Programming Shape Memory Orthodontic Components via Intermediate Baking
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Solution Overview
Problem
Orthodontic components made of shape memory materials face unfavorable material behavior changes during severe bending, leading to plastic deformation and brittleness, which compromises their ability to exert the desired force in orthodontic appliances.
Innovation Solution
The process involves using intermediate baking molds to distribute severe bending across multiple stages, reducing the extent of bending in each step to avoid plastic deformation, with the target baking mold completing the final shape, thereby maintaining material integrity and effectiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If severe bending is applied to program orthodontic components from shape memory material into target shape, then the desired geometry is achieved, but plastic deformation and brittleness occur in the material
Solution Approach 1:
The severe bending process is divided into multiple sequential bending steps with intermediate annealing treatments. Each bending step applies a portion of the total deformation, followed by annealing to restore material properties before the next bending step. This segmentation prevents plastic deformation and brittleness while achieving the target geometry.
Solution Approach 2:
Annealing treatment is applied preliminarily before each bending step to restore the material's ductility and prevent plastic deformation. The intermediate annealing treatments prepare the material in advance for subsequent bending operations, ensuring material integrity throughout the programming process.
2Reliability
If intermediate baking molds are used to distribute bending across multiple stages, then material integrity is maintained, but the programming process complexity increases
Solution Approach 1:
Intermediate baking molds serve as intermediary tools that enable controlled, incremental bending of the orthodontic components. Each mold is designed to apply a specific portion of the total deformation, acting as a mediator between the initial straight state and the final target geometry. This intermediary approach maintains material integrity while achieving the desired shape.
3Reliability
If multiple bending steps are performed to avoid plastic deformation, then material behavior remains favorable, but the programming time increases
Solution Approach 1:
The programming process employs periodic alternating actions of bending and annealing. Each cycle consists of a bending step followed by an annealing step, repeating this pattern until the target geometry is achieved. This periodic action maintains favorable material behavior while systematically progressing toward the final shape, optimizing the balance between material integrity and programming time.
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 prevents plastic deformation and maintains the material's ability to exert force effectively, ensuring the orthodontic components can be programmed into target shapes without compromising their performance.
Implementation Method 1
The shape memory effect is based on a thermoelastic martensite transformation, a reversible phase transformation caused by shearing of the lattice planes. The cooling of the high-temperature phase, called austenite, below the alloy-specific martensite starting temperature leads to the phase transformation without shape change and without irreversible plastic deformation
Implementation Method 2
The heating above the alloy-specific austenite starting temperature then results in the recovery of the original shape
Implementation Method 3
Shape memory alloys are easily deformed in the martensitic state; the reversible deformation can be up to 8% for NiTi. This deformation is permanent as long as the alloy is in the martensitic state.
Data Source
AI summary
Process for programming an orthodontic component from a shape memory material starting from an initial shape of the orthodontic component into a target shape to be programmed of the orthodontic component, wherein the target shape compared to the initial shape at least sectionally has a severe bending, the process comprising the following steps:a. providing an orthodontic component (1) of a shape memory material in an initial shape,b. creating a target baking mold for the orthodontic component (1),c. inserting the orthodontic component (1) into the target baking mold, andd. baking the orthodontic component (1) in the target baking mold in order to program it into the target shape,characterized by the following steps after step a)e. creating at least one intermediate baking mold for the orthodontic component (1), in which intermediate baking mold the orthodontic component (1) has an intermediate shape between the initial shape and the target shape,f. inserting the orthodontic component (1) into the intermediate baking mold, andg. baking the orthodontic component (1) in the intermediate baking mold.