scholarly journals Evaluation of Surface Roughness of a Ni-Cr Alloy Treated With the Nd/YAG Laser and the Sandblast Technique

2021 ◽  
Vol 12 (1) ◽  
pp. e69-e69
Author(s):  
Elnaz Moslehifard ◽  
Mir Mahdi Seyyedashrafi ◽  
Nasim Khosronejad
Keyword(s):  
Surface Roughness ◽  
Nd:Yag Laser ◽  
Study Groups ◽  
Spot Size ◽  
Chromium Alloy ◽  
Air Abrasion ◽  
Average Roughness ◽  
Average Value ◽  
Nickel Chromium ◽  
Group B

Introduction: This study was to assess the effect of various output parameters of laser treatment on roughening the surface of a commercial nickel-chromium (Ni-Cr) alloy as compared to the sandblasting technique. Materials and Methods: Ninety-six disk-shaped (5 mm diameter and 2 mm thickness) specimens in total were made of a nickel-chromium alloy by using the lost-wax technique. Air-abrasion surface treatment was used for sixteen specimens. Specimens were divided into six groups; one of them was sandblasted and the rest were irradiated by different Nd:YAG laser output parameters as follows: Group A: energy: 122 mJ, frequency: 20 Hz, irradiation duration: 20 seconds, spot size: 1.5 mm; Group B: energy: 122 mJ, frequency: 20 Hz, irradiation duration: 20 seconds, spot size: 3.5 mm; Group C: energy: 122 mJ, frequency: 10 Hz, irradiation duration: 20 seconds, spot size: 3.5 mm; Group D: energy: 102 mJ, frequency: 10 Hz, irradiation duration: 20 seconds, spot size: 3 mm; Group E: energy: 102 mJ, frequency: 20 Hz, irradiation duration: 20 seconds, spot size: 3 mm. The surface roughness of all surface-treated specimens was evaluated by using a profilometer, and their average roughness (Ra) was calculated. The average value of each group was analyzed by t test and one-way ANOVA (SPSS 17). Results: Significant differences (P<0.05) were observed between the study groups. The highest Ra was achieved for the sandblasted group. The Ra value in group C was the highest value among the laser-etched groups. Conclusion: Based on the results, Nd:YAG laser irradiation increases surface roughness, but it is not as efficient as the sandblasting method as a gold standard.

Comparative evaluation of surface roughness and texture of polished nanofill and nanohybrid composites using profilometer and scanning electron microscope: in - vitro study

2017 ◽  
Vol 9 (2) ◽  
pp. 4-10
Author(s):  
Krishna Prasada L ◽  
Jyothsna S Jathanna ◽  
Naveen Kumar ◽  
Ramya M.K ◽  
Elizabeth Issac
Keyword(s):  
Surface Roughness ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Resin Composite ◽  
In Vitro Study ◽  
Average Value ◽  
Three Samples ◽  
Group B ◽  
Scanning Electron

BACKGROUND: To determine the effectiveness of three polishing systems on three different composite materials by evaluating surface roughness using a Profilometer and Scanning electron microscope. METHODOLOGY: A total of Sixty-three resin composite disks were prepared in rectangular acrylic mould of 8×2mm dimension, with 4mm thickness. Specimens were made of light activated resin composite Filtek Z-250-XT, Tetric-N-Ceram bulkfill, Ceram X Duo. The sixty-three samples were divided into three groups of twenty-one samples each i.e. Group A (Filtek Z-250-XT), Group B (TetricN-Ceram bulkfill) and Group C (Ceram-X-Duo).Out of 21 samples of each of the material, 7 specimens were polished with multi enhance polishing agents, 7 specimens were polished with super snap polishing agents and 7 specimens were polished with sof-lexdiscs.Surface roughness of each sample after polishingwasevaluatedusingProfilometer and Scanning electron microscope. RESULTS: One-way anova and kruskalwallis test was used for statistical analysis. Ceram-X-Duo gave least roughness average value with Super snap polishing system when compared to multi enhance and sof-lex polishing system. CONCLUSION: Super snap polishing system is a better polishing system than multi enhance and soflex and Ceram-X-Duo composite material offers better polishability compared to Filtek Z-250-XT and Tetric-N-Ceram bulk fill.

scholarly journals Nickel, Chromium and Iron Levels in the Saliva of Patients with Simulated Fixed Orthodontic Appliances

2008 ◽  
Vol 78 (2) ◽  
pp. 345-350 ◽  
Author(s):  
Rodrigo Matos de Souza ◽  
Luciane Macedo de Menezes
Keyword(s):  
Study Groups ◽  
Atomic Absorption Spectrophotometry ◽  
Nonparametric Tests ◽  
Orthodontic Appliances ◽  
Aisi 316L ◽  
Nickel Chromium ◽  
Fixed Orthodontic Appliances ◽  
Group B ◽  
Removable Appliance

Abstract Objective: To assess the in vivo release of nickel, chromium, and iron ions into saliva by different metallic brackets. Materials and Methods: Thirty volunteers wore removable appliances with bonded brackets and were divided according to the brand of brackets: group A, 3M/Unitek (AISI 303); group B, American Orthodontics (AISI 316L); and group C, Dentaurum (AISI 316L). The appliances were worn for 60 days, and saliva samples were collected at the following time points: T1, before placement of the appliance; T2, after 10 minutes; T3, 24 hours; T4, 7 days; T5, 30 days; and T6, 60 days after insertion of the removable appliance. Saliva samples were analyzed for nickel, chromium, and iron by atomic absorption spectrophotometry. Statistical analysis was performed by nonparametric tests (Friedman, Mann-Whitney, Kruskal-Wallis). Results: Saliva evaluation revealed a large variation in concentration of these ions between individuals. The results also appeared to indicate an increase in nickel and chromium ions immediately after placement of the appliance (T2), but this was statistically significant only for groups B and C. There was no increase in iron levels. A tendency for increases in nickel and chromium concentrations was verified immediately after placement of the appliance, but these values are probably reduced because of biofilm formation regardless of the bracket used. Conclusion: Nickel and chromium ion concentrations increased immediately after placement of the appliance in the mouth for all study groups. There were no significant differences in the nickel, chromium, and iron levels released by the three groups of appliances at all study periods.

INCONEL ALLOY X-750

Alloy Digest ◽  
1966 ◽  
Vol 15 (7) ◽  
Keyword(s):  
Gas Turbines ◽  
Rupture Strength ◽  
Low Cost ◽  
High Strength ◽  
Heat Treating ◽  
Chromium Alloy ◽  
Cryogenic Temperatures ◽  
Inconel Alloy ◽  
Nickel Chromium ◽  
Corrosion And Oxidation

Abstract INCONEL alloy X-750 is an age-hardenable, nickel-chromium alloy used for its corrosion and oxidation resistance and high creep rupture strength at temperature up to 1500 F. It also has excellent properties at cryogenic temperatures. It was originally developed for use in gas turbines, but because of its low cost, high strength and weldability it has become the standards choice for a wide variety of applications. This datasheet provides information on composition, physical properties, elasticity, and tensile properties as well as creep and fatigue. It also includes information on forming, heat treating, machining, joining, and surface treatment. Filing Code: Ni-115. Producer or source: Huntington Alloy Products Division, An INCO Company.

INCONEL ALLOY 671

Alloy Digest ◽  
1972 ◽  
Vol 21 (10) ◽  
Keyword(s):  
Corrosion Resistance ◽  
High Temperature ◽  
Physical Properties ◽  
Surface Treatment ◽  
Heat Treating ◽  
High Temperature Corrosion ◽  
Chromium Alloy ◽  
Inconel Alloy ◽  
Nickel Chromium ◽  
Temperature Performance

Abstract INCONEL ALLOY 671 is a nickel-chromium alloy having excellent resistance to high-temperature corrosion. This datasheet provides information on composition, physical properties, hardness, and tensile properties as well as creep. It also includes information on high temperature performance and corrosion resistance as well as forming, heat treating, machining, joining, and surface treatment. Filing Code: Ni-180. Producer or source: Huntington Alloy Products Division, An INCO Company.

SANICRO 31

Alloy Digest ◽  
1965 ◽  
Vol 14 (9) ◽  
Keyword(s):  
Mechanical Properties ◽  
Petrochemical Industry ◽  
Elevated Temperatures ◽  
Heat Treating ◽  
Chromium Alloy ◽  
Good Resistance ◽  
Nickel Chromium ◽  
Temperature Performance ◽  
Iron Nickel ◽  
Corrosion And Oxidation

Abstract SANDVIK SANICRO 31 is an iron-nickel-chromium alloy having good resistance to corrosion and oxidation and good mechanical properties at elevated temperatures. It is recommended for electrical sheathing, pyrometer tubes, equipment for heat treating and furnace tubes and other equipment in the petrochemical industry. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on high temperature performance and corrosion resistance as well as forming, heat treating, machining, joining, and surface treatment. Filing Code: SS-172. Producer or source: Sandvik.

scholarly journals The Role of Obesity in Predicting the Clinical Outcomes of COVID-19

Obesity Facts ◽  
2021 ◽  
pp. 1-9
Author(s):  
Serdar Sahin ◽  
Havva Sezer ◽  
Ebru Cicek ◽  
Yeliz Yagız Ozogul ◽  
Murat Yildirim ◽  
...  
Keyword(s):  
Clinical Outcomes ◽  
Health Care Providers ◽  
Study Groups ◽  
Normal Weight ◽  
Overweight And Obesity ◽  
Care Providers ◽  
Significant Difference ◽  
Group A ◽  
Group B ◽  
Group D

<b><i>Introduction:</i></b> The aim of this was to describe the predictors of mortality related to COVID-19 infection and to evaluate the association between overweight, obesity, and clinical outcomes of COVID-19. <b><i>Methods:</i></b> We included the patients &#x3e;18 years of age, with at least one positive SARS-CoV-2 reverse transcriptase-polymerase chain reaction. Patients were grouped according to body mass index values as normal weight &#x3c;25 kg/m<sup>2</sup> (Group A), overweight from 25 to &#x3c;30 kg/m<sup>2</sup> (Group B), Class I obesity 30 to &#x3c;35 kg/m<sup>2</sup> (Group C), and ≥35 kg/m<sup>2</sup> (Group D). Mortality, clinical outcomes, laboratory parameters, and comorbidities were compared among 4 groups. <b><i>Results:</i></b> There was no significant difference among study groups in terms of mortality. Noninvasive mechanical ventilation requirement was higher in group B and D than group A, while it was higher in Group D than Group C (Group B vs. Group A [<i>p</i> = 0.017], Group D vs. Group A [<i>p</i> = 0.001], and Group D vs. Group C [<i>p</i> = 0.016]). Lung involvement was less common in Group A, and presence of hypoxia was more common in Group D (Group B vs. Group A [<i>p</i> = 0.025], Group D vs. Group A [<i>p</i> &#x3c; 0.001], Group D vs. Group B [<i>p</i> = 0.006], and Group D vs. Group C [<i>p</i> = 0.014]). The hospitalization rate was lower in Group A than in the other groups; in addition, patients in Group D have the highest rate of hospitalization (Group B vs. Group A [<i>p</i> &#x3c; 0.001], Group C vs. Group A [<i>p</i> &#x3c; 0.001], Group D vs. Group A [<i>p</i> &#x3c; 0.001], Group D vs. Group B [<i>p</i> &#x3c; 0.001], and Group D vs. Group C [<i>p</i> = 0.010]). <b><i>Conclusion:</i></b> COVID-19 patients with overweight and obesity presented with more severe clinical findings. Health-care providers should take into account that people living with overweight and obesity are at higher risk for COVID-19 and its complications.

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