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Thermosetting System (thermosetting + system)
Selected AbstractsThe anesthetic onset and duration of a new lidocaine/prilocaine gel intra-pocket anesthetic (Oraqix®) for periodontal scaling/root planingJOURNAL OF CLINICAL PERIODONTOLOGY, Issue 5 2001Johan Friskopp Abstract Background: A new non-injection anesthetic, lidocaine/prilocaine gel (Oraqix®, AstraZeneca) in a reversible thermosetting system, has been developed to provide local anesthesia for scaling/root planing (SRP). The aim of this study was to determine the anesthetic onset and duration of the gel for SRP in patients with periodontitis. Methods: 30 patients were randomized to either 30 s, 2 min, or 5 min of treatment with the gel prior to SRP of a tooth. The gel was applied to periodontal pockets with a blunt applicator. On completion of the SRP of each tooth (2,3 teeth treated/patient), the patients rated their pain on a 100-mm visual analogue scale (VAS). Results: The median VAS pain score was 7.5 mm in the 30-s group, 28.5 mm in the 2-min group, and 15.5 mm in the 5-min group, with a significant difference between the 30-s and 2-min groups (p=0.03). In 2 patients in the 5-min group, but none in the other groups, the SRP was interrupted due to pain. The mean duration of anesthesia measured as pain on probing were 18.1, 17.3, and 19.9 min in the 30-s, 2-min, and 5-min groups, respectively. There were no reports of numbness of the tongue, lip, or cheek, neither were there any adverse local reactions in the oral mucosa. The gel was easy to apply and did not interfere with the SRP procedure. Conclusion: Oraqix® provides anesthesia after an application time of 30 s, with a mean duration of action of about 17 to 20 min. Zusammenfassung Hintergrund: Eine neues nicht zu injizierendes Anästhetikum, Lidocain/Prilocain Gel (Oraqix®, Astra Zeneca) in einem reversiblen thermischen System, wurde entwickelt, um die lokale Anästhesie für die Wurzelreinigung und -glättung (SRP) zu verbessern. Das Ziel dieser Studie war die Bestimmung des Anästhesieeintrittes und der -dauer durch dieses Gel bei SRP bei Parodontitis-Patienten. Methoden: 30 Patienten wurden zufällig zur 30 Sekunden, 2 Minuten oder 5 Minuten Behandlung mit dem Gel vor der SRP eines Zahnes eingeteilt. Das Gel wurde mit einem stumpfen Applikator in die parodontalen Taschen appliziert. Nach der Vollendung der SRP eines jeden Zahnes (2,3 behandelte Zähne/Patient) beurteilten die Patienten ihre Schmerzen auf einer 100 mm visuellen Analogskala (VAS). Ergebnisse: Der mittlere VAS Score war 7.5 mm in der 30 Sekundengruppen, 28.5 mm in der 2 Minutengruppe und 15.5 mm in der 5 Minutengruppe mit einer signifikanten Differenz zwischen der 30 Sekunden und der 2 Minutengruppe (p=0.03). Bei 2 Patienten in der 5 Minutengruppe, aber keinem in einer anderen Gruppe, wurde das SRP wegen Schmerzen unterbrochen. Die mittlere Dauer der Anästhesie, gemessen als Schmerz auf Sondierung, war 18.1, 17.3 und 19.9 Minuten in der 30 Sekunden, 2 Minuten und 5 Minutengruppe. Es gab keine Berichte über eine Taubheit der Zunge, der Lippen oder der Wangen. Irgendwelche negativen lokalen Reaktionen an der Mukosa wurden nicht beobachtet. Das Gel war leicht zu applizieren und beeinflußte die SRP Prozedur nicht. Zusammenfassung: Oraqix® fördert die Anästhesie nach Applikation von 30 Sekunden mit einer mittleren Dauer von ungefähr 17 bis 20 Minuten. Résumé Un nouvel anesthésique non-injectable, un gel de lidocaine/prilocaine (Oraquix®, AstraZeneca) dans un système thermique réversible a été mis au point afin de créer une anesthésie locale lors du détartrage et du surfaçage radiculaire (SRP). Le but de cette étude a été de déterminer la prise et la durée anesthésique de ce gel pour le SRP chez des patients avec parodontite. 30 patients ont été traités avec ce gel pendant 30 s, 2 min ou 5 min avant le SRP d'une dent. Le gel a été placé dans les poches parodontales avec un applicateur arrondi. A la fin du SRP de chaque dent (2 à 3 dents traitées par patient) les patients ont quantifié leur douleur sur une échelle analogue visuelle de 100 mm (VAS). Le score de douleur VAS moyen était de 7.5 mm dans le groupe de 30 s, 28.5 mm dans le groupe 2 min et de 15.5 min dans celui de 5 min avec une différence significative entre les groupes 30 s et 2 min (p=0.03). Chez 2 patients du groupe 5 min mais chez aucun des 2 autres groupes le SRP a été interrompu à cause de la douleur. La durée moyenne d'anesthésie mesurée en tant que douleur au sondage était respectivement de 18.1, 17.3 et 19.9 min pour les groupes 30 s, 2 min et 5 min. Il n'y a eu aucune plainte d'anesthésie de la langue, des lèvres ou des joues ni aucune réaction locale négative de la muqueuse buccale. Le gel a été facilement appliqué et n'a absolument pas gêné le SRP. L'Oraquix® apporte une anesthésie après un temps d'application de 30 s avec une durée d'action de 17 à 20 min. [source] The electrical behavior of thermosetting polymer composites containing metal plated ceramic fillerPOLYMER COMPOSITES, Issue 1 2005Hedva Bar This paper describes the electrical behavior of a thermosetting system, based on epoxy resin, containing metal plated fillers. Ceramic fillers such as chopped glass fibers and mica flakes were coated with copper by electroless plating and incorporated into an epoxy resin based on di-glycidyl ether of bisphenol A (DGEBA) with tri-ethylenetetramine (TETA) curing agent. The percolation threshold in these systems is obtained at very low copper contents of 0.11,0.44 vol%. The epoxy/copper coated mica system is characterized by an extremely large positive temperature coefficient (PTC) effect, which is not followed by a negative temperature coefficient (NTC) effect. Increasing the copper coated mica concentration raises the PTC temperature of the first temperature cycle, and exposing the material to continuous heating-cooling cycles results in a decrease in the PTC temperature and an increase of its room temperature resistivity. Inverse relations were found between the coefficient of thermal expansion and the PTC temperature. Accordingly, the mechanism governing the PTC effect in the epoxy/copper coated mica composite is based on a larger thermal expansion coefficient of the matrix compared with the ceramic filler. POLYM. COMPOS., 26:12,19, 2005. © 2004 Society of Plastics Engineers. [source] Processability studies of silica-thermoset polymer matrix nanocompositesPOLYMER ENGINEERING & SCIENCE, Issue 2 2008C. Lekakou The aim of this study is to investigate the processability of silica-thermoset polymer matrix nanocomposites in terms of dispersion of silica nanoparticles and their effect on curing. Two thermosetting resins were considered, an epoxy and a polyester resin, with 5% silica, although 1% silica was also used in preliminary studies in the polyester system. Various combinations of mechanical mixing and sonication were investigated for the dispersion of silica nanoparticles under different processing conditions and times in solvent-free and solvent-containing systems. It was found that the best dispersion route involved a solvent-aided dispersion technique. Consequently, different procedures for the solvent removal were investigated. Optical microscopy and SEM were used to characterize the resulting nanocomposites. DSC and rheological DMTA tests demonstrated that the silica nanoparticles shorten the gel time and promote curing in these thermosetting systems. POLYM. ENG. SCI., 2008. © 2007 Society of Plastics Engineers [source] Thermally reversible materials based on thermosetting systems modified with polymer dispersed liquid crystals for optoelectronic application,POLYMERS FOR ADVANCED TECHNOLOGIES, Issue 11-12 2006A. Tercjak Abstract The main aim of this research was the generation of new intelligent materials, in this case thermoreversible material, based on an epoxy matrix modified with liquid crystal for optoelectronic application. The samples were prepared by the reaction-induced phase separation (RIPS) of a solution of 4,-(hexyloxy)-4-biphenyl-carbonitrile (HOBC) and polystyrene (PS) in diglicydylether of bisphenol-A epoxy resin (DGEBA). The systems were cured with a stoichiometric amount of an aromatic amine hardener, 4,4,-methylene bis(3-chloro-2,6-diethylaniline) (MCDEA). Taken into account results obtained by differential scanning calorimetry (DSC) and transmission optical microscopy (TOM) equipped with a hot stage it was found that depending on morphology generated by RIPS of HOBC/thermoplastic particles in the epoxy matrix thermally reversible light scattering (TRLS) material can be obtained. Copyright © 2006 John Wiley & Sons, Ltd. [source] | ||||||||||