Endodontic Instrument Assembly With Triangular Flats for Easy Locking
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Solution Overview
Problem
Endodontic instruments face challenges with large, costly, and complex handles that obstruct visibility and require trial-and-error insertion, leading to increased production costs and difficulty in machining and assembly.
Innovation Solution
An endodontic instrument with a smaller assembly portion featuring three flats conforming to an equilateral triangle on its cross-section, allowing for centering, retention, and rotational drive, which can be machined easily and inserted in multiple angular positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional endodontic instrument with separate shaft and handle components is assembled, then the instrument can be manufactured and sterilized, but the assembly creates potential pathways for bacterial contamination and increases the risk of assembly/disassembly errors
Solution Approach 1:
The patent merges the shaft and handle components into a single monoblock structure manufactured from a single piece of memory alloy material. This eliminates the interface between components that could serve as bacterial contamination pathways, directly resolving the reliability issue while reducing the total component count to address the complexity concern.
Solution Approach 2:
While appearing to contradict segmentation, the patent actually applies it in reverse by eliminating segmentations. The traditional segmented design with multiple assembled parts is replaced with a unified monoblock structure, removing the assembly interface that creates contamination risks.
2Adaptability or versatility
If a traditional endodontic instrument with conventional materials is used, then the instrument can be manufactured with existing processes, but the instrument lacks shape memory properties and superelasticity required for navigating curved root canals
Solution Approach 1:
The patent changes the material parameters by selecting a specific nickel-titanium alloy composition with controlled ratios of nickel (50-70 wt%), titanium (20-45 wt%), and palladium (5-20 wt%). This compositional parameter change enables the desired shape memory and superelastic properties while maintaining manufacturability through established arc melting and investment casting processes.
Solution Approach 2:
The patent employs a composite alloy system combining nickel, titanium, and palladium in specific proportions. This composite material provides the unique combination of shape memory, superelasticity, and corrosion resistance required for endodontic applications, overcoming the limitations of conventional single-element or simple alloy materials.
3Reliability
If a traditional endodontic instrument is sterilized using conventional methods, then the instrument can be disinfected, but the assembly portions may become loose or damaged during repeated sterilization cycles
Solution Approach 1:
The patent combines the shaft and handle into a single monoblock structure that cannot become loose or damaged at assembly interfaces. This eliminates the specific vulnerability of assembly portions to sterilization damage while maintaining the instrument's ability to withstand repeated autoclaving cycles.
Solution Approach 2:
The patent designs the monoblock structure to inherently resist sterilization damage before exposure occurs. By eliminating assembly portions entirely, the design preemptively protects against the weakness point that would otherwise require reinforcement or special handling procedures.
4Reliability
If an endodontic instrument is designed with a monoblock structure, then assembly errors and bacterial contamination pathways are eliminated, but the manufacturing precision requirements increase
Solution Approach 1:
The patent achieves the required manufacturing precision by carefully controlling the alloy composition parameters (nickel 50-70 wt%, titanium 20-45 wt%, palladium 5-20 wt%) and processing parameters during arc melting and investment casting. These parameter controls enable reproduction of the complex monoblock geometry with sufficient precision for clinical use.
Solution Approach 2:
The patent applies local quality by optimizing the alloy composition and microstructure in specific regions of the monoblock instrument. The material properties are tailored locally to meet the mechanical and functional requirements of different portions of the instrument while maintaining overall manufacturing feasibility.
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 solution enables compact, cost-effective, and easily manufacturable endodontic instruments that can be held by a single instrument holder, reducing bulk and simplifying insertion and torque transmission.
Implementation Method 1
the shaft ( 10) and the handle (20) are formed integrally from a memory alloy material, in this example, a nickel-titanium-palladium (NiTiPd) alloy
Implementation Method 2
The shaft ( 10) and the handle (20) are formed integrally from a memory alloy material, in this example, a nickel-titanium-palladium (NiTiPd) alloy which has been heat treated to provide superelasticity
Data Source
Figure 1
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AI summary
The present invention relates to an endodontic instrument (1) having an active portion (11) which extends from the free end (110) thereof, and an assembly portion (12) which extends from the assembly end (120) thereof, wherein the assembly portion (12) has a locking segment, at which three flattened portions (121) are formed on the instrument (1), each of these three flattened portions (121) being respectively complementary, in each of the cross sections of the locking segment, to one of the sides of an equilateral triangle centred on the longitudinal axis (10) of the instrument, at least one of the flattened portions (121) being terminated, at the end thereof closest to said assembly end (120) of the instrument, by a shoulder (124) that is oriented substantially towards the free end (110) of the endodontic instrument.