Undermining of enamel as a mechanism of abfraction lesion formation: a finite element study

Abstract

Many workers have suggested that abfraction lesion formation is caused by the physical overloading of enamel. However, an alternative mechanism, involving undermining of the cervical enamel along the amelodentinal junction (ADJ), may be a more realistic explanation. The aim of this study was to examine what effect undermining of the buccal cervical enamel would have on the stress distribution in upper teeth. Two-dimensional plain strain finite element meshes of an upper incisor, canine and first premolar and the supporting periodontal ligament and alveolar bone were developed. Each tooth was loaded with an oblique 100 N load, and the nodal maximum principal stresses (MPS) along a buccal horizontal sampling plane 1.1 mm above the amelo-cemental junction was measured. A discontinuity between the cervical enamel and dentine elements was then introduced (0.1 mm wide) using gap elements. The vertical extent of this defect varied from 0.1 to 0.5 mm. The value of the MPS varied from 1.8 to 209 Mpa, and the lowest values were found for the intact teeth (range 0.6-30.3 MPa). The discontinuity caused a dramatic increase in the numerical values of the MPS, and in many instances these exceeded the known failure stress for enamel.

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

“…Contrary to our results, Rees et al 4,14,[33][34][35] proposed that the sampling horizontal planes were chosen at 1.1 ㎜ above the CEJ among the buccal cervical region because an initial pilot study showed this to be the position of maximum stress concentration. Despite their findings, the results of their study must be interpreted with a certain amount of caution.…”

“…More recently, an additional mechanism for cervical tooth loss with occlusal loading has been proposed 2,4) . Grippo 3) has coined the term "abfraction" to distinguish it from lesions caused by erosion and abrasion.…”

The influence of combining composite resins with different elastic modulus on the stress distribution of Class V restoration: a three-dimensional finite element study

“…It is a general rule of engineering that stress will always follow the path of the stiffest material, that is, the path with the highest elastic modulus. In the case of an intact tooth, the stiffest material is the enamel, and an applied occlusal load is generally passed through the enamel and into the underlying dentine, with the load being dissipated through the crown and down into the root in a radial and apical direction 28) . Therefore, strictly from a mechanical point of view, it can be said that the best approach is to apply restorative materials with high Young' s modulus as possible.…”

“…A direct, quantitative comparison between the stresses generated by these techniques has been made. Two-dimensional axisymmetric finite element modeling has been used in most previous research 22,23,28) . Although numerical results can be easily obtained in two dimensional modeling, it has some significant shortcomings.…”

Effects of occlusal load on the stress distribution of four cavity configurations of noncarious cervical lesions: a three-dimensional finite element analysis study

“…More recently, an additional mechanism for cervical tooth loss that links with occlusal loading has been proposed 2,3,5,7) . There is some clinical evidence for the association of abfraction lesions with heavy occlusal loads.…”