The Biomechanical Function of Periodontal Ligament Fibres in Orthodontic Tooth Movement

Abstract

Orthodontic tooth movement occurs as a result of resorption and formation of the alveolar bone due to an applied load, but the stimulus responsible for triggering orthodontic tooth movement remains the subject of debate. It has been suggested that the periodontal ligament (PDL) plays a key role. However, the mechanical function of the PDL in orthodontic tooth movement is not well understood as most mechanical models of the PDL to date have ignored the fibrous structure of the PDL. In this study we use finite element (FE) analysis to investigate the strains in the alveolar bone due to occlusal and orthodontic loads when PDL is modelled as a fibrous structure as compared to modelling PDL as a layer of solid material. The results show that the tension-only nature of the fibres essentially suspends the tooth in the tooth socket and their inclusion in FE models makes a significant difference to both the magnitude and distribution of strains produced in the surrounding bone. The results indicate that the PDL fibres have a very important role in load transfer between the teeth and alveolar bone and should be considered in FE studies investigating the biomechanics of orthodontic tooth movement.

A porous fibrous hyperelastic damage model for human periodontal ligament: Application of a microcomputerized tomography finite element model

“…By contrast, the formation of bone tissue can be explained by fibre stretching . The maximum value of the maximal principal stresses can be found in the apical region of the PDL (see Figure A).…”

“…[74][75][76] By contrast, the formation of bone tissue can be explained by fibre stretching. [77][78][79] The maximum value of the maximal principal stresses can be found in the apical region of the PDL (see Figure A2A). The over-elongation of fibres in this region causes fibrous network damage ( Figure 7C), local vascularization, 69 and mechanobiological signals (arachidonic acid metabolites, neuropeptides, or cytokines).…”

Three‐dimensional finite element stress analysis of teeth adjacent to a traumatized incisor

“…Deformation and stresses are mediated between teeth and bone by the PDL . Injury to the PDL is thought to play an important role in the mechanisms of tooth trauma and tooth mobility . Displacement, which was also demonstrated on teeth adjacent to the impacted incisor, can interrupt vascular blood supply and cause pulp necrosis which is one of the predisposing factors for inflammatory root resorption …”

“…24 Injury to the PDL is thought to play an important role in the mechanisms of tooth trauma and tooth mobility. 25 Displacement, which was also demonstrated on teeth adjacent to the impacted incisor, can interrupt vascular blood supply and cause pulp necrosis which is one of the predisposing factors for inflammatory root resorption. 26,27 The 10 m/s velocity of impact was based on previous studies in which bicycle accidents were shown to be common causes for dental trauma.…”

Reliable quantification of bite-force performance requires use of appropriate biting substrate and standardization of bite out-lever

“…In humans and other mammals, such mechanoreceptors that are sensitive to local mechanical stimuli (e.g. encoding information on the hardness and stiffness of an item being bitten) are found in the periodontal ligament that surrounds the tooth root and suspends it in the socket (Hannam, 1969;Yamaguchi et al, 2012;McCormack et al, 2014). Lizards do not possess a periodontal ligament, but similar mechanoreceptors are almost certainly present in the dentine (Dong et al, 1985;Dong et al, 1993;Kieser et al, 2009;Kieser et al, 2011) and less certainly in the pulp cavity (Paphangkorakit and Osborn, 1997;Paphangkorakit and Osborn, 1998), jaw joints (Curtis et al, 2010b), skull sutures , bones (Jacobs and van Steenberghe, 1993) and soft tissues of the mouth, such as the tongue (Paphangkorakit and Osborn, 1998 Fig.…”