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.

Three-dimensional finite element analysis of the maxillary central incisor in two different situations of traumatic impact

“…This finding agrees with epidemiological data showing a low prevalence of root fracture among dental trauma (Majorana et al 2002;Andreassen et al 2004). Similar stress distribution can be found in the studies on bruxism, in which a build-up of stress concentration was found in the cervical regions; however, this type of situation will only be able to generate clinical consequences when applied over a long period of time, resulting in non-carious cervical lesions (De Las Casas et al 2003;Dejak et al 2005).…”

Effects of occlusal load on the cervical stress distribution: A three-dimensional finite element study

“…The position of maximum stress concentration found in this study was different from previous studies [29][30][31][32] . This pattern of stress distribution may be related to the anatomical asymmetry.…”

“…Many studies 11,13,15,16,[29][30][31] reported that the peak stress was concentrated at the CEJ in their FEA models. Kuroe et al 32) also confirmed by the photoelastic method that a vertical force loaded on the tooth causes stress con- Compressive strength of dentin 249 -347…”

Stress distribution on maxillary central incisorunder similar traumatic situations with different loading forces: a 3-D finite element analysis.

“…24 Similar stress distribution can be found in studies on bruxism, in which a buildup of stress concentration could be identified in the cervical regions; however, this type of situation will only be able to generate clinical consequences when applied over a long period of time, resulting in non-carious cervical lesions. 9,25 In both simulations, the tensile zone was found on the buccal surface and the compressive zone on the palatal surface. This simulation was characterized by a larger area of stress convergence originating from compression against the palatal alveolar bone crest and the accumulation of stress dissipated by the enamel.…”