Orthodontic Transfer Tray Geometry for Precise Bonding and Safe Release

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Solution Overview

Problem

The conventional process of creating transfer trays for orthodontic appliances is laborious and prone to human error, requiring manual positioning of brackets on replica models, which increases time and material costs, and can lead to bond failures during tray removal.

Innovation Solution

A method using rapid prototyping techniques to create customized transfer trays with virtual modeling, where the desired appliance locations are defined, and a gingival edge intersects each receptacle, allowing for precise positioning and easy engagement/disengagement, incorporating stop members and receptacles made from different materials for improved accuracy and ease of use.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional manual methods are used to create transfer trays, then customization for each patient is possible, but the process is laborious and prone to human error

Engineering Contradiction:
Improvepositioning accuracyVSAvoidmanufacturing time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The patent replaces manual mechanical positioning methods with an automated system that uses a digital model of the patient's dental arch and computer-controlled positioning mechanisms. The transfer tray is designed with features that automatically align with anatomical landmarks on the digital model, eliminating manual measurement and positioning errors while reducing the time required to create customized trays.

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

Solution Approach 2:

The invention changes the parameters of the transfer tray design by incorporating specific geometric features (such as intersecting gingival edges with receptacles) that are determined through computational analysis of the digital dental model. These parameter changes enable automatic positioning and reduce reliance on manual adjustment, thereby improving precision while maintaining efficiency.

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If the tray fully encapsulates appliances for secure retention, then positioning accuracy is improved, but tray removal becomes difficult and may cause bond failures

Engineering Contradiction:
Improveappliance positioningVSAvoidbond integrity
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The transfer tray is segmented into distinct functional zones: receptacles that fully encapsulate appliances for secure positioning, and gingival edges that intersect these receptacles to create controlled release points. This segmentation allows the tray to provide strong retention during bonding while enabling safe removal without compromising the bonded appliances.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the transfer tray have different encapsulation qualities. The receptacle regions provide full encapsulation for secure appliance retention, while the gingival edge regions provide partial encapsulation that facilitates tray removal. This local variation in quality allows the tray to simultaneously achieve secure positioning and safe removal.

Inventive Principle:
Principle #3Local quality

3Ease of manufacture

If uniform material is used for the entire tray, then manufacturing is simplified, but functional performance is compromised

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidtray performance
Core Design Contradiction:
Ease of manufactureVSEase of operation

Solution Approach 1:

The transfer tray is constructed as a composite structure with regions of different material properties or densities. The receptacle areas may use materials optimized for appliance retention, while the gingival edge areas use materials or structures optimized for easy removal. This composite approach maintains manufacturing feasibility while significantly improving overall tray performance.

Inventive Principle:
Principle #40Composite materials

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 reduces the risk of bond failures, minimizes adhesive smearing, and facilitates easy detachment of the tray without pulling on newly bonded appliances, enhancing the efficiency and consistency of the transfer tray manufacturing process.

Implementation Method 1

rapid prototyping techniques to form a physical transfer tray from the virtual transfer tray

Methodology Applied
Scientific EffectPhotopolymerisation: Photopolymerisation

Data Source

PatentEP3649981B1Rapid prototyped transfer tray for orthodontic appliances
Publication Date: 2023.09.06 SOLVENTUM INTELLECTUAL PROPERTIES CO
  • EP3649981B1 patent drawingFigure 1
  • EP3649981B1 patent drawingFigure 2~3
  • EP3649981B1 patent drawingFigure 4~5

AI summary

The present invention relates to a transfer tray for use in bonding of a plurality of orthodontic appliances, each having a base for bonding to a tooth surface and a body extending outwardly from the base, the tray comprising a plurality of receptacles for the plurality of orthodontic appliances, each of the plurality of receptacles having a configuration matching a portion of the appliance body to releasably retain the appliance, the plurality of orthodontic appliances releasably retained in the plurality of receptacles, and a tray body extending continuously across the plurality of receptacles and having a gingival edge, wherein the gingival edge intersects each of the plurality of receptacles such that a first portion of each appliance body extends below the gingival edge and is not enclosed by any portion of the tray body for each appliance releasably retained in each receptacle, and wherein each receptacle and the tray body cooperate to cover all exterior surfaces of each appliance body opposite the base and located in an occlusal direction from the gingival edge for each appliance releasably retained in each receptacle, wherein prior to placement of the appliances on the teeth while the appliance are retained in the receptacles of the tray body, positions of the receptacles in the tray body correspond with positions of teeth to receive the appliances retained in the receptacles.