Dual Shell Dental Appliance with Elastomeric Core
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Solution Overview
Problem
Current orthodontic and dental appliances face limitations in accurately moving teeth due to materials with limited elastic range, rapid decay of recovery force, and susceptibility to staining and environmental stress cracking, which affects their durability and comfort.
Innovation Solution
A polymeric sheet composition with two outer layers made of thermoplastic polymers and a middle elastomeric layer, providing a dual shell structure that allows for reversible deformation and improved stress resistance, while maintaining rigidity for precise tooth movement and resistance to staining.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If single layer or bi-layer materials are used for dental appliances, then manufacturing is simpler, but functionality and performance are limited
Solution Approach 1:
The patent employs a multi-layer composite structure consisting of an inner shell made from a first material and an outer shell made from a second material. Each material is selected to provide specific functional properties, such as flexibility, strength, stain resistance, and comfort. This composite approach allows the appliance to simultaneously achieve multiple performance requirements that cannot be met by single-layer or bi-layer constructions.
Solution Approach 2:
The dental appliance is divided into distinct functional layers: an inner shell portion that contacts the teeth and an outer shell portion that provides structural support and aesthetic appearance. Each layer can be optimized independently for its specific function, allowing the inner layer to focus on tooth engagement and force application while the outer layer handles durability and cosmetic requirements.
2Manufacturing precision
If rigid materials are used for dental appliances, then tooth movement precision is improved, but comfort and stress resistance deteriorate
Solution Approach 1:
The patent applies different material properties to different regions of the appliance. The inner shell portion is formulated with materials that provide flexibility and comfort for patient wear, while the outer shell portion uses materials optimized for precision and structural integrity. This local differentiation allows each region to perform its specific function optimally without compromising the other.
Solution Approach 2:
By combining materials with complementary properties in a multi-layer construction, the appliance achieves both rigidity for precise tooth movement control and flexibility for patient comfort. The inner layer can be made from softer, more compliant materials that adapt to tooth surfaces, while the outer layer provides the necessary stiffness for effective orthodontic force application.
3Ease of operation
If elastomeric materials are used for dental appliances, then flexibility and comfort are improved, but strength and rigidity deteriorate
Solution Approach 1:
The patent utilizes a composite structure where the inner shell portion can be made from elastomeric materials to provide flexibility, comfort, and stress distribution, while the outer shell portion is constructed from stronger, more rigid materials to maintain structural integrity and provide necessary mechanical strength. This division allows the appliance to exhibit both flexible and rigid characteristics in appropriate locations.
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 dual shell structure enhances the elastic properties and environmental stress cracking resistance of dental appliances, allowing for more effective tooth movement with reduced discomfort and increased durability, while maintaining stain resistance.
Implementation Method 1
the elastomeric inner layer can reversibly deform and dissipate impact forces
Implementation Method 2
The outer shell material may be a thermoplastic material that has been heated to a temperature above its melting point during forming
Data Source
AI summary
Improved dental appliances and polymeric sheet compositions are disclosed. The polymeric sheet compositions are useful for making dental appliances having outer layers comprised of a material having a modulus of from about 1,000 MPA to 2,500 MPA (“hard”) and an inner core comprised of elastomeric material or materials having a modulus of from about 50 MPa to 500 MPa (“soft”), which exhibit improved flexibility and strength, and better stain and tear resistance than currently available materials and dental appliances.