Orthodontic Screw Polygonal Through Opening
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Solution Overview
Problem
Existing orthodontic screws for extra-alveolar skeletal anchorage have unsuitable through holes for metal orthodontic wire sectors, making it difficult to secure these sectors for effective force transfer, and are made of surgical steel with poor cutting properties and an irregular surface morphology that can cause tissue irritation.
Innovation Solution
An orthodontic screw with a through opening in the engagement portion that extends orthogonally to the screw's longitudinal axis and has a polygonal cross section, specifically a rectangular cross section, to stably receive orthodontic wire sectors, and is made of titanium for improved biocompatibility and cutting properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If surgical steel is used for the orthodontic screw, then the material is readily available and inexpensive, but the cutting properties are poor and the surface morphology is irregular causing tissue irritation
Solution Approach 1:
The patent changes the material parameter from surgical steel to titanium, which fundamentally alters the cutting properties and surface morphology characteristics. Titanium provides superior cutting performance and creates a smoother surface that reduces tissue irritation, directly resolving the contradiction between material availability and harmful effects on tissue.
Solution Approach 2:
The patent employs titanium as a composite material solution that combines multiple desirable properties: excellent cutting characteristics, smooth surface morphology, and biocompatibility. This material selection resolves the contradiction by providing a substance that simultaneously achieves ease of manufacture through established titanium fabrication processes while eliminating tissue irritation through its inherent material properties.
2Ease of manufacture
If a circular through hole is provided in the screw head, then the manufacturing is simple, but the metal orthodontic wire sectors cannot be securely retained
Solution Approach 1:
The patent applies local quality by providing different cross-sectional shapes at different locations within the through opening. The opening has a circular entrance for easy wire insertion, then transitions to a polygonal cross-section (square, rectangular, or triangular) in the retention portion. This localized shape change enables both simple manufacturing and secure wire sector retention, resolving the contradiction between manufacturing simplicity and reliability.
Solution Approach 2:
The patent utilizes the transition from a circular entrance (curved geometry) to a polygonal retention section (angular geometry). The circular entrance facilitates easy insertion of the wire sector, while the angular polygonal section provides mechanical interlocking for secure retention. This geometric transition resolves the contradiction between simple manufacturing and reliable retention.
3Reliability
If the through opening has a complex polygonal cross section throughout, then the wire sectors are securely retained, but the manufacturing complexity increases
Solution Approach 1:
The patent segments the through opening into distinct functional zones: a simple circular entrance section for easy insertion, and a polygonal retention section for secure holding. This segmentation allows each portion to be optimized for its specific function while keeping the overall manufacturing complexity manageable, resolving the contradiction between reliability and device complexity.
Solution Approach 2:
The patent designs the through opening with a preliminary circular entrance section that guides and prepares the wire sector for insertion before it reaches the polygonal retention section. This preliminary action simplifies the insertion process and reduces the complexity of the retention mechanism, as the wire is pre-positioned correctly before engaging the complex polygonal geometry.
4Ease of manufacture
If the screw surface has irregular morphology, then the manufacturing is easier, but it causes tissue irritation and discomfort
Solution Approach 1:
The patent changes the surface morphology parameter from irregular to smooth through the selection of titanium material and appropriate surface finishing processes. This parameter change eliminates tissue irritation and discomfort while maintaining ease of manufacture through established titanium fabrication and surface treatment techniques.
Data Source
Figure 1
Figure 2~5
AI summary
The invention relates to an orthodontic anchor screw (100) for extra-alveolar skeletal anchorage comprising a threaded shank (10) configured to be screwed into a bone tissue and a head (20), which, in use, protrudes from the bone tissue and comprises an engagement portion (24) for orthodontic traction and/or thrust elements. A through opening (25) is formed in said engagement portion (24) for orthodontic traction and/or thrust elements, wherein said through opening (25) extends substantially along a direction (Y) orthogonal to a longitudinal axis (X) of the anchor screw (100) and comprises a section (25B) having a polygonal cross section, for stably receiving an orthodontic sector.