Dual-Material Upper Retainer for Arch Expansion Stability

Solution Overview

Problem

Existing orthodontic retainers, such as Hawley and vacuum-formed retainers, fail to effectively maintain upper arch expansion and provide sufficient rigidity and retention, leading to potential relapse of teeth alignment post-treatment.

Innovation Solution

A dual-material orthodontic retainer is designed with a first material covering the buccal, occlusal, and lingual surfaces and a second material covering the palatal surface, featuring holes and bulges for bonding, using polyethylene and methyl methacrylate to enhance stability and strength.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Shape

If a vacuum-formed retainer is used to maintain aesthetic appearance, then the aesthetic appearance is improved, but the rigidity to maintain upper arch expansion deteriorates

Engineering Contradiction:

Improveaesthetic appearanceVSAvoidrigidity to maintain upper arch expansion

Core Design Contradiction:

ShapeVSStrength

Solution Approach 1:

The retainer combines a transparent thermoplastic material (for aesthetic appearance) with an acrylic baseplate (for rigidity and palatal coverage) to simultaneously achieve both aesthetic appearance and structural strength for maintaining upper arch expansion

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The retainer is divided into two distinct material components: a transparent thermoplastic portion covering the buccal surfaces for aesthetics and an acrylic baseplate providing structural support and palatal coverage, allowing each material to fulfill its optimal function

Inventive Principle:

Principle #1Segmentation

2Strength

If a Hawley retainer is used to maintain upper arch expansion, then the rigidity to maintain expansion is improved, but the aesthetic appearance deteriorates due to metal wires

Engineering Contradiction:

Improverigidity to maintain upper arch expansionVSAvoidaesthetic appearance

Core Design Contradiction:

StrengthVSShape

Solution Approach 1:

The retainer combines a transparent thermoplastic material (for aesthetic appearance) with an acrylic baseplate (for rigidity and palatal coverage) to simultaneously achieve both aesthetic appearance and structural strength for maintaining upper arch expansion

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The metal wire components are removed from the retainer design, replacing them with a transparent thermoplastic material that provides necessary structural support while eliminating the aesthetic disadvantage of visible metal wires

Inventive Principle:

Principle #2Taking out (Extraction)

3Stability of the object's composition

If a Hawley retainer is used, then the ability to maintain upper arch expansion is improved, but the retention of lower incisors deteriorates

Engineering Contradiction:

Improveupper arch expansion maintenanceVSAvoidretention of lower incisors

Core Design Contradiction:

Stability of the object's compositionVSReliability

Solution Approach 1:

The retainer is divided into two distinct material components: a transparent thermoplastic portion covering the buccal surfaces for aesthetics and an acrylic baseplate providing structural support and palatal coverage, allowing each material to fulfill its optimal function

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The retainer combines a transparent thermoplastic material (for aesthetic appearance) with an acrylic baseplate (for rigidity and palatal coverage) to simultaneously achieve both aesthetic appearance and structural strength for maintaining upper arch expansion

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

The retainer maintains upper arch expansion, improves retention, and enhances strength against breakage while maintaining an aesthetically pleasing appearance.

Implementation Method 1

After the second material is applied, it can then be cured to form a bond with the first material

Methodology Applied

Scientific EffectCuring:

Implementation Method 2

vacuum forming a first material over the cast of the teeth

Methodology Applied

Scientific EffectVacuum forming:

Data Source

PatentUS12594146B2Upper expansion orthodontic retainer

Publication Date: 2026.04.07 KING SAUD UNIVERSITY

AI summary

An orthodontic retainer includes a first material forming a contact surface for the buccal, occlusal, labial, and lingual surfaces of the maxillary teeth. The first material has a number of holes formed bi-laterally in the lingual surface. The orthodontic retainer includes a second material forming a contact surface for the palatal portion of the upper arch dentition. The second material is formed with several bulges that mate with corresponding holes within the first material. A method of forming the orthodontic retainer includes casting an impression, vacuum forming a first material over the cast of the teeth, trimming the first material in proximity to the gingival contours, drilling a number of holes in a lingual surface of the first material, applying a second material to the palatal portion of the cast and the holes of the first material, and curing the second material to the first material.