Multilayer Dental Aligner with Elastomeric Core for Tooth Movement
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current clear aligner therapies are limited by the maximum tooth movement per stage, typically around 0.3 mm, due to stress/strain properties of plastics and biomechanics of tooth movement, leading to discomfort, potential damage, and inaccurate movements.
Innovation Solution
The use of multilayer aligner structures with at least two outer layers and an elastomeric inner layer, where the elastomeric layer has a thickness of greater than 250 microns up to 1,000 microns and a hardness of Shore A80 to Shore D65, allows for increased tooth movement per stage without causing pain or root damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional plastic materials (polyester, rigid polyurethane) are used for aligners, then the aligners provide sufficient structural strength, but the tooth movement per stage is limited to about 0.3 mm due to stress/strain properties
Solution Approach 1:
The patent applies composite materials by combining a rigid outer layer (polyester or polyurethane) with an elastomeric inner layer (thermoplastic elastomer or rubber). This composite structure allows the aligner to provide both structural strength for comfort and sufficient elasticity to achieve greater tooth movement (0.4-0.8 mm per stage) without causing pain or root damage, resolving the contradiction between movement precision and movement rate.
Solution Approach 2:
The patent changes the material parameters by introducing an elastomeric layer with specific properties (Shore hardness A80-D65, thickness 250-1000 microns) that modifies the stress/strain characteristics of the aligner. This parameter change enables the material to withstand higher deformation forces while remaining comfortable, thereby increasing the effective tooth movement per stage beyond the traditional 0.3 mm limit.
2Loss of time
If greater tooth movement per stage is attempted (beyond 0.3 mm), then the treatment time is reduced, but it causes discomfort to the patient and may damage tooth roots or jaw bone
Solution Approach 1:
The composite structure of rigid outer layer plus elastomeric inner layer allows the aligner to deliver greater tooth movement (0.4-0.8 mm per stage) while distributing forces more evenly. The elastomeric layer acts as a cushion that reduces peak stresses on tooth roots and surrounding bone, thereby reducing patient discomfort and damage risk even at higher movement rates.
Solution Approach 2:
The elastomeric inner layer serves as a beforehand cushioning element that prevents excessive stress concentration on tooth roots and jaw bone during rapid tooth movement. This cushioning layer absorbs and distributes forces that would otherwise cause discomfort or damage, enabling safer high-speed tooth movement.
3Productivity
If greater tooth movement per stage is programmed, then fewer aligners are needed, but the actual movement becomes inaccurate due to biomechanical limitations
Solution Approach 1:
The composite material structure enables the aligner to achieve both high movement efficiency (0.4-0.8 mm per stage) and high accuracy by combining the structural integrity of rigid materials with the elastic recovery properties of elastomers. This ensures that the planned tooth movements are precisely achieved without the inaccuracies that occur with single-material systems attempting greater movements.
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
This approach enables a reduction in the number of aligners required, allows for a greater range of tooth movement per stage, and improves the predictability of tooth movement, reducing material usage and fabrication time.
Implementation Method 1
at least one elastomeric inner layer, wherein the elastomeric inner layer has a thickness of greater than 250 microns up to about 1,000 microns, and a hardness of from about Shore A80 to Shore D 65
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 3,000 MPA (“hard”) and an inner core comprised of elastomeric material or materials having a modulus of from about 25 MPa to 500 MPa (“soft”) and a thickness of greater than about 250 microns, which exhibit improved flexibility and strength, and better stain and tear resistance than currently available materials and dental appliances.