Variable Land Endodontic File Design for Taper Lock Reduction
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Solution Overview
Problem
Rotary endodontic files face issues with taper lock, reduced cutting efficiency, and deviation from the original canal path, especially in curved canals, due to uniform taper and flute geometry, leading to increased procedural steps and instrument breakage.
Innovation Solution
The development of rotary files with multiple heights of contour and varying land widths along the length, featuring a narrower waist in the middle, thinner lands at the tip and shank regions, and wider lands in the mid-region, reduces taper lock and maintains the original canal path while enhancing cutting efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If uniform taper and flute geometry are used in rotary endodontic files, then manufacturing is simplified, but taper lock occurs and cutting efficiency is reduced
Solution Approach 1:
The patent applies local quality by varying the land width along the length of the file. The land width is narrower at the tip and shank regions and wider in the mid-region, creating different cutting characteristics at different locations. This non-uniform geometry reduces taper lock and improves cutting efficiency while remaining manufacturable through conventional processes.
2Ease of manufacture
If uniform land width is used along the file length, then manufacturing is easier, but the file deviates from the original canal path in curved canals
Solution Approach 1:
The patent implements local quality by creating variable land widths along the file length, with thinner lands at the tip and shank and wider lands in the mid-region. This localized variation allows the file to maintain the original canal path in curved canals by reducing aggressiveness at critical regions while remaining manufacturable.
3Device complexity
If uniform land width is used, then device complexity is reduced, but instrument breakage increases due to cyclic fatigue
Solution Approach 1:
The patent applies local quality by varying land width along the file length, creating thinner lands at the tip and shank regions and wider lands in the mid-region. This non-uniform design reduces cyclic fatigue and instrument breakage by optimizing the distribution of mechanical stresses during rotation, while still being manufacturable through conventional processes.
4Manufacturing precision
If narrower land width is used at the tip, then cutting aggressiveness is reduced and canal path is maintained, but cutting efficiency decreases
Solution Approach 1:
The patent resolves this contradiction by applying local quality with variable land widths - narrower at the tip to maintain canal path accuracy and wider in the mid-region to provide sufficient cutting aggressiveness. The combination of different land widths at different locations achieves both canal path preservation and adequate cutting efficiency.
Solution Approach 2:
The patent applies segmentation by dividing the file into distinct regions (tip, mid-region, shank) with different land width characteristics. Each region is optimized for its specific function: the tip region maintains precision, the mid-region provides cutting power, and the shank region ensures durability, collectively achieving both accuracy and efficiency.
Data Source
AI summary
A tapered endodontic rotary file for shaping or cleaning a root canal in a tooth has one or more flutes spiraling along the length of the file. The diameters of the one or more flutes tapers in a non-uniform manner from a first diameter in a shank portion of the file to a smaller diameter in a tip portion of the file such that at least one flute region intermediate the shank portion and the tip portion has a diameter less than a straight line taper from the shank portion to the tip portion. The flutes can also be landed and the width of the lands can be varied along the length of the file. In particular, the width of the lands in the intermediate region are wider than the width in the tip or shank portion.