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Botto A.P.,Instituto Polytechnic Of Saude Do Norte Cespu | Vaz M.A.,University of Porto | Ustrell J.M.,University of Barcelona
Biodental Engineering III - Proceedings of the 3rd International Conference on Biodental Engineering, BIODENTAL 2014 | Year: 2014

The apparatus, Quad-helix, appeared after modifications done by Ricketts in 1975, with the purpose of allowing a dental expansion with soft and more prolonged forces [2]. Currently the apparatus activation in the clinical practice has been done in an empirical way having as main criteria an expansion as fast as possible as long as the patient can bear it. Twenty four Quad-helix apparatus were made, twelve of them fixed and twelve removable with 20, 25 and 30 mm orthodontic wire of RemaniumR and RemaloyR Dentaurum steel in 0.9 and 1 mm thickness. The mechanical tests were done in a setup with a load cell to measure the forces of the Quad-helix apparatus, when submitted to a 0.5 to 5 mm displacement between both ends. When some parameters such as, the Quad-helix confection method (fixed and removable), the alloy used to make the apparatus (Remanium(R)-Remaloy(R)), the thickness of the orthodontic wire (0.9 mm-1 mm) and the size of the Quad-helix (20 mm-25 mm-30 mm) changed, we found some significative statistical evidence which allow us to assume there are differences between the average forces exerted by the Quad-helix. © 2014 Taylor & Francis Group. Source


Botto A.P.,Instituto Polytechnic Of Saude Do Norte Cespu | Vaz M.A.,University of Porto | Ustrell J.M.,University of Barcelona
Biodental Engineering III - Proceedings of the 3rd International Conference on Biodental Engineering, BIODENTAL 2014 | Year: 2014

When the Quad-helix appliance undergoes activation, it changes its geometric configuration. However the clinician never knows for sure how the force is distributed within the appliance at the time of activation. In this research study the aim was to study the behavior of fixed and removable Quad-helix appliances, so we acquire a broader knowledge on what kind of deformation these appliances suffer when subjected to a force. The software used to achieve the 3D geometric designs were: SolidWorksR and a post-processing program that comes with the Ansys code for the numerical simulation. It has been found that, for the Quad-helix fixed appliances, helicoids suffer greater stress and hence greater deformation, while for the removable Quad-helix appliances, the posterior loops are the point of maximum stress and stress. The geometric configuration of a Quad-helix, (fixed or removable) is an important factor to consider at the time of activation of the appliance. © 2014 Taylor & Francis Group. Source

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