scholarly journals Effect of Different Photoiniciers of Experimental Adhesive Systems on Adhesive Interface Union Resistance

10.3823/2567 ◽  
2018 ◽  
Vol 11 ◽  
Author(s):  
Tiago Norões Gomes ◽  
Jefferson David Melo de Matos ◽  
John Eversong Lucena de Vasconcelos ◽  
Karina Andrea Novaes Olivieri ◽  
William Cunha Brandt ◽  
...  
Keyword(s):  
Organic Matrix ◽  
Bending Test ◽  
Curing Time ◽  
Conventional System ◽  
Adhesive Systems ◽  
Tukey Test ◽  
Curing Light ◽  
Conventional Systems ◽  
Flexural Resistance ◽  
Triethyleneglycol Dimethacrylate

Aim: The objective of this study was to investigate the performance of experimental resinous adhesives containing different combinations of photoinitiators systems through the bending test. Material and Methods: Resinous adhesive formulations were prepared with monomer mixtures consisting of 50% by mass of bisphenol dimethacrylate glycidyl (BisGMA) and 50% by mass of triethyleneglycol dimethacrylate (TEGDMA). The photoinitiators were used, camphorquinone (CQ) and bis-alkyl phosphinic oxide (BAPO). The co-initiators were diphenyliodonium hexafluorophosphate (DFI) and the amine (dimethylamino methylmethacrylate - DMAEMA) in the 1:1 proportion by mass. The photopolymerizable initiator systems were dissolved in the organic matrix at 0.5% by mass concentrations, creating eight groups (G1- CQ, G2- CQ/amine, G3- CQ/DFI, G4- CQ/amine/DFI, G5- BAPO, G6- BAPO/amine, G7- BAPO/DFI, G8- BAPO/amine/DFI). Samples with 7.0 mm in length, 2.0 mm wide and 1.0 mm height were prepared (n=12). The curing light used was VALO – Ultradent and the curing time was 20 s. The samples were subjected to evaluation of bending test at three points at a speed of 1 mm/min to evaluate the flexural resistance (FR). Results: The results were submitted to analysis of variance with one criterion (p < 0,001) and multiple comparisons were performed using Tukey test. Systems with the photoinitiator BAPO showed higher or equivalent bending values that demonstrated by the conventional system containing CQ/amine. Systems with the DFI had higher flexural values in relation to those demonstrated by systems without the DFI to CQ. Conclusion: The use of systems with alternative photoinitiators and co-initiators allows to obtain superior properties to the conventional system, making these promising systems to act both in isolation as associated with conventional systems.

scholarly journals Polymerization of a dual-cured cement through ceramic: LED curing light vs halogen lamp

2004 ◽  
Vol 12 (4) ◽  
pp. 312-316 ◽  
Author(s):  
Lawrence Gonzaga Lopes ◽  
Eduardo Batista Franco ◽  
Abrão Name Neto ◽  
Francyle S. Herrera ◽  
Cristina Kurachi ◽  
...  
Keyword(s):  
Vickers Hardness ◽  
Halogen Lamp ◽  
Steel Matrix ◽  
Curing Time ◽  
Control Groups ◽  
Tukey Test ◽  
Ceramic Disc ◽  
Light Curing ◽  
Curing Light ◽  
And Control

The aim of this study was to investigate the influence of light source, LED unit and halogen lamp (HL), on the effectiveness of Enforce dual-cured cement cured under a ceramic disc. Three exposure times (60, 80 and 120 s) were also evaluated. Two experimental groups, in which the polymerization of the dual-cured cement was performed through a ceramic disc, and two control groups, in which the polymerization of the dual-cured cement was performed directly without presence of ceramic disc were subdivided into three subgroups (three different exposure times), with five specimens each: G1A- HL 60s; G1B- HL 80s; G1C- HL 120s; G2A- LED 60s; G2B- LED 80s; G2C- LED 120s; and control groups: G3A- HL 60s; G3B- HL 80s; G3C- HL 120s; G4A- LED 60s; G4B- LED 80s and G4C- LED 120s. Cement was applied in a steel matrix (4mm diameter, 1.2mm thickness). In the experimental groups, a ceramic disc was placed on top. The cement was light-cured through the ceramic by a HL and LED, however, the control groups were cured without the ceramic disc. The specimens were stored in a light-proof container at 37ºC for 24 hours, then Vickers hardness was determined. A four-way ANOVA and Tukey test (p£ 0.05) were performed. All specimens cured by LED for 60s showed inferior values compared with the halogen groups. In general, light-curing by LED for 80s and 120s was comparable to halogen groups (60s and 80s) and their control groups. LED technology can be viable for light-curing through conventional ceramic indirect restorations, when curing time is increased in relation to HL curing time.

scholarly journals Progress of soybean charcoal rot under tillage and no-tillage systems in Brazil

2003 ◽  
Vol 28 (2) ◽  
pp. 131-135 ◽  
Author(s):  
Álvaro M. R. Almeida ◽  
Lilian Amorim ◽  
Armando Bergamin Filho ◽  
Eleno Torres ◽  
José R. B. Farias ◽  
...  
Keyword(s):  
Cropping Systems ◽  
Disease Incidence ◽  
Cropping System ◽  
Macrophomina Phaseolina ◽  
Conventional System ◽  
Survival Times ◽  
Charcoal Rot ◽  
No Till ◽  
Four Seasons ◽  
Conventional Systems

The increase in incidence of charcoal rot caused by Macrophomina phaseolina on soybeans (Glycine max) was followed four seasons in conventional and no-till cropping systems. In the 1997/98 and 2000/01 seasons, total precipitation between sowing and harvest reached 876.3 and 846.9 mm, respectively. For these seasons, disease incidence did not differ significantly between the no-till and conventional systems. In 1998/99 and 1999/00 precipitation totaled 689.9 and 478.3 mm, respectively. In 1998/99, in the no-till system, the disease incidence was 43.7% and 53.1% in the conventional system. In 1999/00 the final incidence was 68.7% and 81.2% for the no-till and conventional systems, respectively. For these two seasons, precipitation was lower than that required for soybean crops (840 mm), and the averages of disease incidence were significantly higher in the conventional system. The concentration of microsclerotia in soil samples was higher in samples collected in conventional system at 0 - 10 cm depth. However, analysis of microsclerotia in roots showed that in years with adequate rain no difference was detected. In dry years, however, roots from plants developed under the conventional system had significantly more microsclerotia. Because of the wide host range of M. phaseolina and the long survival times of the microsclerotia, crop rotation would probably have little benefit in reducing charcoal rot. Under these study conditions it may be a better alternative to suppress charcoal rot by using the no-till cropping system to conserve soil moisture and reduce disease progress.

scholarly journals Postharvest quality of strawberry fruits produced in organic and conventional systems

2011 ◽  
Vol 29 (4) ◽  
pp. 577-583 ◽  
Author(s):  
Letícia KP Camargo ◽  
Juliano Tadeu V de Resende ◽  
Tânia T Tominaga ◽  
Sonia Maria Kurchaidt ◽  
Cristhiano K Camargo ◽  
...  
Keyword(s):  
Titratable Acidity ◽  
Physicochemical Characteristics ◽  
Soluble Solids ◽  
Postharvest Quality ◽  
Conventional System ◽  
Organic System ◽  
Camino Real ◽  
Sensorial Attributes ◽  
Solids Content ◽  
Conventional Systems

The aim of this study was to determine some physicochemical characteristics of fruits of eight strawberry cultivars (Aromas, Camino Real, Campinas, Dover, Oso Grande, Toyonoka, Tudla-Milsei and Ventana) cultivated in organic and conventional systems. The evaluated characteristics were soluble solids (SS), titratable acidity (TA), SS/AT ratio and anthocyanins. Evaluated sensory characteristics were flavor and appearance. The cultivars had a differential performance between themselves and among the systems for the evaluated characteristics. Generally, the conventional system produced fruit with higher levels of soluble solids and, organic system produced higher concentrations of anthocyanins. The fruits of the cultivar Toyonoka had the best soluble solids content in both systems and the anthocyanins content of 'Tudla-Milsei' and 'Camino Real' were proeminent in comparison to the other cultivars. The fruits from the organic system of production were preferred by judges on the sensorial attributes. The highest notes were given to the appearance of the cultivar Ventana in the conventional system and 'Tudla-Milsei' in the organic system.

scholarly journals Benthic macroinvertebrates and degradation of phytomass as indicators of ecosystem functions in flooded rice cropping

2017 ◽  
Vol 52 (4) ◽  
pp. 261-270 ◽  
Author(s):  
Lilian Terezinha Winckler ◽  
Angélica Konradt Güths ◽  
Pâmela Rodrigues Gayer
Keyword(s):  
Benthic Macroinvertebrates ◽  
Trophic Group ◽  
Ecosystem Functions ◽  
Conventional System ◽  
Natural Wetland ◽  
Wetland Area ◽  
Organic System ◽  
Flooded Rice ◽  
Rice Area ◽  
Conventional Systems

Abstract: The objective of this work was to evaluate the ecosystem functions of a natural wetland and of artificially flooded rice areas, managed under organic and conventional systems, by phytomass degradation and by the colonization of this material by benthic macroinvertebrates. The experiment was carried out in a natural wetland area, and in two flooded rice areas managed under organic and conventional systems. Twenty-five decomposition bags filled with 10 g of dry vegetation were installed in each site. At 14, 28, 42, 56, and 70 days after the beginning of the experiment, five bags from each site were collected. Macroinvertebrates were identified and classified by functional trophic group. The number of species of benthic macroinvertebrates increased: natural wetland > organic system > conventional system. The Chironomidae group was present in all areas, confirming its food plasticity and adaptability to different substrates and environmental stress situations. The Amphipoda group was present only in the artificially flooded rice area, and the Acari, only in the natural wetland. The diversity of species in the natural wetland area was higher than in the artificially flooded rice area. Nutrient cycling, provided by phytomass decomposition, is affected by the management system, and the delay in this process causes a reduction of the ecosystem functions in the conventional system.

scholarly journals IDENTIFIKASI PENGARUH PENGGUNAAN RAIL CLIMBING SYSTEM PADA PEKERJAAN KONSTRUKSI COREWALL

2019 ◽  
Vol 7 (2) ◽  
Author(s):  
Redaksi Tim Jurnal
Keyword(s):  
Conventional System ◽  
Work Effectiveness ◽  
Structural Work ◽  
Work Duration ◽  
Two Systems ◽  
Conventional Systems ◽  
Over Time

In structural work, especially corewall, the use of conventional formwork systems decreases work effectiveness over time. PT. Total Bangun Persada, one of the stakeholders that applies innovation to increase the effectiveness of that is by using the rail climbing system as a solution to the problems faced. This study will compare the time effectiveness of conventional systems using corewall using the rail climbing system which was analyzed using cyclone to obtain effective repeat cycles. From the two systems, the results show that the corewall work using the rail climbing system is more effective with a work duration of 78 days compared to conventional system formwork with 84 days of work duration.

scholarly journals Soil fertility and crop yields in long-term organic and conventional cropping systems in Eastern Nebraska

2011 ◽  
Vol 27 (3) ◽  
pp. 200-216 ◽  
Author(s):  
Sam E. Wortman ◽  
Tomie D. Galusha ◽  
Stephen C. Mason ◽  
Charles A. Francis
Keyword(s):  
Soil Fertility ◽  
Crop Yields ◽  
Cropping Systems ◽  
Animal Manure ◽  
Conventional System ◽  
Organic System ◽  
Organic Systems ◽  
Long Term Study ◽  
Conventional Systems

AbstractOrganic agriculture aims to build soil quality and provide long-term benefits to people and the environment; however, organic practices may reduce crop yields. This long-term study near Mead, NE was conducted to determine differences in soil fertility and crop yields among conventional and organic cropping systems between 1996 and 2007. The conventional system (CR) consisted of corn (Zea maysL.) or sorghum (Sorghum bicolor(L.) Moench)–soybean (Glycine max(L.) Merr.)–sorghum or corn–soybean, whereas the diversified conventional system (DIR) consisted of corn or sorghum–sorghum or corn–soybean–winter wheat (wheat,Triticum aestivumL.). The animal manure-based organic system (OAM) consisted of soybean–corn or sorghum–soybean–wheat, while the forage-based organic system (OFG) consisted of alfalfa (Medicago sativaL.)–alfalfa–corn or sorghum–wheat. Averaged across sampling years, soil organic matter content (OMC), P, pH, Ca, K, Mg and Zn in the top 15 cm of soil were greatest in the OAM system. However, by 2008 OMC was not different between the two organic systems despite almost two times greater carbon inputs in the OAM system. Corn, sorghum and soybean average annual yields were greatest in either of the two conventional systems (7.65, 6.36 and 2.60 Mg ha−1, respectively), whereas wheat yields were greatest in the OAM system (3.07 Mg ha−1). Relative to the mean of the conventional systems, corn yields were reduced by 13 and 33% in the OAM and OFG systems, respectively. Similarly, sorghum yields in the OAM and OFG systems were reduced by 16 and 27%, respectively. Soybean yields were 20% greater in the conventional systems compared with the OAM system. However, wheat yields were 10% greater in the OAM system compared with the conventional DIR system and 23% greater than yield in the OFG system. Alfalfa in the OFG system yielded an average of 7.41 Mg ha−1annually. Competitive yields of organic wheat and alfalfa along with the soil fertility benefits associated with animal manure and perennial forage suggest that aspects of the two organic systems be combined to maximize the productivity and sustainability of organic cropping systems.

scholarly journals Impact of Solvent Evaporation and Curing Protocol on Degree of Conversion of Etch-and-Rinse and Multimode Adhesives Systems

2019 ◽  
Vol 2019 ◽  
pp. 1-6 ◽  
Author(s):  
Ceci Nunes Carvalho ◽  
Marcos Daniel Septímio Lanza ◽  
Letícia Gomes Dourado ◽  
Edilausson Moreno Carvalho ◽  
José Bauer
Keyword(s):  
Solvent Evaporation ◽  
Degree Of Conversion ◽  
Curing Time ◽  
Light Activation ◽  
Adhesive Systems ◽  
Air Drying ◽  
Air Stream ◽  
Etch And Rinse ◽  
Light Curing ◽  
One Step

Objectives. This study evaluated the effect of air-drying time and light-curing time on the degree of conversion (DC) of three etch-and-rinse adhesive systems: ONE-STEP (OS) and ONE-STEP plus (OSP), Ambar (AMB), and two multimode adhesive systems: All-Bond Universal (ABU) and ScotchBond Universal (SBU) by Fourier transform infrared (FTIR) analysis. Materials and Methods. The DC of each adhesive system was analyzed with six experimental different protocols: (1) immediate light curing for 10 s without solvent volatilization; (2) 10 s solvent volatilization with air stream plus 10 s light curing; (3) 60 s solvent volatilization with air stream plus 10 s light curing; (4) immediate light curing for 20 s without solvent volatilization; (5) 10 s solvent volatilization with air stream plus 20 s light curing; and (6) 60 s solvent volatilization with air stream plus 20 s light curing. FTIR spectra were obtained, and the DC was calculated by comparing the ratio of aliphatic/aromatic double carbon bonds before and after light activation (Bluephase 20i). The DC means were analyzed by three-way analysis of variance (ANOVA) and post hoc Tukey tests (α = 0.05). Results. Three-way ANOVA showed statistically significant adhesive, air-drying, and light-cured time (p<0.001). In general, there was a trend of increased DC when the adhesives were dried and cured for longer times, but that was not observed for all the adhesives tested. The acetone-based adhesive systems require an air-drying prior to light activation. The light-curing time of 20 s increases the DC of all materials tested. Conclusion. The results suggested that the DC of the adhesive systems tested was material dependent. In general, the protocol with solvent evaporation for 10 seconds with air syringe plus 20 seconds of light curing finds the high values of DC.

An economic comparison of conventional and reduced-chemical farming systems in Iowa

1991 ◽  
Vol 6 (4) ◽  
pp. 168-173 ◽  
Author(s):  
Craig Chase ◽  
Michael Duffy
Keyword(s):  
Cropping Systems ◽  
Farming Systems ◽  
Production Costs ◽  
Chemical System ◽  
Corn Yield ◽  
Conventional System ◽  
Economic Returns ◽  
Average Return ◽  
Labor Requirements ◽  
Conventional Systems

AbstractLabor requirements, production costs, yields, and economic returns were evaluated for conventional and reduced-chemical cropping systems in northeast Iowa from 1978 to 1989. Continuous corn (C-C) and corn-soybean (C-Sb) rotations represented the conventional system; a corn-oat-meadow (C-O-M) rotation represented the reducedchemical system. The C-C and C-Sb rotations used both commercial pesticides and fertilizers. The C-O-M rotation used manure for fertilization and applied pesticides only in emergencies. Operations for all systems were implemented by one farm manager. The C-Sb rotation had the highest corn yield over the 12-year period, and the C-O-M rotation the lowest. The corn within the C-O-M rotation, however, produced the second highest average return to land, labor, and management. With costs of production substantially lower than the conventional systems, the C-O-M corn crop had competitive returns despite lower yield. The C-Sb average return to land, labor, and management was significantly higher than for the other systems. Hourly labor charges of $4, $10, $20, and $50 had little effect on the rankings of economic returns. Because of unusually high alfalfa reseeding costs and low average oat yields, returns to the C-O-M rotation were significantly lower than C-Sb but comparable to C-C. With better alfalfa establishment and higher average oat yields, the reduced-chemical system might have been competitive with the C-Sb conventional system.

scholarly journals Microleakage Evaluation of Core Buildup Composite Resins with Total-Etch and Self-Etch Adhesive Systems

2010 ◽  
Vol 11 (2) ◽  
pp. 9-16
Author(s):  
Horieh Moosavi ◽  
Saied Mostafa Moazzami ◽  
Shaghayegh Loh ◽  
Soheil Salari
Keyword(s):  
Composite Resins ◽  
Adhesive Systems ◽  
Root Canal Therapy ◽  
Endodontically Treated Teeth ◽  
Dental Adhesive ◽  
Tukey Test ◽  
Dye Penetration ◽  
Self Etch ◽  
Nail Varnish ◽  
Better Than

Abstract Aim Core buildup composite resins with prefabricated posts are commonly used to restore endodontically treated teeth. This study compared the sealing ability of Core Max II and Panavia F2.0 cement with total-etch and self-etch adhesive systems. Methods and Materials Sixty recently extracted human second premolar teeth were chosen and their crowns were cut 3 mm above the CEJ. After preparing proximal boxes (4±1 mm buccolingually and 3 mm occlusogingivally dimensions) and finishing root canal therapy, the teeth were randomly divided into four groups (n=15): groups 1 and 2, Core Max II without and with total-etch adhesive; groups 3 and 4, Clearfil photocore composite, A2 shade, and Panavia F2.0 cement without and with self-etch adhesive respectively. The Dentatus posts (# 2 Long) were used in canals approximately 8 mm depth. According to manufacturer guidelines, pins were cemented and cores were restored. After keeping the specimens for 24 hours at 37°C and 100% humidity, they were thermally cycled for 500 cycles, sealed with nail varnish except 1 mm beyond the margins of restoration, and then immersed in a 0.5% fuschin basic for 24 hours. Samples were embedded in clear epoxy resin, sectioned mesiodistally, and observed at 20× magnification. The microleakage was assessed under stereomicroscope and the results were recorded in percentage of dye penetration to the whole path from the cavosurface margin of the proximal boxes to the end of the post. Analysis of variance and the Tukey test were used to evaluate the data (p=0.05). Results Groups 1 and 4 had the highest and the lowest values of microleakage respectively. Microleakage of Panavia F2.0 cement was lower than for Core Max II and for both cements using adhesive made the microleakage smaller than without it (p<0.05). Conclusion Application of adhesive using Core Max II cement and Panavia F2.0 cement is strongly recommended to decrease microleakage. Self-etch adhesive performed better than total-etch adhesive. Clinical Significance With regards to microleakage, the self-etching primer displayed better sealing than that obtained with the totaletching, two-step dental adhesive. Citation Moosavi H, Moazzami SM, Loh S, Salari S. Microleakage Evaluation of Core Buildup Composite Resins with Total-Etch and Self- Etch Adhesive Systems. J Contemp Dent Pract [Internet]. 2010 March; 11(2):009-016. Available from: http://www.thejcdp.com/journal/view/ volume11-issue2-moosavi.

scholarly journals Effect of Tooth-structure Thickness on Light Attenuation and Depth of Cure

2016 ◽  
Vol 41 (2) ◽  
pp. 200-207 ◽  
Author(s):  
NJ Hamlin ◽  
C Bailey ◽  
NC Motyka ◽  
KS Vandewalle
Keyword(s):  
Hybrid Composite ◽  
Light Attenuation ◽  
Depth Of Cure ◽  
Tooth Structure ◽  
Tukey Test ◽  
Group Data ◽  
Structure Thickness ◽  
Average Irradiance ◽  
Curing Light ◽  
Mandibular Third Molars

SUMMARY Newer bulk-fill composites claim a greater depth of cure than conventional resin-based composites. To facilitate complete curing, the manufacturer of SonicFill (Kerr) recommends curing from the occlusal, as well as the buccal and lingual, surfaces of the tooth. The purpose of this study was to quantify the degree of curing light attenuation as it passes through natural tooth structure, and how this attenuation affects the depth of cure of different posterior resin composites. Ten noncarious extracted mandibular third molars were sectioned to produce 5-mm-thick pieces of buccal tooth structure. Sanding 0.5-mm increments from the flattened surface produced 4.5-, 4.0-, 3.5-, 3.0-, 2.5-, 2.0-, and finally 1.5-mm-thick sections. A Bluephase G2 (Ivoclar) curing light with an 8-mm-diameter light guide set on high for 20 seconds was used for measurement of irradiance as it passed through different thicknesses of tooth structure and air. The average irradiance (mW/cm2) was measured with a MARC-RC Resin Calibrator with a 4-mm-diameter sensor (BlueLight Analytics). To measure depth of cure of a conventional hybrid composite (Herculite Ultra; Kerr) vs a bulk-fill hybrid composite (SonicFill) through varying thicknesses of tooth structure, composites were cured in a 4-mm-diameter × 10.25-mm-long split mold according to International Organization for Standardization 4049. A mean and standard deviation was determined per group. Data were analyzed with a one-way analysis of variance (ANOVA)/Tukey test and two-way ANOVA/Tukey test (α=0.05). One-way ANOVA/Tukey found a significant decrease in irradiance based on thickness of tooth structure or distance through air (p&lt;0.001). Two-way ANOVA/Tukey found a significant decrease in depth of cure based on thickness of tooth structure (p&lt;0.001) and on composite type (p&lt;0.001) with no significant interaction (p=0.623). SonicFill had a significantly greater depth of cure than Herculite Ultra.

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