Self-Tapping Implant Thread Design for Low-Torque Bone Debris Clearance
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Solution Overview
Problem
Existing self-tapping implants face challenges with high insertion torque requirements and micromotion, leading to bone absorption and potential implant failure, as they struggle to effectively clear bone debris during the threading process.
Innovation Solution
A self-tapping implant design featuring a helical thread with a secondary helix running in the opposite direction, which reduces the need for high torque by distributing debris evenly along the implant body, thereby minimizing micromotion and stabilizing the implant upon insertion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If traditional self-tapping implant designs are used, then initial stabilization is provided through thread engagement, but high insertion torque is required and bone chips accumulate creating resistance
Solution Approach 1:
The implant thread is segmented into cutting surfaces and engagement surfaces. The cutting surfaces at the leading edge cut bone to create threads, while the engagement surfaces follow behind to engage the cut threads. This segmentation allows the implant to cut its own threads with reduced torque while maintaining initial stability through proper thread engagement.
Solution Approach 2:
The cutting surfaces perform preliminary action by cutting the bone threads before the engagement surfaces arrive. This preliminary cutting action creates the thread form in advance, allowing the engagement surfaces to simply engage rather than force their way in, significantly reducing insertion torque while ensuring proper thread formation for initial stability.
2Reliability
If cutting threads are used to engage bone, then initial stabilization is achieved, but large amounts of bone chips are generated that increase insertion torque and may cause breakage
Solution Approach 1:
The harmful bone chips are extracted from the insertion zone by the flutes. The flutes are positioned to receive and transport chips away from the cutting and engagement surfaces as the implant is inserted. This extraction of chips prevents accumulation that would otherwise increase torque and cause thread breakage, while the cutting surfaces continue to form stable threads.
Solution Approach 2:
The flutes act as an intermediary between the cutting surfaces and the implant body. They provide a pathway for bone chips to be removed from the cutting zone, mediating the harmful effect of chip accumulation. The flutes transport chips away without interfering with the thread cutting and engagement process, maintaining both low torque and high initial stability.
3Loss of substance
If parallel flutes are used to clear bone chips, then debris removal is aided, but the collection of chips increases torque required to seat the implant
Solution Approach 1:
The flutes are positioned in a different spatial arrangement - adjacent to and parallel with the cutting surfaces rather than collecting chips in a central location. This dimensional change in chip evacuation pathway allows chips to be removed laterally along the implant length rather than being collected in one place, reducing torque while maintaining effective clearance.
Data Source
AI summary
The invention relates to methods of stabilizing bone implants, including inserting a self-tapping implant having at least two helical grooves running in opposite directions around the implant.