Dental Implant With Segmented Thread Geometry for Bone Anchoring
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Solution Overview
Problem
Dental implants often dislodge due to insufficient bonding area, especially in cancellous bone, which is weaker than cortical bone, leading to reduced anchoring forces and implant longevity.
Innovation Solution
A dental implant design featuring a coarsely threaded portion for cortical bone and a finely threaded portion for cancellous bone, with a primary thread of constant pitch and diameter, and secondary threads of the same pitch but smaller diameter, providing increased screw strength and bonding area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a single-threaded dental implant design is used, then the device complexity is reduced, but the anchoring strength in cancellous bone is insufficient
Solution Approach 1:
The screw thread is segmented into two distinct portions: a coarsely threaded portion with larger pitch for cancellous bone engagement, and a finely threaded portion with smaller pitch for cortical bone engagement. This segmentation allows each portion to optimize its thread characteristics for the specific bone type it contacts, thereby improving overall anchoring strength without requiring multiple separate components.
Solution Approach 2:
Different thread qualities are applied to different locations of the implant. The distal portion (in cancellous bone) has coarser threads with larger pitch and height, while the proximal portion (in cortical bone) has finer threads with smaller pitch. This local differentiation of thread quality ensures optimal mechanical interlocking in each bone type while maintaining a single integrated implant structure.
2Area of stationary object
If the thread pitch is increased to reduce threading complexity, then the ease of manufacture is improved, but the bonding area in cancellous bone is reduced
Solution Approach 1:
The thread structure is divided into segments with different pitch values. The coarsely threaded portion has a larger pitch optimized for cancellous bone bonding area, while the finely threaded portion has a smaller pitch optimized for cortical bone engagement. This segmentation allows each segment to have independently optimized parameters for its specific function and location.
Solution Approach 2:
The thread pitch parameter is changed along the length of the implant. The pitch increases from the proximal to distal end, with the coarsely threaded portion having a pitch of 0.5-1.5mm and the finely threaded portion having a pitch of 0.2-0.5mm. This parameter change optimizes the bonding area in cancellous bone while maintaining manufacturability through controlled variation.
3Strength
If the thread height is increased to improve anchoring in cancellous bone, then the anchoring strength is improved, but the device complexity increases
Solution Approach 1:
The thread geometry is segmented into two distinct regions: the coarsely threaded portion with larger thread height (0.3-1.0 times the outer diameter) for enhanced anchoring in cancellous bone, and the finely threaded portion with smaller thread height (0.1-0.3 times the outer diameter) for cortical bone engagement. This segmentation provides enhanced anchoring where needed while maintaining simpler geometry in other regions.
Solution Approach 2:
Different thread heights are applied locally to different portions of the implant. The distal portion features taller threads optimized for the softer cancellous bone, while the proximal portion features shorter threads suitable for the denser cortical bone. This local differentiation of thread height optimizes anchoring strength in each bone type without requiring the entire implant to have complex high-thread-geometry.
Data Source
AI summary
A dental implant with a coarsely threaded portion suitable for nesting within the cortical bone, and a finely threaded portion suitable for nesting within the cancellous bone. A primary thread with a constant pitch and a constant major diameter, runs along both the finely threaded portion and the coarsely threaded portion, and has a large thread height in the coarsely threaded portion, and a small thread height in the finely threaded portion. At least one secondary thread, having the constant pitch and the small thread height, runs along the finely threaded portion at an offset from the primary thread.