scholarly journals Accelerated Aging Effects on Surface Hardness and Roughness of Lingual Retainer Adhesives

2008 ◽  
Vol 78 (1) ◽  
pp. 140-144 ◽  
Author(s):  
Sabri Ilhan Ramoglu ◽  
Serdar Usumez ◽  
Tamer Buyukyilmaz
Keyword(s):  
Surface Roughness ◽  
Vickers Hardness ◽  
Statistical Significance ◽  
Accelerated Aging ◽  
Aging Effects ◽  
Surface Microhardness ◽  
Halogen Light ◽  
Before And After ◽  
The Mean ◽  
Lingual Retainer

Abstract Objective: To test the null hypothesis that accelerated aging has no effect on the surface microhardness and roughness of two light-cured lingual retainer adhesives. Materials and Methods: Ten samples of light-cured materials, Transbond Lingual Retainer (3M Unitek) and Light Cure Retainer (Reliance) were cured with a halogen light for 40 seconds. Vickers hardness and surface roughness were measured before and after accelerated aging of 300 hours in a weathering tester. Differences between mean values were analyzed for statistical significance using a t-test. The level of statistical significance was set at P < .05. Results: The mean Vickers hardness of Transbond Lingual Retainer was 62.8 ± 3.5 and 79.6 ± 4.9 before and after aging, respectively. The mean Vickers hardness of Light Cure Retainer was 40.3 ± 2.6 and 58.3 ± 4.3 before and after aging, respectively. Differences in both groups were statistically significant (P < .001). Following aging, mean surface roughness was changed from 0.039 μm to 0.121 μm and from 0.021 μm to 0.031 μm for Transbond Lingual Retainer and Light Cure Retainer, respectively. The roughening of Transbond Lingual Retainer with aging was statistically significant (P < .05), while the change in the surface roughness of Light Cure Retainer was not (P > .05). Conclusions: Accelerated aging significantly increased the surface microhardness of both light-cured retainer adhesives tested. It also significantly increased the surface roughness of the Transbond Lingual Retainer.

EXPERIMENTAL INVESTIGATION OF THE DURABILITY OF LOAD BEARING TIMBER-GLASS COMPOSITES UNDER THE EFFECTS OF ACCELERATED AGING

2019 ◽  
Vol 14 (2) ◽  
pp. 45-59 ◽  
Author(s):  
Halet Almila Arda Buyuktaskin ◽  
Mehmet Serkan Yatagan ◽  
Gulseren Erol Soyoz ◽  
Leyla Tanacan ◽  
Morvarid Dilmaghani
Keyword(s):  
Raw Materials ◽  
Accelerated Aging ◽  
Structural Elements ◽  
Atmospheric Conditions ◽  
Aging Effects ◽  
Glass Composite ◽  
Load Bearing ◽  
Glass Composites ◽  
Before And After

Although timber was used extensively as a structural material for traditional buildings in Turkey in the past, usage of structural timber decreased significantly over time and timber has been largely replaced by other materials. As timber is a natural, durable and sustainable material, it would be desirable to re-introduce timber structural elements to contemporary construction in a form that is appealing to industry. Timber-glass composite structural elements are potentially a good candidate for this purpose. To that end, a series of tests were conducted on load-bearing timber-glass composites in order to understand the long–term structural performance of the composite material under atmospheric conditions; to decrease the recurring cost of repair and maintenance; and to minimize the exhaustion of raw materials and energy. In this paper, the first part of this experimental work is presented, which focuses on the durability of timber-glass composite under the effects of accelerated aging, carried out on small-sized timber-glass composite specimens. Accelerated aging effects were observed under wetting-drying, freezing-thawing, UV effects, resistance to acids and high temperature. The mechanical strength of the timber-glass composite specimens before and after the effect of accelerated aging was measured by adhesion and shear strength tests and a comparative analysis of the results was carried out. The results of the experiments indicate that timber-glass composite is suitable to be used under protection from environmental conditions.

scholarly journals Biochemical Markers of Renal Hypoperfusion, Hemoconcentration, and Proteinuria after Extreme Physical Exercise

Medicina ◽  
2019 ◽  
Vol 55 (5) ◽  
pp. 154 ◽  
Author(s):  
Wojciech Wołyniec ◽  
Katarzyna Kasprowicz ◽  
Patrycja Rita-Tkachenko ◽  
Marcin Renke ◽  
Wojciech Ratkowski
Keyword(s):  
Physical Exercise ◽  
Statistical Significance ◽  
Blood Perfusion ◽  
Fractional Excretion ◽  
Creatinine Ratio ◽  
Plasma Urea ◽  
Urinary Potassium ◽  
Before And After ◽  
The Mean ◽  
Renal Hypoperfusion

Background and Objectives: Physical exercise increases the blood perfusion of muscles, but decreases the renal blood flow. There are several markers of renal hypoperfusion which are used in the differential diagnosis of acute kidney failure. Albuminuria is observed after almost any exercise. The aim of this study was to assess changes in renal hypoperfusion and albuminuria after a 100-km race. Materials and Methods: A total of 27 males who finished a 100-km run were studied. The mean age of the runners was 38.04 ± 5.64 years. The exclusion criteria were a history of kidney disease, glomerular filtration rate (GFR) <60 ml/min, and proteinuria. Blood and urine were collected before and after the race. The urinary albumin/creatinine ratio (ACR), fractional excretion of urea (FeUrea) and sodium (FeNa), plasma urea/creatinine ratio (sUrea/Cr), urine/plasma creatinine ratio (u/pCr), urinary sodium to potassium ratio (uNa/K), and urinary potassium to urinary potassium plus sodium ratio (uK/(K+Na)) were calculated. Results: After the race, significant changes in albuminuria and markers of renal hypoperfusion (FeNa, FeUrea, sUrea/Cr, u/sCr, urinary Na, uNa/K, uK/(K+Na)) were found. Fifteen runners (55.56%) had severe renal hypoperfusion (FeUrea <35, uNa/K <1, and uK/(Na+K) >0.5) after the race. The mean ACR increased from 6.28 ± 3.84 mg/g to 48.43 ± 51.64 mg/g (p < 0.001). The ACR was higher in the group with severe renal hypoperfusion (59.42 ± 59.86 vs. 34.68 ± 37.04 mg/g), but without statistical significance. Conclusions: More than 50% of the runners had severe renal hypoperfusion after extreme exercise. Changes in renal hemodynamics are probably an important, but not the only, factor of post-exercise proteinuria.

scholarly journals Efficacy and tolerability of combined medication of two different antimuscarinics for treatment of adults with idiopathic overactive bladder in whom a single agent antimuscarinic therapy failed

2013 ◽  
Vol 7 (1-2) ◽  
pp. 88 ◽  
Author(s):  
Junseok Yi ◽  
Seong Jin Jeong ◽  
Min Soo Chung ◽  
Hongzoo Park ◽  
Sang Wook Lee ◽  
...  
Keyword(s):  
Overactive Bladder ◽  
Statistical Significance ◽  
Single Agent ◽  
Clean Intermittent Catheterization ◽  
Dosage Escalation ◽  
Before And After ◽  
The Mean ◽  
Combined Medication ◽  
Voided Volume ◽  
Antimuscarinic Therapy

Objective: Recent studies have investigated a combination of two antimuscarinics for adult neurogenic bladder managed with clean intermittent catheterization or pediatric refractory overactive bladder (OAB). We assessed the efficacy and tolerability of this strategy in adults with idiopathic OAB.Methods: We reviewed 49 patients with idiopathic OAB whoreceived combined antimuscarinic medication. Patients had seriallyreceived different kinds of antimuscarinics as monotherapy, but wished to take combined medication due to a lack of sufficient subjective improvement in urgency, even with dosage escalation. Efficacy was measured by changes of episodes of urgency, daytime voiding, nocturia and mean voided volume before and after the addition of the second antimuscarinic.Results: The mean duration of combined medication was 9.3 months. After adding the second antimuscarinic, urgency per day decreased from 3.8 to 1.9 (p < 0.001) and daytime voiding decreased from 10.4 to 7.4 (p < 0.001). The number of nocturia episodes and the mean voided volume also improved, although therewas no statistical significance. Efficacy did not differ between the 29 cases, with non-selective and non-selective drugs and 20 cases with non-selective and M3 selective drugs. Thirty-three (67.3%) patients reported to have benefited from combined medication. Maximal flow rate and post-void residual volume did not change in either of the sexes. Eleven (22.4%) patients discontinued the combination due to continued ineffectiveness and dry mouth.Conclusion: This retrospective study suggests that combined medication can help adults with refractory idiopathic OAB. Combined medication was tolerated in most of our patients.

Effect of Thermal Cycling Aging on the Surface Microhardness and Roughness of Resin-Infiltrated Enamel Lesions

2021 ◽  
Vol 13 (3) ◽  
pp. 356-363
Author(s):  
Yu Wu Su ◽  
Chao Zhang ◽  
Shan Shan Liu ◽  
Liang Yue Pang ◽  
Huan Cai Lin ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Thermal Cycling ◽  
Control Group ◽  
Surface Microhardness ◽  
Suitable Material ◽  
Resin Infiltration ◽  
Enamel Caries ◽  
Caries Model ◽  
Before And After ◽  
Infiltrant Resin

With the widespread use of resin infiltration, its properties have drawn increasing attention. The objective of this study was to investigate the effect of resin infiltration on the surface microhardness and roughness of enamel lesions after thermal cycling aging. Tooth blocks were made from extracted premolars and placed into a control group, resin-infiltrated group or demineralized group. Before and after the aging procedure, the surface microhardness and surface roughness was measured. Before the aging procedure, the surface microhardness of the control group, resin-infiltrated group and demineralized group was 302.14 (±9.77) HV, 146.62 (±8.22) HV, and 28.85 (±2.21) HV (p 0.001), respectively. After the aging procedure, the surface microhardness of the control group, resin-infiltrated group and demineralized group decreased by 9.42%, 16.59%, and 20.75% ( p 0.001), respectively. Before the aging procedure, the surface roughness of the control group, resin-infiltrated group and demineralized group was 0.29 (±0.04) μm, 0.32 (±0.04) μm, and 0.39 (±0.07) μm (p = 0.009), respectively. After the aging procedure, the surface roughness of the control group, resin-infiltrated group and demineralized group increased by 9.85%, 8.31%, and 17.37% (p = 0.634), respectively. Resin infiltration can improve the surface microhardness and surface roughness of demineralized teeth in an artificial enamel caries model. The treatment also shows good aging resistance after thermal cycling. The infiltrant resin provided a suitable material for early enamel caries.

Surface Roughness and Enamel Loss with Two Microabrasion Techniques

2009 ◽  
Vol 10 (1) ◽  
pp. 58-65 ◽  
Author(s):  
Flávio Fernando Demarco ◽  
Sonia Saeger Meireles ◽  
Dárvi de Almeida André ◽  
Ferdinan Luís Leida ◽  
Jorge Saldivar Bocangel
Keyword(s):  
Surface Roughness ◽  
San Antonio ◽  
Total Surface Area ◽  
Sem Analysis ◽  
Health Science ◽  
University Of Texas ◽  
Before And After ◽  
Texas Health ◽  
The Mean ◽  
Acid Treatments

Abstract Aim The aim of this study was to evaluate and compare the surface roughness and enamel loss produced by two microabrasion techniques. Methods and Materials Bovine teeth were selected and an area was delimited for microabrasion techniques. Surface roughness was determined before and after treatment using a digital profilometer. Specimens were randomized to one of two acid treatments (n=10): 18% hydrochloric acid (HCl) and pumice or 37% phosphoric acid (H3PO4) and pumice. Acid treatments were applied using a wooden spatula for 5 seconds for a total of ten applications. Then, specimens were sectioned through the center of the demineralization area to obtain 80μm thick slices. The wear produced by the microabrasion techniques was evaluated using stereomicroscopy (40x). The greatest depth (μm) and the total surface area (μm2) of demineralization were measured using the Image Tool software (University of Texas Health Science, San Antonio, TX, USA). In addition, three specimens of each group were subjected to SEM analysis at different magnifications. Results The mean surface roughness was statistically lower for HCl than for H3PO4 (p<0.001). Deeper demineralization (p<0.003) and a larger total demineralization area was observed for HCl (p<0.005). Under SEM analysis H3PO4 showed a selective conditioning etching, while HCl exhibited a non-selective pattern. Conclusions Microabrasion using H3PO4 produced greater surface roughness but less demineralization than the microabrasion technique using HCl. Clinical Significance Both microabrasion techniques effectively remove the superficial enamel layer. However, the technique using H3PO4 was less aggressive, safer, and easier to perform. Citation Meireles SS, André DA, Leida FL, Bocangel JS, Demarco FF. Surface Roughness and Enamel Loss with Two Microabrasion Techniques. J Contemp Dent Pract 2009 January; (10)1:058-065.

Autologous Adipose Tissue Injection of Vocal Cords in Presbyphonia

2021 ◽  
pp. 019459982110452
Author(s):  
Ramón González-Herranz ◽  
Andrés Navarro-Mediano ◽  
Estefanía Hernández-García ◽  
Guillermo Plaza
Keyword(s):  
Medical Center ◽  
Statistical Significance ◽  
Vocal Folds ◽  
Demographic Variables ◽  
Long Term Results ◽  
Maximum Phonation Time ◽  
Before And After ◽  
The Mean

Objective This series evaluates the long-term results of autologous adipose injection (AAI) in patients older than 65 years with presbyphonia. Study Design Retrospective cohort study. Setting Academic secondary medical center. Methods This was a retrospective study with a minimum follow-up of 12 months. All patients underwent AAI for atrophy of both vocal folds due to presbyphonia. We measured subjective parameters as Voice Handicap Index–10 (VHI-10) or GRBAS scale (grade, roughness, breathiness, asthenia, strain) and objective measures such as maximum phonation time (MPT) or square pixel closure defect. We reviewed the medical records of patients undergoing AAI during the 2011-2018 period. An analysis of the demographic variables of the group was performed, as well as the values of VHI-10, GRBAS, and MPT, and the minimum closure defect measured in square pixels and the number of closed frames in the glottal cycle before and after the intervention. Results At 12 months, 17 of 18 patients reported subjective and VHI-10 improvement. The mean preoperative VHI-10 (26.7) was significantly higher than the postoperative value (14.4), and the GRBAS scale had a preoperative mean of 8.7 and a postoperative mean of 4.3, both with statistical significance. MPT increased from 7.7 to 12.4 seconds ( P < .0001). The minimum closure defect measurements obtained in square pixels changed from 305 to 124, achieving complete closure in 3 patients. The closed phase of the glottal cycle change from 14.3% to 38.2% after the AAI. Conclusions AAI improves long-term vocal fold closure, demonstrating utility in patients with presbyphonia.

Effect of Finishing and Polishing on the Surface Roughness and Gloss of Feldspathic Ceramic for Chairside CAD/CAM Systems

2017 ◽  
Vol 42 (2) ◽  
pp. 175-184 ◽  
Author(s):  
M Carrabba ◽  
A Vichi ◽  
G Vultaggio ◽  
S Pallari ◽  
R Paravina ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Flat Surface ◽  
Paper Surface ◽  
Before And After ◽  
Cad Cam ◽  
Ceramic Blocks ◽  
The Mean ◽  
Silicone Carbide ◽  
Cam Systems ◽  
Scanning Electron

SUMMARY Objectives: To evaluate surface roughness and gloss of feldspathic ceramic blocks for chairside CAD/CAM systems before and after finishing and polishing. Methods: VITA Mark II ceramic blocks for the CEREC CAD/CAM system were cut perpendicularly in order to obtain a total of 70 specimens (14 × 18 × 3 mm). The flat surface was roughened using a grinder/polisher with dry 120-grit silicone-carbide paper. Surface roughness and gloss were measured using a digital profilometer (Ra) and a glossmeter (GU), respectively. Specimens were randomly divided into seven groups (n=10) based on the finishing/polishing system as follows: 1) Identoflex NGPorcelain Polisher (INP), 2) Identoflex Diamond Ceramic Polisher (IDP), 3) Hiluster Polishing System (HPS), 4) OptraFine (OF), 5) Identoflex Lucent (IL), 6) VITA Akzent Glaze Spray (AGS), and 7) VITA Shading Paste and Liquid (SPL). Surface analysis was repeated after the finishing/polishing treatment, and the obtained data were compared to the baseline in order to evaluate the ΔRa and ΔGU. Results were statistically analyzed. The surface morphology was observed by scanning electron microscopy. Results: The mean surface roughness of polished systems increased in the order (statistical groups designated) SPLa &lt; ILa &lt; OFab &lt; IDPbc &lt; AGSbc &lt; INPbc &lt; HPSc and mean gloss decreased in the order AGSa &gt; SPLa &gt; OFab &gt; ILabc &gt; HPSbcd &gt; INPcd &gt; IDPd. Conclusions: The smoothest surface of CAD/CAM feldspathic ceramic blocks was achieved using the furnace-based glaze systems VITA Akzent Glaze Spray and VITA Shading Paste and Liquid and manual systems Identoflex Lucent and OptraFine.

Surface Properties and Color Stability of Resin-Infiltrated Enamel Lesions

2016 ◽  
Vol 41 (6) ◽  
pp. 617-626 ◽  
Author(s):  
X Zhao ◽  
Y-F Ren
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Surface Roughness ◽  
Water Storage ◽  
Color Stability ◽  
White Spot ◽  
Surface Microhardness ◽  
Resin Infiltration ◽  
Before And After ◽  
Scanning Electron

SUMMARY Objectives: To examine the surface topographies, microhardness, and color stability of resin-infiltrated enamel lesions before and after aging challenges in vitro using three-dimensional laser scanning profilometry, surface microhardness testing, spectrophotometry, and scanning electron microscopy. Methods: Forty human third molars were embedded in epoxy resin, and each tooth was prepared to have two white spot lesions and one sound enamel area. One white spot lesion received resin infiltration and the other was untreated. Ten specimens were subjected to thermocycling for 10,000 cycles, 10 specimens were immersed in coffee solutions, and 10 specimens were placed in water storage. Surface area roughness (Sa), Vickers microhardness (VHN), and CIE L*a*b* color values were measured on sound enamel, resin-infiltrated lesions, and untreated lesions before and after aging. The surface morphology of resin-infiltrated lesions was observed after aging under scanning electron microscopy and compared with 10 specimens that were not subjected to aging challenge. Results: Resin infiltration increased the surface microhardness of the enamel lesions from 89.3 to 212.0 VHN. The surface microhardness of resin-infiltrated enamel lesions was not significantly affected by aging. The surface roughness of resin-infiltrated lesions (0.32–0.37 μm) was greater than that of sound enamel (0.05–0.06 μm) and untreated lesions (0.12–0.13 μm). Thermocycling and water storage further increased surface roughness of resin-infiltrated surfaces. Resin-infiltrated enamel lesions showed greater discoloration than sound enamel surfaces. Surface microfissures and microcracks were observed on resin-infiltrated enamel lesions after thermocycling. Conclusions: Surface hardness of enamel lesions increased significantly after resin infiltration and remained stable following thermocycling. Surface roughness and color stability of resin-infiltrated enamel lesions were less than ideal and might further deteriorate after aging in the oral environment.

scholarly journals Influence of Different Wax Hardening Agents on Surface Roughness of Refractory Cast Investment Materials

2021 ◽  
Vol 3 (3) ◽  
pp. 91-95
Author(s):  
Zahraa Noori Yassen ◽  
Israa Mohammed Hummudi
Keyword(s):  
Surface Roughness ◽  
Surface Hardening ◽  
P Value ◽  
Before And After ◽  
Cast Model ◽  
Dipping Process ◽  
The Mean ◽  
Dental Surface ◽  
Dental Cast ◽  
Available Phosphate

Background: Phosphate-bonded investments produce a refractory cast model with rough surface and undesirable properties. Dental Surface hardening agents are then applied to refractory investment materials to enhance its properties. Purpose: compare and evaluate the effects of different dental cast hardening agents (Bees wax, Carnauba wax, and Ceresin wax) on surface roughness of refractory model investment material.  Approach: 30 specimens were constructed from commercially available phosphate bonded investment material. Specimens were subjected to a roughness test before dipping in handing agents, then divided into three groups according to the type of wax in which they were dipped. (10 specimens for each type). Surface roughness test was done by a profilometer where three readings were taken for all the specimens' surfaces randomly. The mean was then extracted for the roughness values before and after dipping in waxes.                                                                                                                                                 Results: the mean and standard deviation were tabulated and statistically analyzed using students T- test. The roughness values were decreased after the specimens were dipped in waxes (P value < 0.001 HS highly significant). Conclusion: The dipping process with hardening agents has significantly improved the surface roughness of the specimens' investment materials.

scholarly journals Colour Stability of Veneering Composites after Accelerated Aging

2010 ◽  
Vol 04 (02) ◽  
pp. 137-142 ◽  
Author(s):  
Triantafillos Papadopoulos ◽  
Aspasia Sarafianou ◽  
Andreas Hatzikyriakos
Keyword(s):  
Colour Change ◽  
Accelerated Aging ◽  
Blue Shift ◽  
Colour Stability ◽  
Before And After ◽  
Indirect Composites ◽  
Colour Changes ◽  
Indirect Composite ◽  
The Mean ◽  
One Way Anova

Objectives: To investigate the colour stability of four indirect composite restorative materials after accelerated aging.Methods: Four indirect composites (Gradia, Signum+, HFO and Adoro) were used. For each material, six specimens were prepared and subjected to accelerated aging (Suntest CPS+, Atlas, Chicago, IL, USA) according to ISO 7491. A Dr. Lange Microcolor Data Station colorimeter (Braive Instruments, Liege, Belgium) was used to measure specimen colour before and after aging. Measurements were performed according to the CIE L*a*b* system, and the mean L*, a* and b* values for each material were calculated. The equation ΔΕ = [(ΔL*)2 + (Δa*)2 + (Δb*)2]1/2 was used to measure the total colour change (ΔΕ), where ΔL*, Δa* and Δb* are the differences in the respective values before and after aging. One-way ANOVA were used to determine statistically significant differences in ΔL*, Δa*, Δb* and ΔΕ.Results: No statistically significant differences were found in ΔL*, Δa*, Δb* and ΔΕ among the materials tested (PΔL*=.063; PΔa*=.521; PΔb*=.984 and PΔE=.408). After aging, Gradia specimens showed an increase in lightness (ΔL*=0.36) and a green-yellow shift (Δa*=-1.18, Δb*=0.6), while Signum+ specimens exhibited an increase in lightness (ΔL*=0.5) and a green-blue shift (Δa*=-0.9, Δb*=- 0.45). HFO specimens exhibited an increase in lightness (ΔL*=0.75) and a green-yellow shift (Δa*=- 1.3, Δb*=0.06), and Adoro specimens exhibited an increase in lightness (ΔL*=2.07) and a green-yellow shift (Δa*=-1.3, Δb*=0.68).Conclusions: Colour changes were found to be within accepted values of perceptibility and clinical acceptance after accelerated aging, and no statistically significant differences were found in ΔL*, Δa*, Δb* and ΔΕ among the materials tested. (Eur J Dent 2010;4:137-142)

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