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. 2013 Nov;10(6):777-83.

Comparison of the skeletal and dental changes of tooth-borne vs. bone-borne expansion devices in surgically assisted rapid palatal expansion: A finite element study

Azita Tehranchi  1 , Nazila Ameli  2 , Zahra Najirad  3 , Fatemeh Sadat Mirhashemi  4
Affiliations

Comparison of the skeletal and dental changes of tooth-borne vs. bone-borne expansion devices in surgically assisted rapid palatal expansion: A finite element study

Azita Tehranchi et al. Dent Res J (Isfahan). 2013 Nov.

Abstract

Background: The aim of this study was to compare the skeletal and dental changes of a tooth-borne (Hyrax) and a bone-borne (Smile distractor) expansion devices using three-dimensional model of a human skull.

Materials and methods: A finite element model of human skull was generated using data from 3-D CT scans of an 11-year-old female child. Then a Hyrax expander (tooth-borne appliance) and Smile distractor (bone-borne appliance) in three different positions were adapted to the finite element model and expanded for 0.5 mm simulating the clinical situation. The 3-D pattern of displacement and stress distribution was then analyzed.

Results: The results of this study showed that screw position affects the stress and displacement pattern within the nasomaxillary complex and maxillary dental arch.

Conclusion: Closer teeth feel more stress and undergo more displacement than the farther ones. Moreover, skeletal effects of the Smile distractor were greater than of Hyrax in all different positions.

Keywords: Dental; expansion device; finite element method; skeletal.

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Conflict of interest statement

Conflict of Interest: None declared.

Figures

Figure 1
Figure 1
Teeth displacement (millimeter) (a) Hyrax 1 (b) Hyrax 2 (c) Hyrax 3 (d) Smile distractor 1 (e) Smile distractor 2 (f) Smile distractor 3
Figure 2
Figure 2
Transverse displacement of mid-face skeleton (millimeter) (a) Hyrax 1 (b) Hyrax 2 (c) Hyrax 3 (d) Smile distractor 1 (e) Smile distractor 2 (f) Smile distractor 3
Figure 3
Figure 3
Stress of Von-Mises in PDL of first premolar (left) and molar (right) teeth (MPa) (a) Hyrax 1 (b) Hyrax 2 (c) Hyrax 3 (d) Smile distractor 1 (e) Smile distractor 2 (f) Smile distractor 3
See this image and copyright information in PMC

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