title: Effect of tubule orientation and dentin location on the microtensile strength of bovine root dentin.
abstract: To investigate the mechanical properties of root dentin and to further clarify the cause of vertical root fracture (VRF), this study evaluated the effect of tubule orientation (parallel, perpendicular and oblique to the cross-section of dumbbell specimens in microtensile tests) and dentin location (cervical, middle, and apical location of the root) on the microtensile strength of bovine root dentin. Each specimen was stressed in tension at a crosshead speed of 1.0 mm/min. The results of the microtensile strength measurements were statistically analyzed with one-way ANOVA and the Fisher PLSD. The oblique group (95.18+/-23.80 MPa) was significantly (p<0.01) higher than the parallel group (38.93+/-5.28 MPa) or the perpendicular group (32.64+/-4.69 MPa). There were no significant differences among the different dentin locations within the parallel group (p>0.05). It was clarified that the VRF occurs frequently in practical situations due to the tubule orientation of root dentin.
authors.affiliation: Department of Dental Materials Science, Tokyo Dental College, Chiba, Japan.
authors.forename: Jia
authors.initials: J
authors.lastname: Liu
authors.forename: Masayuki
authors.initials: M
authors.lastname: Hattori
authors.forename: Koji
authors.initials: K
authors.lastname: Hasegawa
authors.forename: Masao
authors.initials: M
authors.lastname: Yoshinari
authors.forename: Eiji
authors.initials: E
authors.lastname: Kawada
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Oda
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D002417:Cattle; D003799:Dental Stress Analysis; D003804:Dentin / Q000502:physiology / Q000648:ultrastructure*; D008855:Microscopy, Electron, Scanning; D013223:Statistics as Topic; D013314:Stress, Mechanical; D013718:Tensile Strength; D014082:Tooth Fractures / Q000473:pathology / Q000503:physiopathology; D014092:Tooth Root / Q000293:injuries / Q000502:physiology / Q000648:ultrastructure*