Differential Archwire Segmentation for Orthodontic Torque Control
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Solution Overview
Problem
Current orthodontic archwire designs face challenges in controlling bucco-lingual inclination of incisors during retraction while minimizing friction on posterior teeth, leading to issues like incisor rotation and excessive friction, which are not adequately addressed by existing techniques such as sliding mechanics, bidimensional techniques, or designs with round and super-elastic materials.
Innovation Solution
The differential archwire features an anterior segment with a larger cross-sectional area for controlling incisor inclination and two posterior segments with smaller cross-sectional areas for low friction, allowing for precise control and smooth sliding, made from materials like stainless steel with rectangular cross-sections that enhance rigidity and flexibility, respectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If an archwire with big cross-sectional size is used, then good control of bucco-lingual inclination of incisors is achieved, but too much friction is generated on posterior teeth brackets
Solution Approach 1:
The archwire is divided into two segments with different cross-sectional dimensions: an anterior segment (0.46x0.56mm) for incisor control and posterior segments (0.46x0.46mm or smaller) for reduced friction. This segmentation allows each portion to perform its specific function optimally without compromising the other.
Solution Approach 2:
Different portions of the archwire have different cross-sectional characteristics tailored to their specific functions. The anterior segment has larger dimensions (0.46x0.56mm) to provide torque control, while posterior segments have smaller dimensions (0.46x0.46mm or 0.43x0.46mm) to minimize friction, creating local quality variations along the wire.
2Object-affected harmful factors
If an archwire with small cross-sectional size is used, then low friction and good sliding along posterior teeth brackets is achieved, but no control to bucco-lingual inclination of incisors is provided
Solution Approach 1:
The archwire is divided into two segments with different cross-sectional dimensions: an anterior segment (0.46x0.56mm) for incisor control and posterior segments (0.46x0.46mm or smaller) for reduced friction. This segmentation allows each portion to perform its specific function optimally without compromising the other.
Solution Approach 2:
Different portions of the archwire have different cross-sectional characteristics tailored to their specific functions. The anterior segment has larger dimensions (0.46x0.56mm) to provide torque control, while posterior segments have smaller dimensions (0.46x0.46mm or 0.43x0.46mm) to minimize friction, creating local quality variations along the wire.
3Object-affected harmful factors
If round cross-section posterior segments are used, then friction reduction is achieved, but enough rigidity along horizontal plane is not generated causing tooth tipping
Solution Approach 1:
The posterior segments use rectangular cross-section (0.46x0.46mm or 0.43x0.46mm) instead of round, providing sufficient rigidity along the horizontal plane to prevent tooth tipping while maintaining lower friction compared to a uniform thick rectangular wire. The rectangular shape optimizes the balance between rigidity and friction reduction.
Data Source
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AI summary
The content of the present invention is a "differential archwire", to be utilized as a component of the fixed orthodontic appliance. The "differential archwire" is utilized to retract the incisors, and it can be used in association with the brackets today available on the market. The "differential archwire" is characterized by an anterior segment (11) with big cross-section area, and by two posterior segments (12,13) with smaller cross-section area. The anterior segment (11) completely fills the slot of the brackets of the incisors, and gives good control of the torque of the incisors during their retraction. The posterior segments (12-13) have smaller cross-section area in order to reduce the friction and to allow good sliding of the archwire along the brackets of the posterior teeth, canine, premolars, molars. The "differential archwire" is constituted preferably, but not necessarily, by stainless steel. The shape of the cross-section of the differential archwire is preferably, but not necessarily, rectangular with the long side of the rectangle placed along the horizontal plane. This design of the cross-section shape gives higher rigidity to the archwire along the horizontal plane, in order to help to keep a correct transversal diameter of the dental arches during the closure of the spaces present in the dental arches.