A universal adhesive containing copper nanoparticles improves the stability of hybrid layer in a cariogenic oral environment: An in situ study

Author(s):  
Omar Vidal ◽  
Thalita de Paris Matos ◽  
Alejandra Núñez ◽  
Luján Méndez-Bauer ◽  
Elisama Sutil ◽  
...  
2006 ◽  
Vol 20 (2) ◽  
pp. 91-96 ◽  
Author(s):  
Mônica Tostes Amaral ◽  
Antônio Carlos Guedes-Pinto ◽  
Orlando Chevitarese

This work evaluated the remineralization of demineralized enamel of pits and fissures of human third molars sealed with a glass ionomer cement (Fuji IX, GC Corporation - Japan) or with a Bis-GMA sealant (Delton - Dentsply). Ten volunteers participated in this in situ study that consisted of two thirty-day periods using intra-oral devices, with a week’s interval in between. Four experimental treatment procedures and one control were randomly assigned to the volunteers’ specimens: Group I, no treatment, control; Group II, artificial caries process; Group III, same treatment as Group II, but sealed with Delton (Dentsply); Group IV, same treatment as Group II, but sealed with Fuji IX (GC Corporation - Japan); Group V, same treatment as Group II and no sealing. Groups I and II were not submitted to the oral environment and served as controls. After a period of 30 days in the oral environment, the specimens were removed from the devices, embedded in acrylic resin, ground flat and polished. Then, Knoop hardness tests were performed, with a 25 g static load applied for 15 seconds. The measurements were made from the base of the fissure up to an opening of 600 µm, pre-established between the inclines of the cusps. Three indentations were then made, located at 25, 75, and 125 µm in depth from the outer enamel margin and 100 µm apart from each other (Micromet 2003). The Brieger F and Bonferroni’s tests were applied to the measurements. It was concluded that sealing with the glass ionomer cement Fuji IX was capable of making the enamel of pits and fissures more resistant by increasing the value of Knoop hardness.


Polymers ◽  
2021 ◽  
Vol 13 (16) ◽  
pp. 2708
Author(s):  
Georgi Iliev ◽  
Louis Hardan ◽  
Cynthia Kassis ◽  
Rim Bourgi ◽  
Carlos Enrique Cuevas-Suárez ◽  
...  

This paper presents state of the art universal adhesive systems and the effect of shelf-life and storage conditions on their bond performance. Three topics are explored in this review: an introduction to the topic, the mechanisms responsible for the degradation of the hybrid layer, and the factors that play a role in the stability of universal adhesives. In addition, issues such as potential durability and clinical importance are discussed. Universal adhesive systems are promising but must be handled and stored according to the manufacturer’s instructions, with careful attention given to the details of shelf-life and storage conditions for maximal success. It appears that the components of universal adhesives play an important role in their stability. Furthermore, HEMA-free formulations using methacrylamides lead to longer shelf-life. Further research is needed to prove these hypotheses.


2016 ◽  
Vol 49 ◽  
pp. 60-67 ◽  
Author(s):  
Viviane Hass ◽  
Alexandra Mara de Paula ◽  
Sibelli Parreiras ◽  
Mário Felipe Gutiérrez ◽  
Issis Luque-Martinez ◽  
...  

Author(s):  
J. R. Reed ◽  
D. J. Michel ◽  
P. R. Howell

The Al6Li3Cu (T2) phase, which exhibits five-fold or icosahedral symmetry, forms through solid state precipitation in dilute Al-Li-Cu alloys. Recent studies have reported that the T2 phase transforms either during TEM examination of thin foils or following ion-milling of thin foil specimens. Related studies have shown that T2 phase transforms to a microcrystalline array of the TB phase and a dilute aluminum solid solution during in-situ heating in the TEM. The purpose of this paper is to report results from an investigation of the influence of ion-milling on the stability of the T2 phase in dilute Al-Li-Cu alloy.The 3-mm diameter TEM disc specimens were prepared from a specially melted Al-2.5%Li-2.5%Cu alloy produced by conventional procedures. The TEM specimens were solution heat treated 1 h at 550°C and aged 1000 h at 190°C in air to develop the microstructure. The disc specimens were electropolished to achieve electron transparency using a 20:80 (vol. percent) nitric acid: methanol solution at -60°C.


Sensors ◽  
2021 ◽  
Vol 21 (8) ◽  
pp. 2830
Author(s):  
Sili Wang ◽  
Mark P. Panning ◽  
Steven D. Vance ◽  
Wenzhan Song

Locating underground microseismic events is important for monitoring subsurface activity and understanding the planetary subsurface evolution. Due to bandwidth limitations, especially in applications involving planetarily-distributed sensor networks, networks should be designed to perform the localization algorithm in-situ, so that only the source location information needs to be sent out, not the raw data. In this paper, we propose a decentralized Gaussian beam time-reverse imaging (GB-TRI) algorithm that can be incorporated to the distributed sensors to detect and locate underground microseismic events with reduced usage of computational resources and communication bandwidth of the network. After the in-situ distributed computation, the final real-time location result is generated and delivered. We used a real-time simulation platform to test the performance of the system. We also evaluated the stability and accuracy of our proposed GB-TRI localization algorithm using extensive experiments and tests.


2021 ◽  
Vol 27 (S1) ◽  
pp. 1554-1555
Author(s):  
Chen Gu ◽  
Nabil Bassim ◽  
Hatem Zurob

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