Layered Orthodontic Shell Structure for Precise Tooth Force Control
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Solution Overview
Problem
Current orthodontic appliances often fail to generate the necessary forces for effective tooth repositioning and provide insufficient control over applied forces, leading to discomfort and reduced efficacy in orthodontic treatments.
Innovation Solution
The development of orthodontic appliances with a layered structure featuring a stiffer exterior layer and a less stiff interior layer, incorporating discontinuities that interact with the interior layer to generate controlled forces for tooth movement, thereby enhancing force application and reducing patient discomfort.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a single appliance shell with homogeneous material properties is used, then the appliance structure is simple, but the force generation and control capability is insufficient
Solution Approach 1:
The appliance shell is divided into multiple layers (exterior layer and interior layer) with different material properties. The exterior layer has greater stiffness while the interior layer has lesser stiffness, allowing each layer to contribute differently to force generation and control, thereby resolving the contradiction between force capability and structural simplicity.
Solution Approach 2:
Different regions of the appliance shell are assigned different stiffness characteristics through the layered structure. The exterior layer provides structural integrity and force transmission, while the interior layer provides flexibility and comfort, enabling localized optimization of force properties without uniformly increasing complexity throughout the entire appliance.
2Force
If the appliance rigidity is increased, then the force control capability is improved, but the ability to be coupled to patient's teeth is interfered with and patient discomfort increases
Solution Approach 1:
The appliance is segmented into a rigid exterior layer for force control and a flexible interior layer for comfort and coupling. This segmentation allows the exterior layer to maintain high rigidity for precise force control while the interior layer maintains low rigidity to conform to patient's teeth and reduce discomfort, resolving the contradiction between force control and ease of operation.
Solution Approach 2:
The layered structure creates local quality differences where the exterior layer exhibits high rigidity for force control in regions requiring structural stability, while the interior layer exhibits low rigidity in regions requiring adaptability to patient's teeth, thereby simultaneously achieving force control capability and patient comfort without compromising either.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The layered design with discontinuities allows for precise and controlled force application, improving orthodontic treatment outcomes by facilitating more effective tooth repositioning with reduced discomfort.
Implementation Method 1
The shell can include an exterior layer and an interior layer having a stiffness less than that of the exterior layer
Data Source
AI summary
Methods for fabricating layered appliances are provided. In some embodiments, a method includes generating a digital model of a polymeric shell including a plurality of tooth-receiving cavities shaped to receive and reposition a patient's teeth from a first arrangement toward a second arrangement. The polymeric shell can include an interior layer having a first stiffness, and an exterior layer having a second stiffness greater than the first stiffness. The exterior layer can include a discontinuity formed therein. The method can further include transmitting the digital model to a fabrication system configured to fabricate the polymeric shell based on the digital model.