| AIM :To investigate the displacement, the position of rotation center and the stress distribution of PDL under different loading force system (Moment/ Force, M/F)by simulating clinical loading force system when loads equal to 1 N on five different levels of the tooth crown. A further aim was to quantify the alteration in stress that occurs as alveolar bone is reduced in height by 1/3,1/2,2/3 respectively.Methods:â‘ To establish a 3-D finite-element model of the upper central incisor By means of CT scanning technology and software of image processing and finite element analyzing program.â‘¡Four three-dimensional (3D) finite element models (FEM) of a human maxillary central incisor were designed. The models were of the same configuration except for the alveolar bone height.â‘¢by application of orthodontic forces at different height: 2.8mm,3.8mm,4.8mm,5.8mm,6.8mm,the displacement, the position of rotation center and the stress distribution of PDL were analyzed under different types of loading force system..Results :â‘ Different force system led to different types of tooth movement. It brought the result of controlled tipping movement, the bodily movement and the root movement;â‘¡The tipping tooth movement is smaller if the force is applied closer its neck, or less gingivally.â‘¢The impression of alveolar bone loss on the tipping tooth movement is more greater than that of different levels of loading.â‘£The results showed that stress distribution had changed with different loading .Conclusions:â‘ It is feasible to establish the teeth and alveolar bone by means of CT scanning technology and software of image processing and finite element analyzing program. The three-dimensional mathematical finite element model is useful in analyzing the tooth movement in response to orthodontic forces.â‘¡Different force system led to different types of tooth movement.â‘¢The tipping tooth movement is... |
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