Virtual Dentition Model for Dental Retainer Fabrication

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Solution Overview

Problem

The existing methods for fabricating dental retainers are hindered by the difficulty of taking impressions of teeth while wearing braces, leading to distortion and increased costs due to manual removal of orthodontic appliances from plaster models, which is subjective and time-consuming.

Innovation Solution

A method using digital data to create a virtual dentition model by removing orthodontic appliances from digital data files, allowing for the production of a physical model without braces, facilitating the fabrication of dental retainers with improved accuracy and reduced fabrication time.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of time

If an impression of the patient's teeth while wearing braces is taken to fabricate a retainer in advance, then the retainer can be ready immediately after braces removal, but the impression material distorts and fractures in areas adjacent to orthodontic appliances, causing distortion of the stone model

Engineering Contradiction:
Improvetime to prepare retainerVSAvoidaccuracy of stone model
Core Design Contradiction:
Loss of timeVSManufacturing precision

Solution Approach 1:

The patent creates a digital copy (3D digital model) of the patient's dentition instead of using physical impressions and stone models. This digital copying process avoids the distortion and fracture problems associated with physical impression materials interacting with orthodontic appliances, while enabling rapid retainer fabrication.

Inventive Principle:
Principle #26Copying

Solution Approach 2:

The patent replaces the mechanical impression-taking process (using impression materials and stone models) with a digital scanning and modeling system. This substitution eliminates the mechanical interaction between impression material and orthodontic appliances that causes distortion, while maintaining the ability to create accurate models for retainer fabrication.

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

2Ease of manufacture

If manual removal of orthodontic appliances from stone models is performed to create a clean tooth model, then a usable model for retainer fabrication can be obtained, but the process is tedious, increases cost, and requires subjective estimation of missing surface contours

Engineering Contradiction:
Improveease of model preparationVSAvoidaccuracy of tooth surface contour
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent captures the complete tooth surface geometry digitally before any removal processes, creating an accurate digital copy that includes areas obscured by orthodontic appliances. This eliminates the need for subjective estimation of missing contours, as the digital scan records all surfaces directly.

Inventive Principle:
Principle #26Copying

Solution Approach 2:

The patent digitally extracts and removes the orthodontic appliance data from the digital model, automatically separating the appliance geometry from the tooth geometry. This automated extraction eliminates the need for manual removal and subjective estimation, providing objective and precise tooth surface contours.

Inventive Principle:
Principle #2Taking out (Extraction)

3Productivity

If digital data is used to create a virtual dentition model by removing orthodontic appliances, then fabrication time and costs are reduced with improved accuracy, but additional digital processing steps are required

Engineering Contradiction:
Improvespeed of retainer productionVSAvoidcomplexity of digital processing system
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent creates a digital copy of the dentition that can be easily manipulated and processed. This digital copying enables rapid iteration and processing without the physical manipulation required by stone models, significantly improving productivity despite the added digital processing steps.

Inventive Principle:
Principle #26Copying

Data Source

PatentEP2242441B1Methods of preparing a virtual dentition model and fabricating a dental retainer therefrom
Publication Date: 2019.01.23 3M INNOVATIVE PROPERTIES CO
  • EP2242441B1 patent drawingFigure 1~2
  • EP2242441B1 patent drawingFigure 3
  • EP2242441B1 patent drawingFigure 4~5

AI summary

A virtual model of a dental patient's dentition is provided by obtaining a digital data file of the patient's teeth and orthodontic appliances connected to the teeth, and then combining data from the data file with other data that represents surfaces of the teeth underlying the appliances. The virtual model is useful in preparing a physical model of the patient's current dentition that can be used, for example, to make a dental retainer. Advantageously, the retainer can be fabricated before the orthodontic appliances are disconnected from the patient's teeth and ready for use as soon as the patient's teeth have reached their desired positions in the oral cavity