title: Microtensile specimen attachment and shape--finite element analysis.
abstract: Microtensile bond strength values are influenced by specimen shape and attachment method to the gripping device during testing. We hypothesized that stress distribution inside the testing specimen is affected by microtensile specimen shape and attachment method. Rectangular, hourglass-, and dumbbell-shaped specimens, all with a 1 mm(2) cross-sectional testing region, were modeled as indirect ceramic restorations luted to dentin. Three specimen attachments were investigated: (1) posterior surface; (2) posterior, superior, and lateral surfaces; and (3) all surfaces. Qualitative and quantitative analyses were carried out according to von Mises' criteria. Stress analysis showed a direct correlation between attachment modes and stress distribution, with shear stresses observed in models with less surface attachment. Increasing the number of faces for specimen attachment to the metallic gripping device resulted in a more homogeneous and regular distribution of stress, with tensile stress concentrated at the adhesive interface. Dumbbell-shaped specimens showed improved stress distribution compared with rectangular and hourglass-shaped specimens.
authors: Biomechanics group, School of Dentistry, Federal University of Uberlândia, Av. Pará 1720, Bloco 2B, sala 2B24, 38400-902, Uberlândia, MG, Brazil. carlosjsoares@umuarama.ufu.br
authors: C J
authors: CJ
authors: Soares
authors: P V
authors: PV
authors: Soares
authors: P C F
authors: PC
authors: Santos-Filho
authors: S R
authors: SR
authors: Armstrong
mesh_terms: D017438:Bisphenol A-Glycidyl Methacrylate / Q000737:chemistry; D001840:Dental Bonding / Q000379:methods; D003764:Dental Materials / Q000737:chemistry*; D003776:Dental Porcelain / Q000737:chemistry; D003799:Dental Stress Analysis / Q000295:instrumentation; D003804:Dentin / Q000648:ultrastructure; D004548:Elasticity; D020342:Finite Element Analysis; D006801:Humans; D021621:Imaging, Three-Dimensional; D018020:Lithium Compounds / Q000737:chemistry; D008422:Materials Testing; D011092:Polyethylene Glycols / Q000737:chemistry; D011109:Polymethacrylic Acids / Q000737:chemistry; D019279:Resin Cements / Q000737:chemistry; D013314:Stress, Mechanical; D013499:Surface Properties; D013718:Tensile Strength
chemical_list: D003764:Dental Materials; C118557:Empress 2; D018020:Lithium Compounds; D011109:Polymethacrylic Acids; C462240:RelyX ARC; D019279:Resin Cements; D003776:Dental Porcelain; D011092:Polyethylene Glycols; D017438:Bisphenol A-Glycidyl Methacrylate