3D-Fabricated Attachment Placement Appliances for Accurate Tooth Alignment
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Solution Overview
Problem
Prior orthodontic appliances with homogeneous and continuous material properties lack control over forces applied to teeth, are sensitive to manufacturing tolerances, and have accuracy issues in tooth movement and attachment placement.
Innovation Solution
The development of orthodontic appliances with heterogeneous properties, featuring a stiff outer shell and a compliant inner structure, which allows for customized force and torque application to different subsets of teeth, and improved manufacturing methods for accurate placement of attachments using 3D scan data and direct fabrication techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If orthodontic appliances use homogeneous and continuous material properties, then manufacturing is simpler, but control over forces applied to teeth is insufficient
Solution Approach 1:
The patent applies local quality by creating regions of different material properties within the appliance. Specifically, it uses a stiff outer shell combined with a compliant inner structure, where the compliant regions have different stiffness characteristics than the stiff regions. This allows different parts of the appliance to exert different forces on different teeth, providing precise control over force application while maintaining manufacturability through additive manufacturing processes.
Solution Approach 2:
The patent employs composite materials by combining materials with different mechanical properties within a single appliance structure. The stiff outer shell is made from a first material while the inner structure uses a second material with different stiffness characteristics. This composite approach enables the appliance to simultaneously provide structural integrity and localized compliance for controlled force application.
2Strength
If orthodontic appliances are relatively stiff, then structural integrity is improved, but manufacturing tolerances must be tighter which increases complexity
Solution Approach 1:
The patent resolves this contradiction by creating local quality variations where stiff regions provide structural integrity while compliant regions accommodate manufacturing tolerances. The compliant inner structure can deform to compensate for tolerance variations, reducing the need for tight manufacturing tolerances overall while maintaining structural integrity in the stiff outer shell regions.
Solution Approach 2:
The patent applies parameter changes by varying the stiffness parameter across different regions of the appliance. The stiff outer shell maintains high stiffness for structural integrity, while the compliant inner structure has reduced stiffness to tolerate manufacturing variations. This gradient in stiffness parameters allows the appliance to be both strong and tolerant of manufacturing imperfections.
3Ease of manufacture
If orthodontic appliances use homogeneous material properties, then manufacturing is easier, but accuracy of tooth movement and attachment placement deteriorates
Solution Approach 1:
The patent improves tooth movement accuracy by implementing local quality with compliant inner structures that can precisely conform to individual tooth surfaces. These compliant regions adapt to the specific geometry of each tooth, ensuring accurate attachment placement and controlled tooth movement paths, while the overall appliance remains manufacturable through additive processes.
4Device complexity
If orthodontic appliances have continuous material properties, then structural simplicity is maintained, but control over forces applied to different subsets of teeth is reduced
Solution Approach 1:
The patent achieves force control over different teeth by implementing local quality with compliant inner structures at specific locations. These localized compliant regions can be independently configured to apply different forces to different teeth or tooth subsets, while the overall appliance structure remains relatively simple and integrated, manufactured as a single piece through additive manufacturing.
Data Source
AI summary
Methods for fabricating attachment placement appliances are provided. In some embodiments, a method includes directly fabricating an attachment placement appliance body including a support formed in a tooth-receiving cavity configured to receive a tooth. The method can include directly fabricating one or more coupling structures connected to the support, and directly fabricating an aligner attachment connected to the one or more coupling structures. The attachment placement appliance body can be configured to align the aligner attachment to a predetermined location on the tooth. The aligner attachment can be shaped to engage with an attachment well of a shell aligner and exert one or more forces on the tooth when the aligner attachment is coupled to the attachment well. The one or more coupling structures can be configured to release the aligner attachment with removal of the attachment placement appliance body from the tooth.