Analysis of the Abfraction Lesions Formation Mechanism by the Finite Element Method

Abstract

Introduction:An abfraction lesion is a type of a non-carious cervical lesion (NCCL) that represents a sharp defect on the cervical part of tooth, caused by occlusal biomechanical forces. The largest prevalence of the NCCL is found on the mandibular first premolar. The goal of the study is, by means of a numerical method – the finite element method (FEM), in an appropriate computer program, conduct a stress analysis of the mandibular premolar under various static loads, with a special reference to the biomechanics of cervical tooth region.Material and methods:A three-dimensional model of the mandibular premolar is gained from a µCT x-ray image. By using the FEM, straining of the enamel, dentin, peridontal ligament and alveolar bone under axial and paraxial forces of 200 [N] is analyzed. The following software were used in the analysis: CT images processing–CTAn program and FEM analysis–AnsysWorkbench 14.0.Results:According to results obtained through the FEM method, the calculated stress is higher with eccentric forces within all tested tooth tissue. The occlusal load leads to a significant stress in the cervical tooth area, especially in the sub-superficial layer of the enamel (over 50 MPa). The measured stress in the peridontal ligament is approximately three times higher under paraxial load with regard to the axial load, while stress calculated in the alveolar bone under paraxial load is almost ten times higher with regard to the axial load. The highest stress values were calculated in the cervical part of the alveoli, where bone resorption is most commonly seen.Conclusion:Action of occlusal forces, especially paraxial ones, leads to significant stress in the cervical part of tooth. The stress values in the cervical sub-superficial enamel layer are almost 5 times higher in relation to the superficial enamel, which additionally confirms complexity of biomechanical processes in the creation of abfraction lesions.

Understanding Dental Caries

“…Abfraction lesions result from the stress in the cervical subsuperfi cial enamel layer, which is almost fi ve times higher compared with the superfi cial enamel (Jakupovic et al 2014 ). Using an appropriate computer program (the fi nite element method), the authors came to the conclusion that action of occlusal forces, especially paraxial ones, leads to signifi cant stress in the cervical part of the tooth.…”

Noncarious Cervical Lesions: Correlation between Abfraction and Wear Facets in Permanent Dentition

“…This will allow the water or other small molecules to penetrate the broken hydroxyapatite chemical bonds making the tooth susceptible to chemical erosion or less resistant to abrasive factors [10]. The discovery of well-demarcated and flattened shiny areas on the chewing surfaces of the teeth, known as wear facets, can reveal a stressful occlusion by tooth-tooth interaction [11]. The finding of wear facets in teeth with wedge-shaped NCCLs should give more validation to occlusal stress as causative agent and in some cases should be considered as the initial event in absence of other recognizable causative factors [12].…”

Comparison of the Postoperative Sensitivity using Two Flowable Composites in Noncarious Cervical Lesions: A Randomized Blinded Clinical Trial

“…1 These lesions include abrasion, corrosion, and (possibly) abfraction, acting independently or in combination. Detailed case history and extension of cavity depth should be taken into consideration before restoring the NCCLs.…”