Interproximal Aligner Structures for Precise Tooth Rotation Control

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Solution Overview

Problem

Existing tooth-moving methods using transparent shell appliances are less than ideal due to the cumbersome nature of attachments on the teeth, which can complicate patient use.

Innovation Solution

The use of interproximal engagement structures that extend into the interproximal space of teeth to provide more accurate tooth movement, allowing for improved anchoring and control of tooth rotation, with the structures being designed based on 3D profile data of the patient's mouth and directly fabricated to fit the treatment plan.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If attachments are used on teeth to engage the appliance for complex tooth movements, then tooth movement effectiveness is improved, but patient comfort and ease of operation deteriorate due to cumbersome attachments

Engineering Contradiction:
Improvetooth movement effectivenessVSAvoidpatient comfort
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent removes attachments from the teeth and relocates the engagement functionality to the appliance itself through interproximal engagement structures. These structures extend into the interproximal spaces between teeth, providing the necessary mechanical engagement for complex tooth movements without requiring attachments on the teeth, thereby maintaining effectiveness while improving patient comfort.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The engagement mechanism transitions from a vertical attachment on the tooth surface to a horizontal interproximal engagement between teeth. By utilizing the interproximal dimension (the space between adjacent teeth), the appliance achieves complex tooth movement control without adding vertical attachments that would compromise patient comfort.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Ease of operation

If traditional transparent shell appliances are used without interproximal engagement structures, then patient comfort is maintained, but tooth movement precision and anchoring capability are insufficient

Engineering Contradiction:
Improvepatient comfortVSAvoidtooth movement precision
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The appliance is segmented with discrete interproximal engagement structures that can be independently positioned and sized. These structures are distributed across multiple interproximal spaces, allowing precise control of individual tooth movements while maintaining overall appliance integrity and patient comfort.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The interproximal engagement structures are specifically designed with varying lengths, positions, and engagement depths tailored to each interproximal space and target tooth movement requirement. This localized customization enables precise tooth movement control in specific areas while maintaining comfort in other regions.

Inventive Principle:
Principle #3Local quality

3Ease of operation

If fewer attachments are used on teeth, then patient comfort is improved, but the ability to control complex tooth movements and anchoring is reduced

Engineering Contradiction:
Improvepatient comfortVSAvoidcontrol capability
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The interproximal engagement structures serve multiple functions simultaneously: they provide anchoring against adjacent teeth, generate rotational moments through offset engagement, control tooth position, and distribute forces across multiple teeth. This multi-functionality replaces the need for multiple separate attachments while improving patient comfort.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent combines the anchoring function, rotational control function, and position control function into a single integrated interproximal engagement structure. By merging these functions that would traditionally require separate attachments, the appliance achieves complex tooth movement control with fewer components, improving comfort while maintaining capability.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP4233779B1Direct fabrication of aligners with interproximal force coupling
Publication Date: 2026.01.14 ALIGN TECHNOLOGY INC
  • EP4233779B1 patent drawingFigure 1A
  • EP4233779B1 patent drawingFigure 1B
  • EP4233779B1 patent drawingFigure 1C

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 appliances comprise interproximal engagement structures to provide activation forces to interproximal tooth surfaces. In many embodiments, the activation forces are arranged to provide a plurality of forces, including a 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.