Endodontic File Spiral Cord Structure for Canal Adaptation
Solution Overview
Problem
Existing endodontic files face issues such as unintended penetration of the root canal wall due to rigidity and small diameter, and abrasive particles separating from the binder during use, leading to inefficiencies and potential damage.
Innovation Solution
An endodontic file design featuring a central cord and spiral cord integrated structure with varying pitch for flexibility, a reinforced portion for reduced fracture risk, and an abrasive outer surface formed by metal grains for effective canal preparation, along with a handle that acts as a safety clutch to prevent file breakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the central cord is made rigid to maintain structural integrity, then the file can effectively remove material, but the file may unintentionally penetrate the side wall of the root canal
Solution Approach 1:
The patent employs a flexible outer coil structure that envelops the central cord. This flexible shell allows the file to adapt to the root canal's natural curvature and conform to the canal walls without penetrating them, while the central cord maintains structural integrity for effective material removal.
2Productivity
If abrasive particles are embedded in a binder coating on the file surface, then material removal is effective, but the abrasive particles can separate from the binder and become dislodged in the tooth canal
Solution Approach 1:
The patent utilizes a porous ceramic matrix as the abrasive material itself. This porous structure allows the abrasive to be self-retaining within the file structure, eliminating the need for binder coatings that could fail and release particles into the canal while maintaining effective material removal capabilities.
3Adaptability or versatility
If the central cord diameter is reduced to improve flexibility, then the file can better adapt to canal shapes, but the file becomes subject to penetration through the wall of the dental cavity due to rigidity
Solution Approach 1:
The patent creates a composite structure combining a flexible outer coil with a central cord. This composite design allows the outer coil to provide flexibility and adaptability to canal shapes, while the central cord maintains sufficient diameter and rigidity to prevent penetration through the cavity wall, resolving the contradiction between flexibility and structural stability.
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 design allows for safe and effective root canal preparation with reduced risk of fracture, improved flexibility to adapt to canal shapes, and enhanced material removal capabilities while preventing particle separation, enabling efficient and precise canal shaping.
Implementation Method 1
an abrasive outer surface configured for removing material from a wall of the root canal upon rotation of the endodontic file within the root canal
Implementation Method 2
the handle is adapted to be gripped in a handpiece by friction alone. This act as a safety clutch that helps to prevent fracture of the endodontic file should it snag inside the root canal
Data Source
Figure 1~2b
Figure 3a~3b
Figure 4a~5b
AI summary
An endodontic file (10) has a handle (11) and a spiral cord (15) of helically wound metallic wire wound in a predetermined direction around a central metallic cord (13) formed between opposite ends of the central cord so as to form an integrated structure (18) of generally conical cross-section including a narrow tip end (17) and an opposite wider upper end (16) supported at the upper end by the handle. A flexible conical reinforcement (26, 31) supported by the handle covers an outermost layer of an upper portion of the spiral cord remote from the tip end, its lower end being of sufficiently low diameter to enter the root canal and dimensioned at its upper end to limit bending of the upper portion. An outer surface (20) of the spiral cord is configured for removing material from inside the root canal when the endodontic file is rotated in the predetermined direction.