fa Temperature-dependence of creep behaviour of dental resin-composites ترمیمی Cosmetic and Restorative Dentistry پژوهشي Research <p> <strong>Objectives </strong></p><p> To determine the effect of temperature, over a clinically relevant range, on the creep behaviour of a set of conventional and flowable resin-composites including two subgroups having the same resin matrix and varied filler loading. </p><p> <strong>Methods</strong></p><p>  Eight dental resin-composites: four flowable and four conventional were investigated. Stainless steel split moulds (4mm×6mm) were used to prepare cylindrical specimens for creep examination. Specimens were irradiated in the moulds in layers of 2mm thickness (40s each), as well as from the radial direction after removal from the moulds, using a light-curing unit with irradiance of 650mW/cm2. A total of 15 specimens from each material were prepared and divided into three groups (n=5) according to the temperature Group I: (23°C), Group II: (37°C) and Group III: (45°C). Each specimen was loaded (20MPa) for 2h and unloaded for 2h. Creep was measured continuously over the loading and unloading periods. </p><p> <strong>Results</strong></p><p>  At higher temperatures greater creep and permanent set were recorded. The lowest mean creep occurred with GS and GH resin-composites. Percentage of creep recovery decreased at higher temperatures. At 23°C, the materials exhibited comparable creep. At 37°C and 45°C, however, there was a greater variation between materials. For all resin-composites, there was a strong linear correlation with temperature for both creep and permanent set.</p><p> <strong> Conclusions</strong></p><p>  Creep parameters of resin-composites are sensitive to temperature increase from 23 to 45°C, as can occur intra-orally. For a given resin matrix, creep decreased with higher filler loading. </p><hr><p></p><p> <strong>Source: </strong>Journal of Dentistry</p><p><a href="http://www.jodjournal.com/article/S0300-5712(12)00320-X/abstract" target="_blank"><font color="#0000ff"> Full Text</font></a></p> Creep and recovery, Resin-composites, Temperature, Filler loading, Resin matrix 0 0 http://idai.ir/browse.php?a_code=A-10-32-2131&slc_lang=fa&sid=1 S. El-Safty 10031947532846009998 10031947532846009998 Yes School of Dentistry and Photon Science Institute, University of Manchester, UK N. Silikas 10031947532846009999 10031947532846009999 No School of Dentistry and Photon Science Institute, University of Manchester, UK D.C. Watts 100319475328460010000 100319475328460010000 No School of Dentistry and Photon Science Institute, University of Manchester, UK