Memory stabilities and mechanisms of organic bistable devices with a phase-separated poly(methylmethacrylate)/poly(3-hexylthiophene) hybrid layer

2012 ◽  
Vol 13 (11) ◽  
pp. 2485-2488 ◽  
Author(s):  
Woo Seung Song ◽  
Hee Yeon Yang ◽  
Chan Ho Yoo ◽  
Dong Yeol Yun ◽  
Tae Whan Kim
Author(s):  
Jorge Perdigao

In 1955, Buonocore introduced the etching of enamel with phosphoric acid. Bonding to enamel was created by mechanical interlocking of resin tags with enamel prisms. Enamel is an inert tissue whose main component is hydroxyapatite (98% by weight). Conversely, dentin is a wet living tissue crossed by tubules containing cellular extensions of the dental pulp. Dentin consists of 18% of organic material, primarily collagen. Several generations of dentin bonding systems (DBS) have been studied in the last 20 years. The dentin bond strengths associated with these DBS have been constantly lower than the enamel bond strengths. Recently, a new generation of DBS has been described. They are applied in three steps: an acid agent on enamel and dentin (total etch technique), two mixed primers and a bonding agent based on a methacrylate resin. They are supposed to bond composite resin to wet dentin through dentin organic component, forming a peculiar blended structure that is part tooth and part resin: the hybrid layer.


2019 ◽  
Vol 70 (7) ◽  
pp. 2608-2613
Author(s):  
Larisa Simona Deac ◽  
Kamel Earar ◽  
Adela Loredana Colceriu Burtea ◽  
Alexandra Stefania Berghe ◽  
Aurora Antoniac ◽  
...  

This study evaluates and compares by dye penetration method and SEM photomicrographs the sealing obtained using two different classes of adhesive systems (etch-and-rinse and self-etch with selective etching) with SDR (Dentsply) bulk fill composite. 84 class V cavities were prepared on oral and vestibular face of 42 intact, freshly extracted wisdom teeth. The cavities were randomly divided in two groups and restored: Group 1 with prime &bond one select (Dentsply) and SDR (Dentsply) and Group 2 with prime&bond one Etch&Rinse (Dentsply) and SDR (Dentsply). Prime&bond one Select (Dentsply) is a single component adhesive and can be used in self etch mode, in selective enamel etch mode, or in etch-and-rinse mode. We chosen for this study the selective etch of the enamel mode. Prime&bond one Etch Rinse (Dentsply) is a universal etch-and-rinse one-bottle dental adhesive, designed to be used in two steps. The bulk fill composites are commonly used in modern dentistry due to their properties of low polymerization shrinkage and curing in layer of 4 mm depth, offering the practitioner a fast clinical procedure with good results. The results showed a good sealing at enamel and dentin margins with no statistically significant difference between adhesives, even though the mean of enamel infiltration was smaller for Group1. Furthermore the results show that there were differences between the two groups, for the infiltrations at the enamel, the values of microleakage being arithmetically higher for Group 1, but with no statistically difference between the two groups.SEM images showed for both groups a good adhesion surface with the tooth, but the hybrid layer of the total-etch adhesives is different from the hybrid layer formed by self etch adhesives, in terms of thickness, uniformity. In conclusion both adhesive systems have equivalent sealing qualities and can be successfully used with SDR.


2021 ◽  
Vol 5 ◽  
pp. 100111
Author(s):  
Louis Van der Meeren ◽  
Joost Verduijn ◽  
Jie Li ◽  
Ellen Verwee ◽  
Dmitri V. Krysko ◽  
...  

2021 ◽  
pp. 100266
Author(s):  
Pavel Seredin ◽  
Dmitry Goloshchapov ◽  
Vladimir Kashkarov ◽  
YuYu Khudyakov ◽  
Ivan Ippolitov ◽  
...  

Author(s):  
Taíse Alessandra Hanzen ◽  
Mario Felipe Gutiérrez ◽  
Thalita de Paris Matos ◽  
Alexandra Mara de Paula ◽  
Fabiana Suelen Figueredo de Siqueira ◽  
...  

2021 ◽  
pp. 132789
Author(s):  
Wen-Tse Huang ◽  
Yedukondalu Meesala ◽  
Hsi-Ping Hsueh ◽  
Mu-Huai Fang ◽  
Zhen Bao ◽  
...  

2011 ◽  
Vol 1 (2) ◽  
Author(s):  
Jerzy Smolik

AbstractThis article presents results which enabled the determination of the role of CrN coating and the influence of its thickness on the effectiveness of hybrid layer “nitrided layer / CrN coating” in the process of increasing the durability of forging dies. Dies coated with hybrid layers “nitrided layer / CrN coating” with various CrN coating thickness were — after different maintenance periods — subjected to metallographic testing, 3D shape testing and SEM analysis. Hardness distribution was also determined. The obtained results revealed that for all tested dies, independently from CrN coating thickness, the main mechanisms of their destruction was mechanical and thermal fatigue, and plastic deformation. It has been shown that the main role of CrN coating in the hybrid layer ”nitrided layer / PVD coating” is to counteract a high temperature influence the source of which is forging on die material. In order to do so the CrN coating should be characterized by a considerably lower thermal conductivity coefficient to steel and low hardness so that it can efficiently resist fatigue processes in the forging process. Based on testing conducted by means of the sin 2 φ method, it was revealed that internal stresses are vitally important for CrN coating for fatigue resistance of hybrid layer ”nitrided layer / CrN coating” during the forging process.


2017 ◽  
Vol 41 (1) ◽  
pp. 53-61 ◽  
Author(s):  
Marwa Abdel Hafez ◽  
Mona Elkateb ◽  
Sonia El Shabrawy ◽  
Amel Mahmoud ◽  
Omar El Meligy

Aim: To evaluate the microleakage of composite restorations following Papain-based chemo-mechanical caries removal compared to the conventional drilling method. The characteristic of the hybrid layer was also studied using scanning electron microscopy. Study design: The sample included thirty freshly extracted and exfoliated primary molars with open proximal carious dentin lesions. Teeth were divided into two equal groups, according to method of caries removal. Following caries removal, cavity preparations were restored with composite resin. After thermocycling, teeth were sealed apically and coated with nail polish except the surface of restorations and the surrounding 1mm. Teeth were immersed in basic fuschin dye solution, then they were sectioned mesiodistally. The extent of dye penetration was detected using a light stereomicroscope. After microleakage test, the resin/dentin interface was examined using scanning electron microscopy. Results: There was no significant difference in the degree of leakage between both groups. In the Papacarie group, longer and numerous resin tags were observed with statistically significant thicker hybrid layer than those following the drilling method. However, there was no significant difference between the diameters of resin tags of both groups. Conclusions: Papacarie does not adversely affect the microleakage of composite restorations and provides a suitable surface for bonding.


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