Clear Aligner Cavity Geometry for Precise Tooth Movement

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing methods for aligning teeth, such as braces and transparent shell appliances, often fail to achieve complex tooth movements efficiently and uniformly, leading to suboptimal results and user compliance issues.

Innovation Solution

The use of polymeric shell appliances configured to apply activation forces in directions opposite to intended tooth movement, utilizing differential moments and counter moments to control tooth movement, with engagement structures and cavities shaped to correspond to tooth profiles, and processed using 3D printing or thermoforming to enhance precision.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If transparent shell appliances are used to move teeth, then teeth can be moved to target positions, but the force applied to each tooth may not be ideal and movement may be insufficient

Engineering Contradiction:
Improvetooth movement precisionVSAvoidforce applied to tooth
Core Design Contradiction:
Measurement precisionVSForce

Solution Approach 1:

The appliance is segmented into multiple engagement structures, each applying force to specific teeth or groups of teeth. This allows differential force application where each tooth receives optimized force magnitude and direction tailored to its specific movement requirements, resolving the contradiction between achieving precise movement and applying ideal force.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different portions of the appliance have different geometric configurations to apply different forces to different teeth. The engagement structures are locally optimized with varying shapes, sizes, and orientations to provide site-specific force characteristics, enabling precise control of force application at each tooth location while achieving overall treatment goals.

Inventive Principle:
Principle #3Local quality

2Adaptability or versatility

If braces are used to move teeth, then complex tooth movements can be achieved, but braces are cumbersome to wear and require expertise to place

Engineering Contradiction:
Improvecomplex tooth movement capabilityVSAvoidease of wear and placement
Core Design Contradiction:
Adaptability or versatilityVSEase of operation

Solution Approach 1:

The invention uses a flexible polymeric shell appliance that covers the teeth rather than rigid brackets and wires. This thin film approach provides the versatility to achieve complex tooth movements through carefully designed engagement structures while being comfortable to wear and simple for patients to insert and remove themselves, eliminating the need for professional placement.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The appliance is designed to be self-applied by patients without professional assistance. The flexible shell can be easily inserted over the teeth and removed when needed, giving patients control over their own treatment process while the engineered engagement structures ensure complex movements are achieved through patient-compliant wear.

Inventive Principle:
Principle #25Self-service

3Measurement precision

If cavities are shaped to position tooth at final intended position, then tooth can be moved to target, but force applied decreases as tooth moves toward target and movement may not be uniform

Engineering Contradiction:
Improvetooth positioning accuracyVSAvoidforce application duration
Core Design Contradiction:
Measurement precisionVSDuration of action of moving object

Solution Approach 1:

The engagement structures are designed with dynamic geometric features that adapt as teeth move. The shapes incorporate cams, wedges, or other dynamic elements that automatically adjust force magnitude and direction during the movement process, maintaining optimal force levels throughout the entire treatment duration rather than force decreasing as the target is approached.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The appliance geometry is pre-configured to anticipate and compensate for force decay during tooth movement. By incorporating built-in mechanical advantage features and strategic engagement point locations in the initial design, the system maintains sufficient force application throughout the movement trajectory, ensuring uniform progress toward the target position.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP4729022A2Method to modify aligner by modifying tooth position
Publication Date: 2026.04.22 ALIGN TECHNOLOGY INC
  • EP4729022A2 patent drawingFigure 1A~1B
  • EP4729022A2 patent drawingFigure 2
  • EP4729022A2 patent drawingFigure 3A

AI summary

Polymeric shell appliances are provided in which the polymeric shell appliances are configured to provide one or more activation forces to facilitate tooth movement. In many embodiments, the activation forces are arranged to provide force in a direction opposite to an intended direction of tooth movement. The polymeric shell appliances may comprise one or more tooth receiving cavities, in which each of the plurality of tooth receiving cavities is shaped and arranged to provide a counter moment of each of the plurality of teeth.