Heat-Treated NiTi Endodontic Instruments for Canal Navigation
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Solution Overview
Problem
Existing medical instruments, particularly endodontic and orthodontic instruments, face issues such as lateral transportation in curved canals, difficulty in enlarging curvilinear canals while maintaining the original center axis, and binding or 'screwing in' during procedures, due to their metallurgical and behavioral properties.
Innovation Solution
A method involving heat treatment of medical instruments made from superelastic alloys, specifically nickel-titanium, in a heated environment between 450°C to 550°C for 90 to 300 minutes, followed by natural cooling, to modify their memory characteristics and improve flexibility, torque, and cyclical fatigue resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If medical instruments are made from superelastic alloy to improve flexibility, then they can better navigate curved canals, but they exhibit undesired lateral transportation and binding in curved canals
Solution Approach 1:
The patent applies heat treatment at specific temperatures (450-550°C for 90-300 minutes) to modify the metallurgical properties of the superelastic alloy. This changes the material parameters to achieve optimal balance between flexibility and lateral force control, resolving the contradiction by tuning the alloy's behavioral properties through controlled thermal processing
2Ease of operation
If medical instruments are made from superelastic alloy to improve flexibility, then they can navigate curved canals, but they bind or screw in during procedures
Solution Approach 1:
Heat treatment modifies the metallurgical properties of the superelastic alloy to control its interaction with canal walls. The thermal processing changes material parameters that govern friction and engagement characteristics, reducing harmful binding and screwing-in effects while preserving necessary flexibility
3Ease of operation
If medical instruments are made from superelastic alloy to improve flexibility, then they can follow canal curvature, but they have difficulty enlarging curvilinear canals while maintaining original center axis
Solution Approach 1:
The heat treatment process modifies the superelastic alloy's metallurgical properties to optimize the balance between following canal curvature and maintaining center axis. The thermal processing adjusts material parameters that control instrument behavior during enlargement procedures
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 heat-treated instruments exhibit enhanced flexibility, reduced lateral forces, and increased cyclical fatigue resistance, allowing them to more accurately follow the natural root canal shape and endure more stress before failing, thus improving the efficiency and longevity of endodontic procedures.
Implementation Method 1
placing a medical instrument in a heated environment having a temperature of from about 450° C. to about 550° C. for from about 90 minutes to about 300 minutes
Implementation Method 2
the instrument, after being exposed to the heated environment, is preferably allowed to cool using natural heat transfer mechanisms in ambient air
Implementation Method 3
the medical instrument is made from at least about 50% by mass of a superelastic alloy
Implementation Method 4
the instrument undergoes a machining step to form a working portion prior to placing the endodontic instrument in the heated environment
Data Source
AI summary
Medical instruments, particularly, endodontic instruments with unique limited memory characteristics, and methods for making such instruments. One embodiment includes heat treating a finished endodontic instrument. A related embodiment includes electropolishing a finished endodontic instrument and then heat treating the endodontic instrument.