Endodontic File Elastomeric Friction Grip Torque Control
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Solution Overview
Problem
Current endodontic files face issues such as fracture during use due to excessive force, inadequate cleaning in oval or narrow canals, and risk of perforation, especially in curved canals, due to their moderate elasticity and lack of torque control, limiting their use and increasing treatment costs.
Innovation Solution
An endodontic file with a central longitudinal cord, a helically wound wire, and an elastomeric grip that supports the file only by friction within a dental handpiece, limiting torque and preventing breakage by slipping if excessive shear force is applied, allowing for safe high-speed operation and precise canal preparation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If rotary nickel-titanium files are used for mechanical shaping, then shaping efficiency is improved, but fracture risk increases
Solution Approach 1:
The elastomeric grip acts as a cushioning element between the handpiece and the file. It is designed with a friction coefficient that allows torque transmission during normal operation but slips when excessive torque is applied, preventing file fracture. This prior cushioning mechanism protects against the harmful effect of torque overload before it can cause damage.
2Reliability
If dedicated handpiece systems with torque control are used, then file fracture is prevented, but device complexity and cost increase
Solution Approach 1:
The torque control function is extracted from the complex dedicated handpiece system and transferred to the simple elastomeric grip component. This allows standard handpieces to be used without modification while still providing fracture protection through the friction-based slip mechanism in the grip.
Solution Approach 2:
The elastomeric grip is a simple, inexpensive component that can be easily replaced if worn. It provides an affordable alternative to expensive dedicated handpiece systems with electronic torque control circuits.
3Productivity
If high rotation speed is used for efficient cleaning, then productivity is improved, but torque control ability deteriorates
Solution Approach 1:
The elastomeric grip provides self-regulating torque control during high-speed rotation. As the file encounters resistance in the canal, the grip automatically slips when torque exceeds the friction threshold, providing passive torque control without requiring electronic sensors or active control mechanisms.
4Ease of manufacture
If round cross-section files are used, then manufacturing is simplified, but cleaning effectiveness in oval canals deteriorates
Solution Approach 1:
The file is designed with flexibility allowing it to dynamically adapt its shape to the canal geometry. The combination of the central cord and helically wound wire allows the file to bend and conform to oval or irregular canal cross-sections while maintaining its simple round manufacturing form.
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 safe and efficient canal preparation with reduced risk of file breakage and dentine layer damage, facilitating complete canal cleaning and shaping without perforation, even in complex canal geometries, while allowing non-experts to use high-speed rotary files with confidence.
Implementation Method 1
an elastomeric grip partially covering the helically wound wire near a first end thereof and having an outer diameter that is slightly wider than an internal diameter of a barrel of a dental instrument whereby on insertion into the barrel it is supported therein only by friction
Implementation Method 2
The thin, flexible portion of the device is centrifugally thrown against the canal wall following the natural curvature and complex cross-section of the root canal in exact manner
Data Source
AI summary
An endodontic file (10) has at least a central longitudinal cord (12), a helically wound wire (14) at least partially surrounding the cord and an elastomeric grip (16) partially covering the helically wound wire near a first end thereof and having an outer diameter that is slightly wider than an internal diameter of a barrel of a dental instrument whereby on insertion into the barrel it is supported therein only by friction.