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Scientific Section |
Department of Dental Health & Development and Biomechanics Unit, Department of Basic Dental Science, University of Wales College of Medicine, Cardiff CF64 3NY, UK
Abstract
The aim of the study was to develop a 3D computer model of the movement of a maxillary incisor tooth when subjected to an orthodontic load. A novel method was to be developed to directly and accurately measure orthodontic tooth movement in a group of human volunteers. This was to be used to validate the finite element-based computer model.
The design took the form of a prospective experiment at a laboratory at the University of Wales in 1996/7.
A laser apparatus was used to sample tooth movement every 001 seconds over a 1-minute cycle for 10 healthy volunteers, whilst a constant 039 N load was applied. This process was repeated on eight separate occasions and the most consistent five readings taken for each subject. Data were used to calculate the physical properties of the periodontal ligament (PDL). The data gleaned by this method were used to validate the 3D FEM model. This was formed of 15,000 four-noded tetrahedral elements.
Tooth displacements ranged from 0012 to 0133 mm. An appropriate elastic modulus of 1 N/mm2 and Poisson's Ratio of 045 was derived for the PDL. Strain analysis, using the model, suggested that a maximum PDL strain of 477 x 103 was recorded at the alveolar crest, while the largest apical strain recorded was 155 x 103. The maximum strains recorded in the surrounding alveolar bone were 35 times less than for the PDL.
A novel method for direct measurement of PDL physical properties in the human subject has been developed. The validated FEM model lends further evidence that the PDL is the main mediator of orthodontic tooth movement.
Key words: Experimental Validation, FEM modelling, Laser Measurement, Periodontal Ligament Properties, Tooth Movement
Notes
2 Present address: Glasgow Dental School, Glasgow, UK.
This article has been cited by other articles:
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P.M. Cattaneo, M. Dalstra, and B. Melsen The Finite Element Method: a Tool to Study Orthodontic Tooth Movement J. Dent. Res., May 1, 2005; 84(5): 428 - 433. [Abstract] [Full Text] [PDF] |
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