally decreases with increasing hole diameter under flow conditions and underscores the necessity for future work to examine how hole diameter impacts inflammatory-based shunt obstruction.

Some improvement in Fe/Si multilayered neutron polarizor by modified sputtering geometry

Aperture geometry of magnetron sputtering unit was modified by insertion of longitudinal [B] and transverse [A] slits with respect to the motion of substrate. Fe-, Si-mono and Fe/Si multilayer [Fe (70 Å)/Si (50 Å)] 10 (called ML70) were grown with and without modified apertures. Maximum stress anisotropy was found in samples prepared with transverse modified aperture [A]. X-ray reflectometry (XRR) results showed a marked difference in roughness values of interdiffusion layers Fe- Si and Si- Fe. Magnetic measurements showed coercive field strength of 50 Oe in ML70 prepared by modified aperture geometry Fe[A]/Si[O]. A significant improvement in the neutron polarization efficiency is observed in multilayer ML70 with the use of modified aperture geometry as compared to similar sample prepared by normal aperture.

Surface roughness of impression materials and dental stones scanned by non-contacting laser profilometry

Objective To analyze differences in the way dental materials digitize on a non-contacting laser profilometer (NCLP). Methods Three Type IV dental stones and 15 impression materials were mixed according to the manufacturer's instructions and expressed against a glass block to record its surface characteristics. From each material an area of 6 × 40 mm was scanned on the NCLP and the Ra, Rq and Rt roughness values measured from 20 randomly selected transverse profiles. The surface of the impression materials was subsequently poured in Moonstone™ (Bracon Ltd., Etchingham, England) dental stone and the same roughness values obtained from these casts. Differences in roughness values from the dental materials were compared using ANOVA and differences in roughness between impression materials and the Moonstone™ casts compared using paired t-tests. Results There were significant differences in roughness values between individual materials within each type (impression material or dental stone) ( p < 0.05). The roughness of the dental stones varied between Ra = 0.87 and 0.99 μm, Rq = 1.09 and 1.23 μm, and Rt = 5.70 and 6.51 μm. The roughness values of the impression materials varied between Ra = 0.75 and 4.56 μm; Rq = 0.95 and 6.27 μm and Rt = 4.70 and 39.31 μm. Darker materials showed higher roughness values compared to lighter materials ( p < 0.05). The roughness of the Moonstone™ casts varied between Ra = 0.80 and 0.98 μm; Rq = 1.01 and 1.22 μm, and Rt = 5.04 and 6.38 μm. Roughness values of some impression materials were statistically significantly lower when the surface was reproduced in Moonstone™ ( p < 0.01). Significance Digitization of dental materials on optical profilometers was affected by color and transparency.

Evaluation of surface quality of some Malaysian species as function of outdoor exposure

Abstract In this study influence of outdoor exposure on surface quality of five Malaysian species, Merbau ( Intsia palembanica ), dark red meranti ( Shorea spp.), balau ( Shorea spp.) keranji ( Dialium spp.), and keruing ( Dipterocarpus spp.) were evaluated. Surface roughness of the samples exposed to outdoor environment ranging from 1 week to 4 weeks were determined using a stylus type equipment. Three roughness parameters average roughness ( R a ), mean peak-to-valley height ( R z ), and maximum roughness ( R max ) calculated from the surface profiles of the samples employing a profilometer were used for the analyses. Control samples of keranji had the smoothest surface with an average R a value of 3.90 μm while keruing had the roughest surface with 8.20 μm among five species. None of the samples from five different species resulted in significant differences in roughness values within 1-week interval during the outdoor exposure at 95% confidence level. Roughness measurements taken from the surface of control samples and samples exposed for 4-week outdoor from belau, keruing, and dark red meranti showed significant difference at 95% confidence level. These differences were not significant in the case of merbau and keranji. Based on the findings from this study it appears that stylus method can be used to evaluate surface quality of various tropical species as function of outdoor exposure.

Brushing Effect of Abrasive Dentifrices during At-home Bleaching with 10% Carbamide Peroxide on Enamel Surface Roughness

During tooth bleaching abrasive dentifrices might change the outer superficial enamel. The aim of this in vitro study was to evaluate the roughness of human enamel exposed to a 10% carbamide peroxide bleaching agent at different times and submitted to different superficial cleaning treatments. The study consisted of 60 sound human enamel slabs, randomly assigned to different treatment groups: G1--not brushed; G2--brushed with a fluoride abrasive dentifrice; G3--brushed with a non-fluoride abrasive dentifrice; and G4--brushed without a dentifrice. There were 15 enamel slabs per group. Slabs of molar teeth were obtained and sequentially polished with sandpaper and abrasive pastes. A perfilometer was used to obtain the mean of Ra value on the surface of each specimen to initial and experimental times. Bleaching was performed on the enamel surface for six hours daily. After that, each slab received a cleaning surface treatment and was stored in artificial saliva. Analysis of variance (ANOVA) and Tukey's HSD hoc analysis (alpha =0.05) revealed significant differences in roughness values over time for enamel bleached and treated with different superficial cleaning methods. G1 and G4 showed no significant differences in roughness over time, G2 and G3 showed a significant increase in the surface roughness values. This in vitro investigation showed the sole use of 10% carbamide peroxide did not alter the enamel surface roughness, but the cleaning treatments that employed the use of brushing with abrasive dentifrices resulted in a significant increase of enamel surface roughness.

Patients' perception of the roughness of restoratives

Objective To determine a threshold of detection value for surface roughness of restorations by patients using their tongue. Method Samples of composite resin were finished with differing grades of abrasive. The surface roughness (Ra) was measured and representative scanning electro-micrographs taken. These were compared with labial enamel. Twenty-five volunteers were asked to rank them in order of perceived roughness using the tip of their tongue. Results These showed that the 60% of volunteers were able to rank the specimens correctly, and were able to distinguish differences in roughness values from between 0.25 and 0.50 μm. This range encompasses that of natural enamel. Conclusions The subjects were able to distinguish lower roughness values than have previously been reported. It is concluded that when finishing restorations the surface should have a maximum roughness 0.50 μm if it is not to be detected by the patient.

The in vivo perception of roughness of restorations.

To determine a threshold of detection value for surface roughness of restorations by patients using their tongue. Samples of composite resin were finished with differing grades of abrasive. The surface roughness (Ra) was measured and representative scanning electro-micrographs taken. These were compared with labial enamel. Twenty-five volunteers were asked to rank them in order of perceived roughness using the tip of their tongue. These showed that the 60% of volunteers were able to rank the specimens correctly, and were able to distinguish differences in roughness values from between 0.25 and 0.50 microm. This range encompasses that of natural enamel. The subjects were able to distinguish lower roughness values than have previously been reported. It is concluded that when finishing restorations the surface should have a maximum roughness 0.50 microm if it is not to be detected by the patient.