Mandibular Advancement Device Friction Element Prevents Unscrewing
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Solution Overview
Problem
The existing Herbst apparatus for mandibular advancement faces issues with undesirable unscrewing between the threaded rod and maneuvering portion, which can compromise the effectiveness of orthodontic treatment, and the use of thread-lockers is unstable and ineffective at elevated temperatures.
Innovation Solution
Incorporating a friction element made of biocompatible materials like thermoplastic resin or photo-polymerizable acrylic composite, which is shaped to fit the thread of the pin and internal walls of the maneuvering portion, providing increased friction and preventing unscrewing, with a torque range of 1-10 Ncm to ensure secure coupling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a threaded rod is used to connect the maneuvering portion to the tube, then the distance between eyelets can be adjusted, but undesirable unscrewing may occur compromising treatment effectiveness
Solution Approach 1:
A friction element is introduced as an intermediary component between the threaded rod and the maneuvering portion. This friction element features an external surface with a thread profile that engages with the internal thread of the maneuvering portion, creating a mechanical intermediary connection that prevents unscrewing while maintaining adjustability.
Solution Approach 2:
The patent replaces the traditional thread-locker chemical method with a mechanical friction-based system. The friction element's thread profile creates mechanical interlocking with the maneuvering portion's internal thread, substituting chemical bonding with mechanical engagement to prevent unscrewing.
2Reliability
If thread-locker material is used to prevent unscrewing, then connection stability improves, but the material becomes unstable at temperatures of 30-40°C and may fragment or pulverize
Solution Approach 1:
The patent replaces the chemical thread-locker material with a mechanical friction element made of thermally stable materials. This friction element uses its thread profile to create mechanical engagement that is independent of temperature-dependent chemical bonding, eliminating the fragility issue at elevated temperatures.
Solution Approach 2:
The invention changes the fundamental parameter of the connection mechanism from chemical bonding (thread-locker) to mechanical engagement (friction element with thread profile). This parameter change results in a connection that maintains its properties across a wide temperature range without fragmenting or pulverizing.
3Strength
If thread-locker is used to increase friction, then initial connection strength improves, but braking effectiveness reduces during repeated maneuvers
Solution Approach 1:
The patent replaces the chemical friction mechanism (thread-locker) with a mechanical friction mechanism (friction element with thread profile). This mechanical system maintains consistent friction and braking effectiveness throughout repeated maneuvers because it relies on physical engagement rather than chemical bonding that degrades over time.
Solution Approach 2:
The friction element's thread profile creates a continuous mechanical engagement that maintains constant braking effectiveness during repeated maneuvers. Unlike thread-locker that degrades, the mechanical interlocking continues to provide stable friction and connection strength throughout the entire treatment duration.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution ensures reliable and secure coupling between the device's components, maintaining effectiveness over time, even at varying temperatures, and allows for the use of biocompatible materials, enhancing the device's reliability, accuracy, and cost-effectiveness.
Implementation Method 1
a friction element (3), arranged between the internal walls (24) of said maneuvering portion and the thread of the pin (2P) and having an external surface complementarily shaped with respect to the inner walls (24) of said maneuvering portion and a threaded internal cavity (32) which copies the thread of the pin (2P)
Data Source
AI summary
A device for mandibular advancement, including a tube and a telescopic rod associated with the tube, in which the tube and the telescopic rod can be associated to the teeth of the upper and lower arches, in which the telescopic rod includes a threaded pin which engages a female thread of a hollow element slidably positioned in said tube, and the hollow element includes a maneuvering portion external to the tube; the device includes a friction element, arranged between the inner walls of the maneuvering portion and the thread of the pin and having an outer surface which is complementary to the inner walls of said maneuvering portion and a threaded internal cavity which copies the thread of the pin.