Laboratorija za Rapid Prototyping i Reverse Engineering

S. Jakupović, E. Cerjaković, A. Topčić, M. Ajanović, A. Konjhodžić-Prcić: „Analysis of the Abfraction Lesions Formation Machanism by the Finite Element Method“, Journal: Acta Informatica Medica, Vol. 22, Issue: 4, format A4, page 241÷245 /5  pages/, ISSN 0353-8109 (Print), ISSN 1986-5988 (Online), Sarajevo 2014

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.
Key words: abfraction, finite element method, occlusion, stress.