The effect of various loading scenarios on the stress-strained state of mandible anterior teeth with periodontitis immobilized by splints; finite element analysis

D.A. Gribov, A.E. Krupnin, I.M. Levchenko, D.S. Butkov, S.D. Arutyunov

Abstract: A 3-dimensional finite element model of the mandible anterior part was developed, which included a segment of the mandible bone tissue, two lower canines and four lower incisors (43, 33 and 42, 41, 31, 32, respectively, according to FDI World Dental Federation notation for teeth numbering), a periodontium and the immobilizing splint made of polymethylmethacrylate (PMMA), 0.5 mm thick. Destructive changes in periodontal tissues during periodontitis (exposure of the tooth root) were modelled by deactivating a certain part of the finite elements of the incisors 41, 31, 32 periodontal model. The study examined three scenarios for the functional load: 1 - on four incisors; 2 - on two central incisors; 3 - to the incisor 31 located outside the dental arch. The typical value of the occlusal force, which is F = 50 N and acts on each tooth, was taken as a functional load. For all design cases, the angle of the functional load varied from 0 ° (vertical direction) to 60° in 15° Increments. As a result of the study, it was found that a decrease in the total value of the functional load acting on the teeth leads to both: a decrease in the total displacements and the equivalent stresses in all components of the model, with the exception of tooth 31, where the equivalent stresses are at their maximum in Case 3; it is shown that an increase in the load application angle leads to an increase in all the determined parameters for almost every component of the model; it was found that the obtained values of the maximum equivalent stresses in the splint are concentrated in the interdental space and significantly exceed the accepted strength limit of PMMA; the expediency of installing the extreme sections of the splint on "healthy" teeth has been proven.

Series on Biomechanics, Vol.34, No.1 (2020), 12-19

Keywords: finite element method; Parodontitis; personalized biomechanical analysis

Date published: 2020-04-03