Segmented Root Canal Reamer Apical Preparation
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Solution Overview
Problem
Current root canal reamers face challenges in achieving high taper apical preparation without modifying the existing canal configuration, are prone to self-screwing, and lack flexibility, making apical widening complex and prone to instrument breakage.
Innovation Solution
A root canal reamer with two cutting edges, featuring a linear and symmetrical configuration at the apical portion with a high angle, transitioning to helical cutting edges with increasing pitch, allowing for a high taper in the tip section while maintaining modest taper for flexibility, enabling precise and uniform apical preparation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If root canal reamers have high taper at the tip to widen apical portion, then apical preparation efficiency is improved, but the instrument becomes prone to breakage and self-screwing
Solution Approach 1:
The root canal reamer is divided into two distinct sections: an apical portion with high taper (10-25%) for efficient apical preparation, and a proximal portion with low taper (1-3%) for flexibility and resistance to breakage. This segmentation allows each section to have optimized properties for its specific function, resolving the contradiction between apical preparation efficiency and instrument reliability.
Solution Approach 2:
Different parts of the reamer have different geometric properties: the tip portion has a conical shape with high taper angle and two linear cutting edges for aggressive apical widening, while the proximal portion has a cylindrical shape with low taper and helical flutes for flexibility and debris removal. This local differentiation of quality allows the instrument to simultaneously achieve high apical preparation efficiency and resistance to breakage.
2Ease of operation
If root canal reamers have helical cutting edges to remove debris, then debris removal is improved, but the instrument tends to self-screw in the canal
Solution Approach 1:
The helical flutes are applied only to the proximal portion of the reamer, not the apical portion. The apical portion has two linear cutting edges that cut debris and allow it to be removed without creating self-screwing action. The proximal portion's helical flutes then remove the debris generated by the apical portion without causing self-screwing, as they are positioned where the instrument has already entered the canal.
3Adaptability or versatility
If root canal reamers have low taper to follow root canal curvature, then flexibility is improved, but apical portion widening capability is reduced
Solution Approach 1:
The reamer shaft is segmented into two portions with different tapers: the proximal portion has low taper (1-3%) that provides flexibility to follow the curvature of the root canal, while the apical portion has high taper (10-25%) that provides aggressive cutting action for rapid apical widening. This segmentation resolves the contradiction between flexibility and apical widening capability.
Solution Approach 2:
Different sections of the reamer have different geometric properties optimized for different functions: the proximal portion has low taper and helical flutes for flexibility and debris removal, while the apical portion has high taper and linear cutting edges for aggressive apical preparation. This local quality differentiation allows simultaneous achievement of flexibility and apical widening capability.
4Productivity
If multiple manual reamers with increasing diameter are used to widen apical portion, then apical preparation is achieved, but the operation becomes complex and time-consuming
Solution Approach 1:
The invention merges the functions of multiple sequential reamers into a single instrument. The unique combination of high taper apical portion with low taper proximal portion allows one reamer to perform the apical widening function that previously required multiple instruments with progressively increasing diameters, thereby reducing device complexity and procedural time while maintaining complete apical preparation.
Data Source
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Figure 2
AI summary
A new root canal reamer, with two cutting edges, particularly flexible, having in the apical portion strongly converging linear cutting edges lying on the same plane as the axis of the root canal reamer and with taper greater than the rest of the instrument. Said root canal reamer has a highly tapered apical section, while the remaining working part has a modest taper to ensure flexibility of the instrument.