Biomechanical investigation into the role of the periodontal ligament in optimising orthodontic force: a finite element case study. (June 2016)

• Record Type: Journal Article
• Authors: Liao, Zhipeng; Chen, Junning; Li, Wei; Darendeliler, M. Ali; Swain, Michael; Li, Qing
• Is Part Of: Archives of oral biology. Volume 66(2016)
• Page Start: 98
• Page End: 107
• Publication Date: 2016-06
• Subjects: Hyperelastic model -- Hydrostatic stress -- Periodontal ligament -- Optimal orthodontic forces -- Periodontal interstitial fluid; Mouth -- Periodicals; Mouth -- Diseases -- Periodicals; Dentistry -- Periodicals; Electronic journals; 617.6005
• DOI: 10.1016/j.archoralbio.2016.02.012
• Languages: English
• ISSNs: 0003-9969

Abstract

Highlights: Accurate CRe localisation should be necessitated and can be achieved through 3D patient-specific modelling. The optimal force can be evaluated by establishing thresholds based on the "OTM effective zone". The optimal force should be close to and smaller than the upper bound of the optimal range corresponding to 16 KPa. The global hydrostatic pressure sustained by the PDL directly correlates with the optimal orthodontic force. Only when the majority of the PDL volume is effectively stressed, OTM can occur. Abstract: Objectives: This paper aimed to precisely locate centres of resistance (CRe) of maxillary teeth and investigate optimal orthodontic force by identifying the effective zones of orthodontic tooth movement (OTM) from hydrostatic stress thresholds in the periodontal ligament (PDL). Methods: We applied distally-directed tipping and bodily forces ranging from 0.075 N to 3 N (7.5 g to 300 g) onto human maxillary teeth. The hydrostatic stress was quantified from nonlinear finite element analysis (FEA) and compared with normal capillary and systolic blood pressure for driving the tissue remodelling. Two biomechanical stimuli featuring localised and volume-averaged hydrostatic stresses were introduced to describe OTM. Locations of CRe were determined through iterative FEA simulation. Results: Accurate locations of CRes of teeth and ranges of optimal orthodontic forces were obtained. By comparing with clinical results in literature, the volume average of hydrostatic stress in PDL was proved to describe the process of OTM more indicatively. The optimal orthodontic forces obtained from the in-silico modelling study echoed with the clinical results in vivo. Conclusions: A universal moment to force (M/F) ratio is not recommended due to the variation in patients and loading points. Accurate computational determination of CRe location can be applied in practice to facilitate orthodontic treatment. Global measurement of hydrostatic pressure in the PDL better characterised OTM, implying that OTM occurs only when the majority of PDL volume is critically stressed. The FEA results provide new insights into relevant orthodontic biomechanics and help establish optimal orthodontic force for a specific patient.