Multi-directional Handpiece Synchronized Rotation and Oscillation
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Solution Overview
Problem
Current contra angle handpieces either rotate the file or oscillate it up and down without rotation, leading to over torque, cyclical fatigue, and reduced cutting efficiency during root canal procedures, as they fail to balance rotational and axial movements effectively.
Innovation Solution
A multi-directional handpiece that simultaneously rotates the file clockwise, counterclockwise, or reciprocates while oscillating it vertically, allowing for controlled axial movement to reduce torque and cyclical fatigue exposure, achieved through a design with a fixed pin, motor drive, follower member with radial grooves, and longitudinal ribs and grooves for synchronized rotation and oscillation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the file is rotated to improve cutting efficiency, then cleaning and shaping efficiency increases, but the file becomes susceptible to over torque and cyclical fatigue
Solution Approach 1:
The handpiece implements periodic reciprocating motion where the file oscillates between clockwise and counterclockwise rotation around a central axis. This periodic action allows the file to engage with the root canal effectively while periodically reversing direction to prevent continuous rotational stress accumulation, thereby reducing over torque and cyclical fatigue while maintaining cutting efficiency
2Reliability
If the file oscillates up and down without rotation to prevent over torque, then file strength is improved, but cutting efficiency is significantly reduced
Solution Approach 1:
The handpiece merges rotational and oscillating motions into a single integrated movement. The file simultaneously rotates around its own axis while oscillating up and down along the root canal axis, combining the cutting efficiency of rotation with the torque reduction benefits of oscillation. This combined motion allows the file to maintain engagement with the canal while periodically changing direction to prevent excessive torque accumulation
3Reliability
If the file rotates in reciprocation motions to balance torque, then file strength is improved, but the motion becomes complex requiring multiple components
Solution Approach 1:
The handpiece employs a universal motion control mechanism that simultaneously generates both rotational and oscillating movements through a single integrated drive system. The reciprocating motor assembly produces complex motion patterns that combine clockwise and counterclockwise rotation with vertical oscillation, allowing one mechanism to perform multiple functions: maintaining file engagement, reducing torque, and preventing fatigue without requiring separate independent drive systems
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
Enhances cleaning and shaping efficiency of root canals by balancing rotational and axial movements, reducing the risk of file separation and maintaining cutting efficiency while minimizing torque and cyclical fatigue.
Implementation Method 1
a motor gearing at a proximal end of the motor drive; and a file gearing in engagement with the motor gearing for transferring the rotational and axial movement of the motor drive about the body axis to the file drive about the file head axis
Implementation Method 2
a follower member including a radial groove having opposing spaced apart walls, the walls including a plurality of sections (e.g., curves) having a first section being displaced axially relative to a second section along the head axis to define an offset path that is dimensioned for receiving the fixed pin
Data Source
Figure 1~2
Figure 3
Figure 4~6
AI summary
A multi-directional handpiece that includes a motor drive extending along and configured for rotation about a body axis, the motor drive having: a motor gearing at a proximal end of the motor drive; and a file gearing in engagement with the motor gearing for transferring the rotational and axial movement to a workpiece; and a housing for the workpiece; and wherein through rotation of the motor drive, the workpiece moves in an axial oscillating motion while being rotated.