Search results for "amalgam"
showing 10 items of 38 documents
Sealing ability of five different retrograde filling materials.
1996
The sealing ability of Amalgam, Harvard-Cement, Diaket, gold-leaf, and Ketac-Endo as retrofilling materials was investigated. Paper cones were fixed with Harvard-Cement in the instrumented roots of 100 extracted human incisors. Apicectomy was performed and a 2-mm-deep retrograde cavity was prepared. Teeth were assigned to five groups (n = 20); each group received a different filling material. Surfaces of the roots were isolated with nail polish. Teeth, were stored in 1% methylene blue dye for 72 h. Roots were sectioned, and the depth of dye penetration was evaluated through a stereomicroscope. Retrofills with Ketac-Endo showed significantly less leakage compared with amalgam. There was no s…
Comparison of different uncertainty techniques in urban stormwater quantity and quality modelling
2011
Abstract Urban drainage models are important tools used by both practitioners and scientists in the field of stormwater management. These models are often conceptual and usually require calibration using local datasets. The quantification of the uncertainty associated with the models is a must, although it is rarely practiced. The International Working Group on Data and Models, which works under the IWA/IAHR Joint Committee on Urban Drainage, has been working on the development of a framework for defining and assessing uncertainties in the field of urban drainage modelling. A part of that work is the assessment and comparison of different techniques generally used in the uncertainty assessm…
Territorial fragmentation in post-communist Romania: the not so curious case of a de-amalgamation reform
2021
Abstract The efficiency-driven trend towards amalgamation characterising local government reforms in Europe seems to have escaped Romania, which displays a significant increase in the number of local governments post-1989. This is the result of rural first-tier local governments splitting into smaller units. The paper examines objective factors and subjective motivations that have shaped the behaviour of both national and local actors in dealing with territorial reform. First, it explores the rationale and rationality of a central government initiative to facilitate municipal splits against a set of criteria derived from the literature. Second, it examines the municipal splits occurring bet…
Studien zum Vorgang der Wasserstoffübertragung, 67. Endioldiester durch acylierende elektroreduktive Dimerisierung von Carbonsäurechloriden mit Lithi…
1983
Aromatische, aliphatische und aromatisch-aliphatische Carbonsaurechloride (und Anhydride) werden mit Lithiumamalgam (Li/Hg) durch acylierende reduktive Dimerisierung in wechselnden Ausbeuten (meist 70%) in cis- und/oder trans-Endioldiester 1–10 ubergefuhrt. Der Einflus des Losungsmittels auf den Reaktionsverlauf wird untersucht. Aus 2,2′-Diphensauredichlorid entsteht das Phenanthrenderivat 7, aus Phthaloyldichlorid Phthalid 8. Li/Hg wandelt Diphenyl-phosphinylchlorid in Tetraphenyldiphosphandioxid (15) um. Auf die Bestimmung der Halbstufenpotentiale von 12 Saurechloriden und vier 1,2-Diketonen grundet sich die Formulierung des Reaktionsmechanismus. 1,2-Diketone sind Zwischenprodukte der acy…
Un condiscípulo español de Alexander von Humboldt en la Bergakademie de Freiberg: Josef Ricarte y su informe sobre el método de amalgamación de Born …
2004
[ES] Se estudia la labor de Joseph Ricarte, pensionado en París y luego en Centroeuropa, para estudiar el método de amalgamación de Born. El trabajo de Ricarte fue especialmente interesante en la Escuela de minas de Schemnitz, a cargo del profesor Antón Ruprecht, en 1787, aunque también se exponen los viajes de aprendizaje con Andrés Manuel del Río por diversas regiones centroeuropeas (Alta y baja Hungría, Austria, Bohemia,etc...) hasta su llegada a Freiberg, en Sajonia, donde estudiaron con A. Werner y fueron compañeros de Alexander von Humboldt. Acompaña al artículo una disertación de Ricarte sobre las mejoras introducidas por Ruprecht al método del barón de Born.
Lexical classes and constructions: an analysis of the constructional realization of entity-specific change-of-state English verbs
2013
This study analyzes a so far neglected part of the constructional behavior of Levin's (1993) entity-specific change-of-state verbs. More specifically, we discuss the integration of verbs from this lexical class into the intransitive-resultative construction. We base our analysis on the Lexical Constructional Model or LCM (Ruiz de Mendoza and Mairal 2008, 2011; Mairal and Ruiz de Mendoza 2009; Ruiz de Mendoza 2013). It will be shown that the internal and external constraints postulated by the LCM constitute useful explanatory and analytical tools for the fusion processes between these verbs and the intransitive-resultative construction. We also propose a classification of these verbs on the …
Clinicopathological and Immunohistochemical Study of Oral Amalgam Pigmentation
2012
Amalgam tattoo, the most common exogenous oral pigmentation, can sometimes be confused with melanotic lesions, being then biopsied. We present the clinicopathological characteristics of 6 biopsied cases (5 females and 1 male) of oral amalgam pigmentation. The most common location was the gingival mucosa, followed by the buccal and palatal mucosa. Morphology and distribution (stromal, perivascular, perineural, endomysial) of pigmentation was variable; there was only 1 case with fibrous capsular reaction and likewise only a single case of granulomatous foreign body reaction. Morphological variability is conditioned by the timing and amount of the pigment deposit, which is often associated wit…
Amalgam fillings and cognitive abilities in a representative sample of the elderly population.
2000
Objectives: The ongoing controversial discussion about a possible negative effect of amalgam fillings on the cognitive abilities and the pathogenesis dementia was the objective of the present study. Sample: A total of 300 patients aged from 70 to 103 years were selected from the multidisciplinary ‘Berlin Aging Study’ (Base). The sample was heterogeneous concerning lifestyle, education and social prestige. According to their dental state subjects were allocated into three groups: edentate ≥20 years (I) and residual teeth without (II) or with (III) amalgam restorations. All groups were matched for age and gender. Design: Dental examinations and various psychiatric as well as psychological ass…
Traditional endodontic surgery versus modern technique: a 5-year controlled clinical trial.
2014
In this study, we compared outcomes of traditional apicoectomy versus modern apicoectomy, by means of a controlled clinical trial with a 5-year follow-up. The study investigated 938 teeth in 843 patients. On the basis of the procedure performed, the teeth were grouped in 3 groups. Differences between the groups were the method of osteotomy (type of instruments used), type of preparation of retrograde cavity (different apicoectomy angles and instruments used for root-end preparation), and root-end filling material used (gray mineral trioxide aggregate or silver amalgam). Outcome (tooth healing) was estimated after 1 and 5 years, postoperatively. Clinical success rates after 1 year were 67% (…
Effect of apical root-end filling materials on gingival fibroblasts
2003
AIM To determine the influence of root-end filling materials on specific cellular responses of gingival fibroblasts (GF). METHODOLOGY The reactions of cells in contact with mineral trioxide aggregate (MTA), amalgam and a chemically inert titanium alloy were determined based on the assessment of prostaglandin (PGE2) release with and without arachidonic acid stimulation, protein and lactate synthesis, and cell proliferation. Cells cultured without test materials served as controls (100%). RESULTS The fibroblasts showed a highly significant decrease in protein synthesis when in contact with amalgam (61.8 +/- 13.6%); MTA (91.2 +/- 5.9%) and titanium (92.4 +/- 4.7%) had little effect on this par…