scholarly journals Bacterial Adhesion and Surface Roughness for Different Clinical Techniques for Acrylic Polymethyl Methacrylate

2016 ◽  
Vol 2016 ◽  
pp. 1-6 ◽  
Author(s):  
Lucas Costa de Medeiros Dantas ◽  
João Paulo da Silva-Neto ◽  
Talita Souza Dantas ◽  
Lucas Zago Naves ◽  
Flávio Domingues das Neves ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Surface Roughness ◽  
Bacterial Adhesion ◽  
Surface Finishing ◽  
Fabrication Method ◽  
The Mean ◽  
One Way Anova ◽  
Roughness Measurements ◽  
Scanning Electron

This study sought to assess the effect of different surface finishing and polishing protocols on the surface roughness and bacterial adhesion (S. sanguinis) to polymethyl methacrylates (PMMA). Fifty specimens were divided into 5 groups (n=10) according to their fabrication method and surface finishing protocol: LP (3 : 1 ratio and laboratory polishing), NF (Nealon technique and finishing), NP (Nealon technique and manual polishing), MF (3 : 1 ratio and manual finishing), and MP (3 : 1 ratio and manual polishing). For each group, five specimens were submitted to bacterial adhesion tests and analyzed by scanning electron microscopy (SEM). Two additional specimens were subjected to surface topography analysis by SEM and the remaining three specimens were subjected to surface roughness measurements. Data were compared by one-way ANOVA. The mean bacterial counts were as follows: NF,19.6±3.05; MP,5.36±2.08; NP,4.96±1.93; MF,7.36±2.45; and LP,1.56±0.62(CFU). The mean surface roughness values were as follows: NF,3.23±0.15; MP,0.52±0.05; NP,0.60±0.08; MF,2.69±0.12; and LP,0.07±0.02(μm). A reduction in the surface roughness was observed to be directly related to a decrease in bacterial adhesion. It was verified that the laboratory processing of PMMA might decrease the surface roughness and consequently the adhesion ofS. sanguinisto this material.

Effect of Vanadium Addition on the Surface Roughness and Fatigue Crack Propagation in a Railroad Wheel Using Twin Disc Wear Test

2019 ◽  
Vol 391 ◽  
pp. 66-73 ◽  
Author(s):  
A.B. Rezende ◽  
G.A. Amorim ◽  
D.J. Minicucci ◽  
S.T. Fonseca ◽  
P.R. Mei
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Surface Roughness ◽  
Wear Test ◽  
Railroad Wheel ◽  
Roughness Parameters ◽  
Small Cracks ◽  
Sliding Test ◽  
Roughness Measurements ◽  
Scanning Electron

To verify the effect of 0.13 % vanadium addition (% in weight) on the wear resistance of a railroad wheel steel with 0.7 % carbon, twin-disc rolling-sliding test were performed. These two steels were named 7V and 7C. The test discs were analyzed to verify the superficial conditions and wear mechanisms using SEM (Scanning Electron Microscopy) and roughness measurements. After 100,000 cycles running it was concluded that without the presence of debris, the 7V steel presented a reduction in 35 % the mass loss compared to 7C steel. For the 7V steel, in the test without debris, the discs presented small cracks (10 μm long), very near (3 μm deep) the surface, but in the test with the presence of debris, the disc surfaces presented delaminated material and long cracks (100 μm long) faraway from surface (up to 72 μm deep). The presence of debris also increased the roughness parameters in 7V steel: average Rz jumped from near 6 μm in the steel without debris to near 26 μm in the steel with debris.

Scanning Electron Microscopy and Optical Profilometry of Electropolished Additively Manufactured 316 Steel Components

2018 ◽  
Author(s):  
Pawan Tyagi ◽  
Tobias Goulet ◽  
Denikka Brent ◽  
Kate Klein ◽  
Francisco Garcia-Moreno
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Surface Roughness ◽  
Smooth Surface ◽  
High Surface ◽  
Fatigue Loading ◽  
Surface Finishing ◽  
Optical Profilometry ◽  
Premature Failure ◽  
Scanning Electron

Additive manufacturing (AM) can produce highly complex engineering components that are either extremely challenging for the conventional subtractive manufacturing route or not possible otherwise. High surface roughness can make an AM component highly vulnerable to premature failure during fatigue loading. Post-processing aiming to reduce surface roughness is essential to make as produced AM parts functional. We have explored electropolishing route to achieve optimum surface roughness and surface chemistry. We have performed electropolishing treatment on the steel AM parts around 70 °C in an electrolyte comprising the phosphoric acid and sulfuric acid. Profilometry and scanning electron microscopy were performed to study the electropolished and unpolished areas. Optical profilometry study showed that one needs to remove nearly ∼200 μm material from the surface to achieve very smooth surface. Electropolishing was effective in reducing the surface Ra roughness from ∼2 μm rms to ∼0.07 μm rms. Such low rms roughness makes an AM component suitable for almost every engineering application for which a smooth surface is required. Scanning electron microscopy revealed that electropolished area on AM component possessed distinctively different microstructure as compared to the untreated surface of an AM component. We also conducted the compositional analysis of the electropolished area to investigate the possibility of residual contamination from the electropolishing process. Our study revealed that electropolishing is a highly promising route for improving the surface finishing of AM components.

scholarly journals The force effects of two types of polyethylene terephthalate glyc-olmodified clear aligners immersed in artificial saliva

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Biao Xiang ◽  
Xingxing Wang ◽  
Gang Wu ◽  
Yichen Xu ◽  
Menghan Wang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Polyethylene Terephthalate ◽  
Artificial Saliva ◽  
Orthodontic Force ◽  
The Mean ◽  
The Stability ◽  
Scanning Electron

AbstractNumerous factors can influence the force exerted by clear aligners on teeth. This study aimed to investigate the stability of the force delivered by two different material appliances. 90 clear aligners with 2 materials and three different activations were designed and fabricated. Then, a device was employed to measure the force generated by the two types of PET-G material appliances immersed in artificial saliva for 0, 3, 7, 10, 14 days. Scanning electron microscopy was applied to observe the morphologic alterations on the aligner surfaces, respectively. The forces generated by different activation appliance exhibited differently, 0.0 mm < 0.1 mm < 0.2 mm. In addition, increasing the immersion times and the orthodontic force also decreased, but the forces decreased differently. Compared with the forces of conventional PETG appliances with 0.20 mm activation, the modified PETG appliances with the same activation exhibited significantly higher mean force. When comparing the mean force for modified PETG appliances after 10 and 14 days with conventional PETG appliances, the delivery forces exhibited significant differences (P < 0.05). The force delivered by both materials decreased obviously following artificial saliva immersion, and the force generated by modified aligners exhibited better stability than conventional aligners.

scholarly journals Comparison of the Enamel Surface Roughness from Different Polishing Methods: Scanning Electron Microscopy and Atomic Force Microscopy Investigation

2020 ◽  
Vol 14 (02) ◽  
pp. 299-305
Author(s):  
Kiatanan Sugsompian ◽  
Ratchawan Tansalarak ◽  
Thosapol Piyapattamin
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Surface Roughness ◽  
Atomic Force Microscopy ◽  
Enamel Surface ◽  
Similar Data ◽  
Force Microscopy ◽  
Atomic Force ◽  
Significant Difference ◽  
Scanning Electron

Abstract Objective This study aimed to compare the enamel surface roughness created by four polishing methods after debonding, by using scanning electron microscopy (SEM) and atomic force microscopy (AFM). Materials and Methods Four experimental polishing groups (Sof-Lex disc, SD; sandblaster, SB; tungsten carbide bur, TB; and white stone bur, WB) and one control group were selected from 100 premolars (n = 20/group). The experimental teeth were bonded with a bracket, thermocycled, and debonded. Residual adhesive was removed by either of the respective methods. Pre and postdebonding root mean square (Rq) values were obtained from AFM evaluations. All specimens were examined and evaluated with SEM using a modified enamel surface index (modified ESI). Statistical Analysis Differences among the polishing methods were compared with analysis of variance and Fisher’s least significant difference test at p < 0.05. Results Both microscopic evaluations indicated that the surface with the greatest roughness herein belonged to the SD group, followed by that for SB, TB, and WB groups. AFM measurements indicated a maximum postdebonding Rq herein for the WB group and a significantly greater surface roughness for the TB and WB groups than for the SD and SB groups. Among the experimental groups, SEM followed by modified ESI evaluations revealed similar data to those obtained with AFM. Significant differences were seen among all paired groups, except for that between the SB and TB groups. Conclusion Within the limitations of this study, all four polishing methods were concluded to be clinically acceptable for removing residual orthodontic adhesives.

Influence of Titanium Alloying Element Substrata on Bacterial Adhesion

2012 ◽  
Vol 535-537 ◽  
pp. 992-995
Author(s):  
Kun Mediaswanti ◽  
Vi Khanh Truong ◽  
Jafar Hasan ◽  
Elena P. Ivanova ◽  
Francois Malherbe ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Staphylococcus Aureus ◽  
Bacterial Adhesion ◽  
Infection Risk ◽  
Bacterial Attachment ◽  
Bacterial Strains ◽  
Alloying Element ◽  
Bacteria Adhesion ◽  
Scanning Electron

Titanium and titanium alloys have been widely employed in many load-bearing orthopaedic applications due to their excellent strength and corrosion resistance. However, postimplantation infections might occur even though considerable studies have been made. Choosing a bio-friendly alloying element is one way to reduce infection risk. The aim of this study is to evaluate the extent of bacterial attachment on titanium, tantalum, niobium and tin surfaces. Two pathogenic bacterial strains, namely Staphylococcus aureus CIP 65.8T and Pseudomonas aeruginosa ATCC 9027, were used in this study. Quantification of bacterial attachment was performed using scanning electron microscopy. Results indicated that the surface chemistry and topography of the investigated materials significantly influence the degree of P. aeruginosa and S. aureus adhesion; however, surface wettability did not show a significant impact upon bacterial retention. In this study, tin was shown to be the most attractive material for bacteria adhesion but tantalum limits the bacterial adhesion. Therefore, it is suggested to limit the amount of tin as an titanium alloying element due to its nature to attract P. aeruginosa and S. aureus adhesion.

scholarly journals In VitroAdherence of Oral Bacteria to Different Types of Tongue Piercings

2016 ◽  
Vol 2016 ◽  
pp. 1-6 ◽  
Author(s):  
Lucas Pereira Borges ◽  
Julio Cesar Campos Ferreira-Filho ◽  
Julia Medeiros Martins ◽  
Caroline Vieira Alves ◽  
Bianca Marques Santiago ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Bacterial Adhesion ◽  
Oral Bacteria ◽  
The Other ◽  
Control Group ◽  
Colony Forming Units ◽  
Different Types ◽  
Scanning Electron

The purpose of this work was to verifyin vitroadherence ofE. corrodensandS. oralisto the surface of tongue piercings made of surgical steel, titanium, Bioplast, and Teflon. For this, 160 piercings were used for the count of Colony Forming Units (CFU) and 32 piercings for analysis under scanning electron microscopy. Of these, 96 (24 of each type) were individually incubated in 5 mL of BHI broth and 50 μL of inoculum at 37°C/24 h. The other 96 piercings formed the control group and were individually incubated in 5 mL of BHI broth at 37°C/24 h. Plates were incubated at 37°C/48 h for counting of CFU/mL and data were submitted to statistical analysis (pvalue<0.05). ForE. corrodens, difference among types of material was observed (p<0.001) and titanium and surgical steel showed lower bacterial adherence. The adherence ofS. oralisdiffered among piercings, showing lower colonization (p<0.007) in titanium and surgical steel piercings. The four types of piercings were susceptible to colonization byE. corrodensandS. oralis, and bacterial adhesion was more significant in those made of Bioplast and Teflon. The piercings presented bacterial colonies on their surface, being higher in plastic piercings probably due to their uneven and rough surface.

scholarly journals Penetration of Different Impression Materials into Exposed Dentinal Tubules during the Impression Procedure

Materials ◽  
2020 ◽  
Vol 13 (6) ◽  
pp. 1321 ◽  
Author(s):  
Bruna Sinjari ◽  
Gianmaria D’Addazio ◽  
Edit Xhajanka ◽  
Sergio Caputi ◽  
Giuseppe Varvara ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Fractal Dimensions ◽  
Excellent Performance ◽  
Dentinal Tubules ◽  
Impression Materials ◽  
Electron Microscopy Analysis ◽  
Microscopy Analysis ◽  
The Mean ◽  
Scanning Electron

Adhesive restorations have been shown to guarantee excellent performance and longevity, although this comes with some disadvantages. Among these, the vulnerability of dentine to different agents has been widely evaluated. The aim of this study was to evaluate the possible penetration of impression materials into freshly cut dentine. Dentine from 27 teeth was impressed with polyether (Impregum Penta L) (nine teeth) and with polyvinyl siloxane (Aquasil Ultra LV) (nine teeth). The surface of nine teeth after the impressions were used as the control. Specifically, the extroflections caused by the imprinting of the dentinal tubules on the impression material, the so-called impression tags, were measured. Furthermore, the presence of the material inside the tubules was examined. Scanning electron microscopy analysis showed material tags for all of the experimental groups. The mean lengths (±SD) were 22.6 (±11.0) µm for polyether, 21.8 (±12.8) µm for polyvinyl siloxane and 11.3 (±7.0) µm for the tooth control, with mean diameters (±SD) of 2.8 (±0.5), 2.4 (±0.7) and 3.1 (±0.7) µm, respectively. Fractal analysis showed fractal dimensions of 1.78 (±0.03), 1.77 (±0.03) and 1.71 (±0.03), respectively. These data demonstrated that the impression materials can remain inside the dentinal tubules, which can adversely affect the adhesive procedures.

scholarly journals Viability of Sirococcus clavigignenti-juglandacearum Conidia on Exoskeletons of Three Coleopteran Species

Plant Disease ◽  
2004 ◽  
Vol 88 (10) ◽  
pp. 1085-1091 ◽  
Author(s):  
J. E. Stewart ◽  
S. Halik ◽  
D. R. Bergdahl
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Vector Potential ◽  
Insect Species ◽  
Juglans Cinerea ◽  
The Mean ◽  
Scanning Electron ◽  
Butternut Canker

Butternut canker, caused by Sirococcus clavigignenti-juglandacearum, is the primary cause of decline of butternut (Juglans cinerea). Conidia of the fungus have been isolated from several insect species. The vector potential of three species of Coleoptera, Astylopsis macula, Eubulus parochus, and Glischrochilus sanguinolentus, was studied during 2001 and 2002. Beetles were collected, rinsed, and artificially inoculated with conidia. All three species carried viable conidia up to 16 days. The mean number of conidia carried per beetle in 2001 was as follows: 3.21 million at 0 h to 11,371 at 384 h for A. macula; 3.91 million at 0 h to 57 at 384 h for E. parochus; and 355,742 at 0 h to 314 at 384 h for G. sanguinolentus. In 2002, the numbers were: 1.42 million at 0 h to 2,814 at 384 h for A. macula; 1.29 million at 0 h to 85 at 384 h for E. parochus; and 72,342 at 0 h to 0 at 192 h for G. sanguinolentus. Using scanning electron microscopy, conidia were observed on the abdomen, thorax, and legs of artificially inoculated individuals of each species and on the thorax and abdomen of field-collected A. macula and E. parochus. These data suggest that all three species are potential vectors of S. clavigignenti-juglandacearum; however, A. macula and E. parochus may be more effective vectors.

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