Orthodontic Aligner Trimline Modeling for Precise Automated Trimming

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Solution Overview

Problem

Current methods for manufacturing orthodontic aligners face challenges such as complex trimming processes, spatial limitations in CNC milling, and the need for manual modifications, which are time-consuming and often compromise the design, leading to suboptimal performance and prolonged treatment.

Innovation Solution

A computer-implemented method and system for defining a trimline in a 3-D digital model of teeth, generating machine code for manufacturing aligners, and using CNC machinery to produce edges that correlate with the trimline, reducing the need for manual modifications and improving the accuracy and efficiency of aligner production.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If manual trimming with scissors is used, then the aligner can be trimmed to fit complex shapes, but the process is time-consuming and requires significant skill

Engineering Contradiction:
Improvetrimming precisionVSAvoidtrimming time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The patent replaces manual mechanical trimming with an automated laser trimming system. The laser trimming device uses optical energy to precisely cut the aligner material according to digital trimline specifications, eliminating the need for manual scissor trimming while maintaining high precision and significantly reducing time requirements.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the trimming method from mechanical cutting to laser-based optical cutting. By using laser energy with controlled parameters (power, speed, focal point), the system achieves precise trimming of complex aligner shapes without the time and skill constraints of manual methods.

Inventive Principle:
Principle #35Parameter changes

2Extent of automation

If CNC milling machine is used for trimming, then automation is achieved, but the setup procedure is complicated and expensive

Engineering Contradiction:
Improvetrimming automationVSAvoidsetup complexity
Core Design Contradiction:
Extent of automationVSDevice complexity

Solution Approach 1:

The patent replaces the complex mechanical CNC milling system with a laser trimming device. The laser system uses digital modeling and optical guidance to automatically trim aligners based on trimline specifications, achieving automation without the complicated mechanical setup and tooling required by CNC milling machines.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent uses digital 3-D models and digital trimline specifications as copies of the desired final shape. These digital copies guide the laser trimming process, eliminating the need for physical fixtures, tooling, and complex mechanical setups that characterize traditional CNC milling operations.

Inventive Principle:
Principle #26Copying

3Productivity

If CNC milling is used for trimming, then some aligners can be separated automatically, but spatial limitations prevent complete separation of certain aligners

Engineering Contradiction:
Improveseparation efficiencyVSAvoidspatial adaptability
Core Design Contradiction:
ProductivityVSAdaptability or versatility

Solution Approach 1:

The patent transitions from 3-axis mechanical CNC milling to laser trimming that can operate in additional spatial dimensions. The laser beam can access and trim complex geometries, interproximal regions, and attachments from multiple angles without the spatial constraints of mechanical toolpaths, enabling complete separation of all aligner types including those with complex features.

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

Solution Approach 2:

The patent replaces the mechanically constrained CNC milling system with a laser trimming system that has superior spatial adaptability. The laser beam can precisely trim aligners with attachments, buttons, and complex geometries without the tool access limitations that prevent complete separation in CNC milling operations.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

4Adaptability or versatility

If manual field modifications are made to aligners, then clinician preferences can be accommodated, but the aligner performance is compromised and treatment is prolonged

Engineering Contradiction:
Improvecustomization flexibilityVSAvoidaligner performance
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent performs all necessary trimming and customization operations during the manufacturing process using automated laser trimming guided by digital models. Clinician preferences and customizations are incorporated into the digital trimline design before manufacturing, eliminating the need for post-manufacturing manual modifications that compromise aligner performance and extend treatment time.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3870097B1Systems and methods for designing and manufacturing an orthodontic appliance
Publication Date: 2024.03.20 ORMCO CORP
  • EP3870097B1 patent drawingFigure 1
  • EP3870097B1 patent drawingFigure 1A
  • EP3870097B1 patent drawingFigure 2

AI summary

Systems and methods of defining a trimline in relation to modeled teeth including modeled gingiva. The trimline is for use to manufacture an aligner. A margin point is placed proximate a gingival margin at each tooth on at least one jaw in the model. A trimline connects the plurality of margin points from which machine code is generated. The aligner manufactured includes an edge that correlates with the trimline according to the machine code. A margin point may be proximate a gingival zenith. At least one tooth cooperates with the modeled gingiva to define a line around the tooth. The trimline includes at least one tooth curve and at least one connector curve connected to the tooth curve at a transition point. At least one control point is on the trimline between two margin points. The trimline is defined by a spline that may be a Bèzier curve.