3D Printed Orthodontic Aligner Layer Orientation for Trace-Free Front Teeth

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Solution Overview

Problem

Existing 3D printed mouthpieces often form annular lamination traces on the buccal surface of front teeth, which affect aesthetics and cause discomfort due to light diffraction, impacting the quality of life by degrading the appearance of the front teeth portion.

Innovation Solution

Manufacturing mouthpieces using an additive manufacturing device to laminate hardened layers at specific angles, such as 0 to 60° or 120 to 240° relative to the occlusal plane, to prevent annular lamination traces on the buccal surface of front teeth.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the mouthpiece is manufactured by conventional additive manufacturing without controlling lamination direction, then the manufacturing process is simple and fast, but annular lamination traces are formed on the buccal surface of front teeth, degrading aesthetics

Engineering Contradiction:
Improveaesthetic quality of front teeth portionVSAvoidmanufacturing process complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies different lamination directions to different regions of the mouthpiece. Specifically, the buccal surface of front teeth is manufactured with lamination directions that prevent annular traces, while other regions can use standard lamination patterns. This localized control of manufacturing parameters resolves the contradiction by improving aesthetic quality in critical areas without requiring complete redesign of the entire manufacturing process.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent changes the lamination direction parameter during the additive manufacturing process. By adjusting the orientation of deposited layers in specific regions (particularly avoiding horizontal lamination on buccal surfaces), the method prevents annular trace formation. This parameter modification allows maintaining manufacturing efficiency while improving aesthetic outcomes in visible areas.

Inventive Principle:
Principle #35Parameter changes

2Ease of manufacture

If annular lamination traces are formed on the buccal surface of front teeth, then the manufacturing process remains unchanged, but light diffraction occurs causing discomfort and reduced quality of life

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidlight diffraction and discomfort
Core Design Contradiction:
Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The patent implements region-specific lamination control where only the buccal surfaces of front teeth receive special attention regarding lamination direction. Other regions of the mouthpiece can maintain standard manufacturing patterns. This selective approach reduces light diffraction in visible areas while preserving manufacturing simplicity overall.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent converts the potential harm of visible lamination traces into a benefit by strategically orienting layers to create more favorable trace patterns. Instead of trying to eliminate all lamination effects, the method utilizes the lamination structure itself to create patterns that are less visually disruptive and reduce unwanted light diffraction in aesthetic regions.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

3Manufacturing precision

If the lamination direction is optimized to prevent annular traces on front teeth, then aesthetics are improved, but the manufacturing process becomes more complex

Engineering Contradiction:
Improvesurface quality of buccal portionVSAvoidmanufacturing efficiency
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The patent implements selective lamination control only in regions requiring high aesthetic quality (buccal surfaces of front teeth), while allowing standard manufacturing processes to continue for less visible areas. This localized precision approach maintains overall manufacturing efficiency while achieving superior surface quality where it matters most.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent applies partial optimization to the lamination process, focusing enhancement efforts only on critical aesthetic regions rather than the entire mouthpiece. This partial action approach achieves sufficient aesthetic improvement without the excessive complexity that would result from optimizing all surfaces equally, thereby preserving manufacturing productivity.

Inventive Principle:
Principle #16Partial or excessive action

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

Prevents annular lamination traces on the buccal surface of front teeth, improving aesthetics and reducing discomfort when worn, while maintaining structural integrity and enhancing the mouthpiece's strength and durability.

Implementation Method 1

manufacturing the mouthpiece that is to be placed within an oral cavity to cover teeth by an additive manufacturing device

Methodology Applied
Scientific EffectAdditive manufacturing: 3D Printing

Implementation Method 2

laminating hardened layers not to form an annular lamination trace in a buccal portion that covers a buccal surface of a front tooth

Methodology Applied
Scientific EffectLamination: Lamination

Data Source

PatentEP3984496B1Mouthpiece and mouthpiece manufacturing method
Publication Date: 2026.03.25 KURARAY NORITAKE DENTAL
  • EP3984496B1 patent drawingFigure 1
  • EP3984496B1 patent drawingFigure 2
  • EP3984496B1 patent drawingFigure 3

AI summary

To provide a mouthpiece and a method for manufacturing the mouthpiece that can prevent the formation of an annular lamination trace in a front teeth portion. A method for manufacturing a mouthpiece (orthodontic aligner (20)) includes manufacturing the mouthpiece that is to be placed within an oral cavity to cover teeth by an additive manufacturing device (30) and laminating hardened layers not to form an annular lamination trace in a buccal portion (22) that covers a buccal surface (12) of a front tooth (central incisor (10a), lateral incisors 10b, canine teeth 10c)).