title: Abfraction and anisotropy--effects of prism orientation on stress distribution.
abstract: This work discusses the effect of enamel anisotropy in the stress concentration at the cement-enamel junction (CEJ), a probable cause of fracture in enamel leading to abfraction. Usual simplifications when developing computer models in dentistry are to consider enamel isotropic, or that the direction of the prisms is orthogonal to either the dentine-enamel interface or the tooth outer surface. In this paper, a more refined model for the material behavior is described, based on laboratory observation and on the work of Fernandes and Chevitarese. The material description is used in a two-dimensional (2D) finite element model of the first upper premolar, and the analysis is performed for two different situations: vertical loads, typical of normal mastication and horizontal loads, dominant in bruxism. The analyses were performed using a unit load, which under the hypothesis of linear response of the tooth, allows the combinations described in the text to simulate different functional and parafunctional loads. The results indicate that a realistic enamel description in terms of mechanical properties and spatial distribution of its prisms alters significantly the resulting stress distribution. For all cases included in this study, the detailed description of prism orientation and resulting anisotropy led to improved response in terms of stress distribution, even when loading was horizontal.
authors.affiliation: School of Engineering, Federal University of Minas Gerais (UFMG) Av. do Contorno 842, 30320-020- Belo Horizonte, MG, Brazil. estevam@dees.ufmg.br
authors.forename: Estevam B
authors.initials: EB
authors.lastname: De Las Casas
authors.forename: Tulimar P M
authors.initials: TP
authors.lastname: Cornacchia
authors.forename: Priscila H
authors.initials: PH
authors.lastname: Gouvêa
authors.forename: Carlos Alberto
authors.initials: CA
authors.lastname: Cimini
mesh_terms: D016880:Anisotropy; D001641:Bicuspid / Q000503:physiopathology*; D001732:Bite Force; D002012:Bruxism / Q000150:complications / Q000503:physiopathology; D003743:Dental Enamel / Q000503:physiopathology*; D003799:Dental Stress Analysis / Q000379:methods*; D017886:Durapatite; D004548:Elasticity; D020342:Finite Element Analysis; D006801:Humans; D008954:Models, Biological; D012680:Sensitivity and Specificity; D013314:Stress, Mechanical; D013718:Tensile Strength; D014072:Tooth Abrasion / Q000209:etiology / Q000503:physiopathology*; D019217:Tooth Attrition / Q000503:physiopathology; D019237:Tooth Cervix / Q000503:physiopathology*; D016474:Weight-Bearing
chemical_list: D017886:Durapatite