fa An in vitro investigation of the effect of bevel design on the penetration and withdrawal forces of dental needles سلامت دهان و جامعه نگر Oral Health and Epidemiology پژوهشي Research <p> <strong>Objectives</strong></p><p>  To compare the effect on insertion and withdrawal forces using needles with a standard atraumatic bevel to those with a novel asymmetrical bevel in vitro. </p><p> <strong>Methods</strong> </p><p> Maximum needle penetration forces were measured using a 10N load cell mounted on an Instron universal testing machine. Forces were determined during insertion through a 0.4mm polyurethane membrane mounted at 90° (n=30 of each design), 30° (n=16 of each design) and 150° (n=16 of each design) to the needle bevel and during a 10mm insertion into a polyvinyl siloxane block mounted at 90° to the bevel (n=16 of each design). In all tests the rate of insertion was 50mm/min. </p><p> <strong>Results</strong></p><p>  The novel design required less force to penetrate the membrane at 30° and 150° compared to the standard design (mean forces at 30° being 0.75N and 0.98N for novel and standard designs respectively [p<0.001] and at 150° 0.52N and 0.66N respectively [p<0.001] but more force at 90° penetration tests (0.60N and 0.46N respectively [p<0.001]). The novel design required less force to insert 10mm into the polyvinyl siloxane (1.80N and 2.54N respectively [p<0.001]). </p><p> <strong>Conclusion</strong></p><p>  The novel design needed less force than the standard version to penetrate a thin membrane when used at 30° and 150° to the surface and to penetrate a polyvinyl siloxane block to a depth of 10mm but required more force to penetrate a thin membrane at 90°. </p><p> <strong>Clinical significance</strong> </p><p> Needle bevel design affects the penetration and withdrawal forces of dental needles in vitro. </p><p>  </p><hr><p></p><p> <strong>Source: </strong>Journal of Dentistry</p><p><a href="http://www.jodjournal.com/article/S0300-5712(12)00300-4/abstract" target="_blank"><font color="#0000ff"> Full Text</font></a></p> Dental, Needle, Bevel, Penetration, In vitro 0 0 http://idai.ir/browse.php?a_code=A-10-32-2110&slc_lang=fa&sid=1 A.C. Steele 10031947532846009892 10031947532846009892 No Centre for Oral Health Research, School of Dental Sciences, Newcastle University, Framlington Place, Newcastle Upon Tyne NE 2 4BW, UK M.J. German 10031947532846009893 10031947532846009893 No Centre for Oral Health Research, School of Dental Sciences, Newcastle University, Framlington Place, Newcastle Upon Tyne NE 2 4BW, UK J. Haas 10031947532846009894 10031947532846009894 No Septodont, 58, rue du Pont de Créteil, 94107 Saint-Maur-des-fossés Cedex, France ?G. Lambert 10031947532846009895 10031947532846009895 No Septodont, 58, rue du Pont de Créteil, 94107 Saint-Maur-des-fossés Cedex, France J.G Meechan 10031947532846009896 10031947532846009896 Yes Centre for Oral Health Research, School of Dental Sciences, Newcastle University, Framlington Place, Newcastle Upon Tyne NE 2 4BW, UK