Shape Memory Alloy Injection Tip for Root Canal Access
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Solution Overview
Problem
Conventional intraoral injection devices struggle to reach the most apical part of root canals and are inflexible, making it difficult to achieve homogeneous filling with fluid phase materials while minimizing air bubbles and accommodating varying tooth positions.
Innovation Solution
An injection device with a shape-memory metal tip that can be bent to adapt to the canal configuration, combined with a cylindrical design and circular ribs for secure locking and rotational freedom, allowing precise orientation and access to the entire canal housing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a conventional intraoral injection tip is used, then the device structure is simple, but the tip cannot reach the most apical part of the canal housing and cannot adapt to varying tooth positions
Solution Approach 1:
The injection tip is made from a shape memory alloy that can change its physical state between austenite (rigid) and martensite (flexible) phases. By controlling the temperature or stress applied to the tip, it transitions from a flexible state during insertion to a rigid state for stable injection, enabling both apical access and operational stability without increasing structural complexity
Solution Approach 2:
The injection tip transforms from a static, rigid structure to a dynamic, adaptable structure. The shape memory effect allows the tip to dynamically adjust its shape and rigidity based on the operational requirements - flexible during navigation to reach apical regions, then rigid during injection to maintain position and deliver material effectively
2Adaptability or versatility
If a rigid injection tip is used, then the tip maintains stable orientation, but it cannot be bent to adapt to the canal configuration and tooth positions
Solution Approach 1:
The shape memory alloy tip allows controlled changes in orientation and rigidity by altering physical parameters such as temperature or applied stress. The tip can be softened to bend into the desired orientation, then hardened to maintain that orientation stably during the injection process, resolving the contradiction between adaptability and stability
Solution Approach 2:
The tip is pre-programmed with a memory of its original shape. During use, it can be temporarily deformed to adapt to the canal configuration, but the pre-stored shape memory ensures it returns to or maintains the correct orientation and stability once the deformation force is removed, providing both adaptability and reliability
3Ease of operation
If the injection tip outer diameter is reduced to reach apical regions, then access to the canal is improved, but the structural strength of the tip is reduced
Solution Approach 1:
The shape memory alloy enables the tip to have high strength when needed (in the austenite phase) while maintaining a small diameter for canal access. The material's phase transition capability allows the thin-walled tip to become sufficiently strong during the injection process, overcoming the strength limitations that would normally accompany reduced diameter
4Adaptability or versatility
If a flexible injection tip is used, then the tip can adapt to canal configuration, but it cannot maintain stable orientation during injection
Solution Approach 1:
The injection tip dynamically transitions from a flexible, adaptable state during insertion to a rigid, stable state during injection. This temporal separation of properties allows the tip to first adapt to the canal configuration with flexibility, then maintain precise orientation and position stability during the injection process to ensure accurate filling
Solution Approach 2:
By changing the physical state of the shape memory alloy from martensite (flexible) to austenite (rigid), the tip transitions from an adaptable configuration to a stable, precision-maintaining state. This parameter change ensures that once the tip is positioned correctly, it maintains that position with sufficient rigidity to deliver the filling material precisely
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
Enables complete filling of root canals with minimal air bubbles and easy access to the apical region, improving the practitioner's ability to conform the tip to the tooth's anatomy, thus enhancing filling precision and ease of use.
Implementation Method 1
the injection tip is made of a material with shape memory so as to be able to bend it according to a desired orientation
Data Source
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AI summary
The invention relates to a device for injecting a filling material in the fluid phase into a canal space, the said device comprising an adaptor, an automatic mixer connected to the said adaptor, an intra-oral injection tip fitted at the upper end of the said automatic mixer, and is characterized in that the said injection tip is a tube the distal end of which has an outside diameter smaller than or equal to 1.5 mm over a length greater than or equal to 8 mm, in that the said injection tip is made of a shape memory material so that it can be bent to a desired orientation, in that the said injection tip is moulded at the upper end of the said automatic mixer, and in that the said injection tip comprises, on its exterior surface: either circular ribs defining a groove, the upper end of the automatic mixer being moulded into this groove so that the said injection tip is locked in position in the said upper end while at the same time retaining a degree of freedom to rotate about its axis of symmetry, or one or more mutually parallel circular ribs, the upper end of the automatic mixer being moulded onto this circular rib in such a way that the said injection tip is blocked in position in the said upper end while at the same time retaining a degree of freedom to rotate about its axis of symmetry.