Laser Pulse Timing for Cavity Cleaning

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Solution Overview

Problem

Existing methods for cleaning small cavities, such as root canals, are inefficient due to the limited generation of shock waves, which are essential for effective cleaning and disinfection, especially when using water as the irrigating liquid, as they do not effectively utilize the potential of shock waves in confined environments.

Innovation Solution

An apparatus that applies pulses of electromagnetic radiation to a cavity filled with a liquid, where the pulse repetition time is controlled based on the diameter or cross-sectional area of the cavity, ensuring the generation of shock waves even in small cavities, without the need for complex feedback systems or detailed geometry measurements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If laser pulses are applied to clean small cavities, then cleaning effect is improved, but shock wave generation is insufficient

Engineering Contradiction:
Improvecleaning effectVSAvoidshock wave generation
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent applies periodic laser pulsing with specifically controlled pulse repetition times to generate cavitation bubbles that collapse and produce shock waves. By using periodic action rather than continuous or random pulsing, the system optimizes bubble formation and collapse timing to maximize shock wave generation in small cavities.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent changes the pulse repetition time parameter based on cavity dimensions to optimize shock wave generation. By adjusting this temporal parameter according to the specific cavity size, the system ensures that bubble collapse occurs at the right moment to generate effective shock waves, resolving the contradiction between cleaning effect and shock wave production.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If pulse repetition time is controlled based on cavity dimensions, then shock wave generation is improved, but device complexity increases

Engineering Contradiction:
Improveshock wave generationVSAvoidcontrol system complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent implements preliminary action by pre-determining the optimal pulse repetition time based on cavity dimensions before treatment begins. The control unit is pre-programmed with the relationship between cavity size and optimal pulse timing, eliminating the need for complex real-time calculations or feedback systems during actual treatment.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system uses self-service by automatically selecting the appropriate pulse repetition time based on the measured cavity dimensions without requiring complex external control systems. The control unit internally processes the dimension data and adjusts pulsing parameters autonomously, reducing overall system complexity.

Inventive Principle:
Principle #25Self-service

3Reliability

If complex feedback systems are used to optimize shock waves, then cleaning efficacy is improved, but ease of operation deteriorates

Engineering Contradiction:
Improvecleaning efficacyVSAvoidsystem operation simplicity
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent extracts the essential control function to a simple dimension-to-time relationship, removing the need for complex feedback systems. By taking out only the necessary parameter (cavity dimension) and directly mapping it to the optimal pulse repetition time, the system maintains high cleaning efficacy while dramatically simplifying operation.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent uses copying by creating a pre-established relationship model between cavity dimensions and optimal pulse repetition times. This lookup table or predefined relationship allows the system to copy successful treatment parameters from the model without requiring complex real-time feedback, making the system easy to operate while maintaining effectiveness.

Inventive Principle:
Principle #26Copying

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

This approach allows for substantially improved cleaning of small cavities by optimizing the pulse repetition time based on the cavity's dimensions, enhancing the generation of shock waves and improving the cleaning efficacy, particularly in confined spaces like root canals.

Implementation Method 1

When energy is locally deposited within a liquid, for example with intense focused electromagnetic radiation (e.g., laser light)

Methodology Applied
Scientific EffectAbsorption of electromagnetic radiation: Absorption (EM radiation)

Implementation Method 2

Laser pulses produce plasma with subsequent bubble formation for ocular surgery by photo-disruption

Methodology Applied
Scientific EffectLaser heating: Laser

Implementation Method 3

locally induced boiling of the liquid leads to a creation of a cavitation bubble that rapidly expands due to the high pressure within the vapor. When the bubble reaches its maximum volume where the internal pressure is lower than in the surrounding liquid, the bubble starts to collapse

Methodology Applied
Scientific EffectCavitation: Cavitation

Implementation Method 4

Even more importantly, under appropriate conditions, an intense shock wave may be emitted during the bubble's collapse. These shock waves spread through the volume at supersonic speeds, and interact disruptively with the surrounding environment (e.g., cavity walls)

Methodology Applied
Scientific EffectShock wave: Shock Wave

Implementation Method 5

It is also known that a cavitation bubble collapsing near a boundary forms a liquid jet directed at the boundary

Methodology Applied
Scientific EffectCavitation jet: Cavitation

Data Source

PatentEP3791821A1Laser system and method for operating the laser system
Publication Date: 2021.03.17 FOTONA D O O
  • EP3791821A1 patent drawingFigure 1
  • EP3791821A1 patent drawingFigure 2a~2b
  • EP3791821A1 patent drawingFigure 3a~4b

AI summary

An apparatus and a method for cleaning a cavity filled with a liquid are disclosed. An apparatus (1) for applying pulses of electromagnetic radiation to a cavity (2) filled with a liquid (3) may comprise a source (4, 4') for generating a first pulse and a second pulse of electromagnetic radiation and a control unit (22) adapted to control a time between the first pulse and the second pulse as a function of a diameter D and/or a cross-sectional area of the cavity (2).