Abstract
Objective
Methods
Figures and Tables
Figure 1
Three-dimensional finite element model and experimental conditions. A, Finite element method model of periodontal ligament. B, Position of orthodontic miniscrews and direction of the retraction force. C, Coordinate system. x-axis: (+) anterior, (−) posterior direction; y-axis: (+) superior, (−) inferior direction; z-axis: (+) buccal, (−) palatal direction.
![kjod-49-393-g001](/upload/SynapseData/ArticleImage/1123kjod/kjod-49-393-g001.jpg)
Figure 2
Landmarks used for the assessment of displacement. Red dots indicate reference points for the crown and root of each tooth.
![kjod-49-393-g002](/upload/SynapseData/ArticleImage/1123kjod/kjod-49-393-g002.jpg)
Figure 3
Displacement patterns of the central incisor according to archwire stiffness at each given level of friction. Dotted line, initial position. Solid line, position after movement (50× magnification). Positive value, anterior direction of the x-axis and apical direction of the y-axis. W1, 0.016 × 0.022-inch (in) flexible stainless steel (SS); W2, 0.017 × 0.025-in flexible SS; W3, 0.019 × 0.025-in flexible SS; W4, rigid body. F0, µ = 0.0; F1, µ = 0.1; F2, µ = 0.2; F3, µ = 0.3.
![kjod-49-393-g003](/upload/SynapseData/ArticleImage/1123kjod/kjod-49-393-g003.jpg)
Figure 4
Displacement patterns of posterior teeth according to archwire stiffness at each given level of friction. A, Tooth axis displacement patterns (1,000× magnification). B, Posterior occlusal plane displacement patterns (1,500× magnification). Dotted (gray) line, initial position. Solid line, position after displacement. Positive value, anterior direction of the x-axis and apical direction of the y-axis.
![kjod-49-393-g004](/upload/SynapseData/ArticleImage/1123kjod/kjod-49-393-g004.jpg)
Figure 5
Displacement patterns of the central incisor according to friction levels at each given level of archwire stiffness. Dotted line, initial position. Solid line, position after movement (50× magnification). Positive value, anterior direction of the x-axis and apical direction of the y-axis.
![kjod-49-393-g005](/upload/SynapseData/ArticleImage/1123kjod/kjod-49-393-g005.jpg)
Figure 6
Displacement patterns of posterior teeth according to friction levels at each given level of archwire stiffness. A, Tooth axis displacement patterns (1,000× magnification). B, Posterior occlusal plane displacement patterns (1,500× magnification). Dotted (gray) line, initial position. Solid line, position after displacement. Positive value, anterior direction of the x-axis and apical direction of the y-axis.
![kjod-49-393-g006](/upload/SynapseData/ArticleImage/1123kjod/kjod-49-393-g006.jpg)
Figure 7
Displacement patterns resulting from varying levels of archwire stiffness and friction. Relatively low archwire stiffness led to less displacement of the posterior segment compared to that observed with high archwire stiffness across friction levels. A, Flexible archwire with low friction. B, Flexible archwire with high friction. C, Rigid archwire with low friction. D, Rigid archwire with high friction (gray color, original tooth position; brown color, tooth position after displacement).
![kjod-49-393-g007](/upload/SynapseData/ArticleImage/1123kjod/kjod-49-393-g007.jpg)
Table 3
Displacement of the center of resistance of the central incisor and first molar
![kjod-49-393-i003](/upload/SynapseData/ArticleImage/1123kjod/kjod-49-393-i003.jpg)
Positive value, anterior direction of the x-axis and apical direction of the y-axis.
Δ CR x, Displacement amount of the center of resistance in the x-axis; Δ CR y, displacement amount of the center of resistance in the y-axis.
See Figure 3 for definitions of each landmark or measurement.
ACKNOWLEDGEMENTS
Notes
References
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