Dental Handpiece Load Control for Root Canal Cutting

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Solution Overview

Problem

Existing dental treating apparatuses face challenges in efficiently cutting tooth root canals while preventing cutting tool breakage due to excessive load, as they often fail to sufficiently reduce the load applied during reverse rotation, leading to inefficient cutting and potential tool breakage.

Innovation Solution

A dental treating apparatus with a hand piece, driving unit, load detecting unit, and control unit that compares the applied load to a reverse rotation reference load, controlling the driving unit to ensure the load is sufficiently reduced during reverse rotation, thereby preventing excessive load on the cutting tool and optimizing cutting efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If the cutting tool is rotated counterclockwise to reduce load, then the applied load is reduced, but the cutting efficiency decreases because the cutting tool does not contribute to cutting the tooth

Engineering Contradiction:
Improveapplied loadVSAvoidcutting efficiency
Core Design Contradiction:
ForceVSProductivity

Solution Approach 1:

The cutting tool alternates between clockwise rotation (cutting phase) and counterclockwise rotation (load reduction phase) in periodic cycles. This periodic action allows the tool to cut efficiently during clockwise rotation while reducing load during counterclockwise rotation, resolving the contradiction between maintaining high cutting efficiency and reducing applied load

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The counterclockwise rotation is performed as a preliminary action before the next clockwise cutting phase to preemptively reduce accumulated load and prevent tool breakage. This anti-action prepares the system for the next cutting cycle by ensuring load is reduced in advance, allowing sustained high-efficiency cutting

Inventive Principle:
Principle #9Preliminary anti-action

2Productivity

If the cutting tool rotates clockwise to cut the tooth, then cutting efficiency is improved, but the load applied to the cutting tool increases causing potential breakage

Engineering Contradiction:
Improvecutting efficiencyVSAvoidapplied load
Core Design Contradiction:
ProductivityVSForce

Solution Approach 1:

The system uses periodic alternation between clockwise cutting rotation and counterclockwise load-reduction rotation. During clockwise rotation, cutting efficiency is maximized; during counterclockwise rotation, load is reduced. This periodic cycle prevents continuous high load accumulation while maintaining overall cutting progress

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The twist driving mechanism ensures continuous useful action by maintaining a net forward cutting progress over each complete cycle. Although counterclockwise rotation temporarily reduces load, the overall process continues to advance the cutting tool through the root canal, ensuring continuous treatment progress without interruption

Inventive Principle:
Principle #20Continuity of useful action

3Productivity

If reverse rotation is performed to discharge cut pieces, then the root canal is cleared, but the load is not sufficiently reduced leading to tool breakage

Engineering Contradiction:
Improveroot canal clearingVSAvoidtool durability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The system changes rotational parameters (direction, speed, duration) dynamically based on treatment stage. During reverse rotation for debris discharge, the rotation speed and duration are optimized to effectively clear the canal while controlling load reduction. The parameters are adjusted to ensure load falls within a safe range before resuming forward rotation, preventing tool breakage

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The control unit monitors treatment progress and adjusts reverse rotation parameters based on feedback from the treatment state. When cut pieces need discharge, the system performs controlled reverse rotation with parameters adjusted to achieve adequate load reduction while clearing the canal, then resumes forward rotation only when load is sufficiently reduced

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP2851034B1Dental treating apparatus
Publication Date: 2017.11.08 J MORITA MANUFACTURING CORP
  • EP2851034B1 patent drawingFigure 1
  • EP2851034B1 patent drawingFigure 2
  • EP2851034B1 patent drawingFigure 3~4

AI summary

A dental treating apparatus according to the present invention includes: a hand piece (1); a head unit (2); a driving unit (13); a resistor (13d) for load detection; a load comparing unit (110); and a control unit (11). The hand piece (1) drivably holds a cutting tool (5) on the head unit (2). The driving unit (13) drives the cutting tool (5) in a normal rotation direction or in a reverse rotation direction. The resistor (13d) for load detection detects a load applied to the cutting tool (5). The load comparing unit (110) compares the detected load and a reference load each time driving for rotating the cutting tool (5) in the reverse rotation direction by a predetermined rotation angle is performed. The control unit (11) controls the driving unit (13) based on a result of comparison by the load comparing unit (110).