Attachment Placement Appliance Geometry for Accurate Orthodontic Force Control
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Solution Overview
Problem
Existing orthodontic appliances often lack sufficient control over force application to teeth, are sensitive to manufacturing tolerances, and have inaccurate attachment placement, leading to less than ideal tooth movement accuracy and efficiency.
Innovation Solution
Orthodontic appliances with heterogeneous properties, featuring a stiff outer shell and compliant inner structure, provide customized force and torque distribution through localized stiffness variations, improving accuracy and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If homogeneous material properties are used in orthodontic appliances, then manufacturing is simpler, but control over force application to different teeth is insufficient
Solution Approach 1:
The patent applies local quality by varying the material properties (stiffness, elasticity) at different locations within the orthodontic appliance. Different regions of the appliance are designed with customized material characteristics to provide precise control over force application to specific teeth, while still allowing for efficient manufacturing through modern techniques like 3D printing and multi-material injection molding.
Solution Approach 2:
The patent utilizes composite materials by combining multiple materials with different mechanical properties within a single orthodontic appliance. This allows certain regions to be stiffer for structural support and force generation, while other regions are more compliant for comfortable tooth engagement, thereby achieving both manufacturing feasibility and precise force control.
2Force
If stiff orthodontic appliances are used, then force generation is improved, but manufacturing tolerances must be tighter which increases complexity
Solution Approach 1:
The patent applies parameter changes by varying the stiffness parameter locally throughout the appliance rather than using a uniformly stiff structure. By adjusting material composition, thickness, and cross-sectional geometry at different locations, the appliance generates sufficient force where needed while maintaining manufacturing feasibility in other regions, thereby reducing overall manufacturing tolerance requirements.
Solution Approach 2:
The patent implements local quality by concentrating stiff material properties only in specific regions where force generation is critical, while using more compliant materials in regions where precision is less demanding. This localized approach to stiffness reduces the need for tight manufacturing tolerances across the entire appliance while maintaining adequate force generation capability.
3Manufacturing precision
If accurate attachment placement is required, then tooth movement precision is improved, but the appliance design becomes more complex
Solution Approach 1:
The patent applies preliminary action by pre-defining attachment locations and geometries during the digital design and fabrication process. Attachments are precisely positioned on teeth before the appliance is fabricated, and the appliance is then customized to engage these pre-placed attachments with high precision, thereby achieving accurate tooth movement control without excessive design complexity.
Solution Approach 2:
The patent implements local quality by concentrating precise geometric features and tight tolerances only in the regions where attachments are placed, while allowing more tolerance in other portions of the appliance. This localized precision approach achieves accurate attachment placement and tooth movement control without requiring the entire appliance to be manufactured with high precision, thereby reducing overall design complexity.
Data Source
AI summary
Methods for determining appliance geometry are provided. In some embodiments, a method includes determining a geometry for an attachment placement appliance. The attachment placement appliance can include an appliance body including a support formed in a tooth-receiving cavity for a tooth of a patient, one or more coupling structures connected to the support, and an aligner attachment connected to the one or more coupling structures. The aligner attachment can be configured to be mounted on the tooth and shaped to engage with an attachment well of a shell aligner and exert forces on the tooth when the aligner attachment is coupled to the attachment well. The appliance body can be configured to align an aligner attachment to a predetermined location on the tooth. The method can further include generating instructions for direct fabrication of the attachment placement appliance via an additive manufacturing process, based on the determined geometry.