Skeletal response to maxillary protraction with and without maxillary expansion: A finite element study

Gautam, Pawan and Valiathan, Ashima and Adhikari, Raviraj (2009) Skeletal response to maxillary protraction with and without maxillary expansion: A finite element study. American Journal of Orthodontics and Dentofacial Orthopedics. pp. 723-728. ISSN 0889-5406

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The purpose of this finite element study was to evaluate biomechanically 2 treatment modalities—maxillary protraction alone and in combination with maxillary expansion—by comparing the displacement of various craniofacial structures. Methods: Two 3-dimensional analytical models were developed from sequential computed tomography scan images taken at 2.5-mm intervals of a dry young skull. AutoCAD software (2004 version, Autodesk, San Rafael, Calif) and ANSYS software (version 10, Belcan Engineering Group, Cincinnati, Ohio) were used. The model consisted of 108,799 solid 10 node 92 elements, 193,633 nodes, and 580,899 degrees of freedom. In the first model, maxillary protraction forces were simulated by applying 1 kg of anterior force 30� downward to the palatal plane. In the second model, a 4-mm midpalatal suture opening and maxillary protraction were simulated. Results: Forward displacement of the nasomaxillary complex with upward and forward rotation was observed with maxillary protraction alone. No rotational tendency was noted when protraction was carried out with 4 mm of transverse expansion. A tendency for anterior maxillary constriction after maxillary protraction was evident. The amounts of displacement in the frontal, vertical, and lateral directions with midpalatal suture opening were greater compared with no opening of the midpalatal suture. The forward and downward displacements of the nasomaxillary complex with maxillary protraction and maxillary expansion more closely approximated the natural growth direction of the maxilla. Conclusions: Displacements of craniofacial structures were more favorable for the treatment of skeletal Class III maxillary retrognathia when maxillary protraction was used with maxillary expansion. Hence, biomechanically, maxillary protraction combined with maxillary expansion appears to be a superior treatment modality for the treatment of maxillary retrognathia than maxillary protraction alone. (Am J Orthod Dentofacial Orthop 2009;135:723-8)

Item Type: Article
Subjects: Dentistry > MCODS Manipal > Orthodontics
Engineering > MIT Manipal > Mechanical and Manufacturing
Depositing User: MIT Library
Date Deposited: 31 Mar 2016 14:33
Last Modified: 31 Mar 2016 14:33

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