Laterally Offset Aligner Hooks for Elastic Occlusion Force
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Solution Overview
Problem
Existing orthodontic treatments using shell aligners face challenges in generating sufficient tension force between upper and lower teeth to achieve desired occlusion, as traditional bonding methods are limited by the aligner's geometry, leaving little room for brackets.
Innovation Solution
The development of orthodontic positioning appliances with hooks configured to interface with orthodontic elastic members, allowing for the transfer of forces from the elastic members into the appliances, which can supplement or enhance the repositioning forces applied to the teeth, including designs with laterally or gingivally offset hooks and reinforcement structures to minimize deflection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If shell aligners are designed to match the geometry of a patient's teeth, then the aligner fits the teeth well, but there is little room for bonding brackets to generate tension force with elastic members
Solution Approach 1:
The aligner is segmented by creating localized openings or cutouts in the shell structure at specific tooth positions. These openings provide dedicated spaces for bonding brackets while preserving the overall anatomical fit of the aligner to the teeth. The segmentation allows the aligner to simultaneously maintain its conformal fit and provide attachment points for elastic members.
Solution Approach 2:
Brackets are introduced as intermediary components that bridge between the elastic members and the aligner shell. The brackets bond to the teeth through the aligner openings and provide attachment points for the elastic members, enabling tension force generation without compromising the aligner's anatomical fit. The intermediary brackets resolve the conflict between fit and versatility.
2Reliability
If brackets are bonded to teeth to use elastic members for generating tension force, then occlusion can be improved, but the aligner geometry is constrained and comfort may be reduced
Solution Approach 1:
The aligner maintains its smooth, conformal surface quality over most of its area to ensure patient comfort, while locally modified regions with openings or cutouts are introduced only where brackets need to be bonded. This localized modification approach preserves the overall comfort of the aligner while providing the necessary functionality for elastic member attachment at specific sites.
3Force
If hooks are added to the aligner for elastic member attachment, then tension force can be generated, but the aligner structure becomes more complex and may experience increased deflection
Solution Approach 1:
Instead of adding complex hook structures to the aligner, the design extracts the attachment function by creating simple openings or cutouts in the shell. The elastic members attach directly to the aligner through these openings, eliminating the need for additional hook components. This approach generates the necessary tension force while minimizing structural complexity and avoiding excessive deflection.
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
These appliances effectively generate and supplement repositioning forces, enabling better occlusion and tooth alignment by utilizing elastic members, while maintaining comfort and reducing material deflection.
Implementation Method 1
an orthodontic elastic member to generate a tension force between a patient's upper and lower teeth
Implementation Method 2
reinforcement structures to minimize deflection
Data Source
AI summary
A method of designing a patient removable tooth positioning appliance may include receiving a digital representation of teeth of the patient in a selected arrangement and modeling the patient removable tooth positioning appliance having tooth receiving cavities shaped to receive and apply a resilient positioning force to the teeth of the patient based on the digital representation. The method may also include modeling a hook integral to the patient removable tooth positioning appliance and configured to interface with an elastic member so as to react a force from the elastic member into the appliance. The hook may be configured to be laterally offset from a portion of a tooth receiving cavity of the tooth receiving cavities. The method may also include outputting a three-dimensional representation of the patient removable tooth positioning appliance having the hook for fabrication by one or more fabrication machines.