Multilayer Dental Aligner with Hydrophobic Skin Layers
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Solution Overview
Problem
Conventional dental appliances face challenges in balancing durability, safety, and comfort, especially in high humidity environments like the oral cavity, where they need to provide consistent force over a long period without degrading rapidly.
Innovation Solution
A multilayer sheet structure for dental appliances is introduced, featuring a core layer with high tensile modulus and elongation at break, sandwiched between hydrophobic skin layers with specific water contact angles and surface energies, preventing water penetration and enhancing mechanical strength and durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If plastic materials with certain transmissivity are used to form aligners, then aesthetics and comfort are improved, but durability and mechanical strength deteriorate in high humidity environments
Solution Approach 1:
The patent employs a multilayer composite structure consisting of a core layer made from plastic material with visible light transmissivity (for aesthetics and comfort) and skin layers made from hydrophobic materials (for durability and water resistance). This composite structure allows the aligner to maintain both aesthetic properties and mechanical strength in the high humidity oral environment by preventing water penetration into the core layer.
Solution Approach 2:
Different layers of the aligner are assigned different properties: the core layer provides optical properties (transmissivity) for aesthetics, while the outer skin layers provide hydrophobicity and water resistance for durability. This local differentiation of material properties allows each layer to perform its specific function optimally, resolving the contradiction between aesthetics and durability.
2Ease of operation
If conventional plastic materials are used for dental appliances, then comfort and aesthetics are improved, but mechanical strength and durability worsen due to water-induced plasticization
Solution Approach 1:
The hydrophobic skin layers act as intermediary protective barriers between the oral environment (water/saliva) and the core plastic material. These skin layers prevent water from reaching and plasticizing the core material, thereby maintaining mechanical strength while allowing the core material to provide comfort and aesthetic properties.
Solution Approach 2:
The multilayer composite structure combines materials with complementary properties: the core layer provides comfort and aesthetics through its optical properties, while the hydrophobic skin layers provide protection against water-induced plasticization, maintaining overall mechanical strength.
3Strength
If metal materials are used for brackets and arch wires, then strength and durability are improved, but aesthetics deteriorate due to metallic color visibility
Solution Approach 1:
The patent creates a composite structure where the core layer made from translucent plastic material replaces traditional metal components, providing aesthetic advantages. The hydrophobic skin layers are added to maintain durability, thus achieving both aesthetics and strength without using visible metal materials.
4Device complexity
If single-layer plastic structures are used for dental appliances, then manufacturing simplicity is maintained, but reliability deteriorates due to rapid degradation in high humidity environments
Solution Approach 1:
The dental appliance is segmented into multiple functional layers: a core layer for structural integrity and aesthetics, and hydrophobic skin layers for environmental protection. This segmentation allows each layer to perform its specific function, improving overall reliability while maintaining manufacturing feasibility through established multilayer fabrication techniques.
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 multilayer structure improves the reliability and durability of dental appliances by maintaining mechanical strength and preventing water-induced plasticization, reducing the need for frequent appliance changes and minimizing unwanted side effects.
Implementation Method 1
a first skin layer and a second skin layer which are hydrophobic and can prevent water from penetrating into the core layer
Data Source
AI summary
A multilayer sheet for a dental appliance provided in the present disclosure includes a core layer having a tensile modulus greater than about 1400 MPa and an elongation at break greater than about 3%; and a first skin layer and a second skin layer sandwiching the core layer, wherein each of the first skin layer and the second skin layer independently has a water contact angle greater than 72° and/or a surface energy less than about 40 mN/m. The first skin layer and the second skin layer are the outermost layers of the multilayer sheet. A dental appliance made from the multilayer sheet structure is also provided.