Laser Dental Cooling Fluid Flow Control

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Solution Overview

Problem

Current laser-based dental treatment systems using mid to far-infrared wavelengths for cutting tooth enamel are inefficient due to excessive coolant interference with the laser beam, leading to slow material removal rates and enamel melting, which is exacerbated by the absorption characteristics of hydroxyapatite and non-apatite CaP phases.

Innovation Solution

A system that regulates the flow of a coolant fluid to minimize enamel melting while maximizing laser energy absorption, using a combination of liquid and gas delivery with adjustable pressure and flow control to prevent coolant interference with the laser beam, ensuring sufficient cooling without attenuating the laser power, and employing computer-controlled laser beam delivery and nozzle orientation to direct the coolant effectively.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If coolant fluid is provided to cool the treatment area during laser cutting, then thermal damage to enamel is prevented, but the coolant absorbs laser radiation and reduces material removal rate

Engineering Contradiction:
Improvethermal damage to enamelVSAvoidmaterial removal rate
Core Design Contradiction:
Object-affected harmful factorsVSProductivity

Solution Approach 1:

The patent changes the physical parameters of the coolant delivery system by adjusting flow rate, pressure, and delivery timing to optimize the balance between cooling effectiveness and laser beam transmission. By controlling these parameters, the system provides adequate cooling while minimizing coolant interference with the laser beam, thus maintaining high material removal rates.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent implements periodic delivery of coolant fluid in synchronization with laser pulse delivery. The coolant is delivered during intervals between laser pulses or in coordinated cycles, allowing the laser beam to pass through with minimal obstruction while still providing continuous cooling to prevent enamel melting and thermal damage.

Inventive Principle:
Principle #19Periodic action

2Temperature

If coolant flow rate is increased to prevent enamel melting, then thermal protection is improved, but laser energy absorption by coolant increases and cutting efficiency decreases

Engineering Contradiction:
Improveenamel temperature controlVSAvoidlaser energy absorption
Core Design Contradiction:
TemperatureVSUse of energy by moving object

Solution Approach 1:

The system dynamically adjusts coolant flow rate, pressure, and delivery timing parameters to achieve optimal temperature control with minimal energy loss. By fine-tuning these parameters, the patent ensures sufficient cooling to prevent enamel melting while keeping coolant absorption of laser energy at acceptable levels, thereby maintaining cutting efficiency.

Inventive Principle:
Principle #35Parameter changes

3Ease of operation

If coolant is delivered between laser pulses, then cooling is provided during treatment, but the treated surface experiences thermal cycles causing melting during laser pulses

Engineering Contradiction:
Improvecooling during treatmentVSAvoidsurface temperature stability
Core Design Contradiction:
Ease of operationVSTemperature

Solution Approach 1:

The patent implements a periodic coolant delivery system synchronized with the laser pulse sequence. Coolant is delivered during intervals between laser pulses and withheld during pulse delivery, creating a coordinated rhythm that provides cooling when needed while allowing laser energy to effectively ablate material without causing thermal cycles that lead to melting.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The system delivers coolant in advance during intervals between laser pulses, preparing the tissue for the next laser pulse by removing heat accumulated during previous pulses. This preliminary cooling action prevents excessive temperature buildup that would cause melting during subsequent laser pulses.

Inventive Principle:
Principle #10Preliminary action

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 enhances the efficiency of dental tissue removal by maintaining peak absorption of laser energy, minimizing enamel melting, and preventing coolant pooling, thereby achieving faster and more precise cutting with reduced thermal damage.

Implementation Method 1

Some systems that deliver coolant between laser pulses do not provide forced convective cooling from the surface of the dental region being treated at or nearly at the time the surface is being heated.

Methodology Applied
Scientific EffectForced convection: Forced Convection

Implementation Method 2

Lasers have also been found to be useful in the removal of dental material with less amount of local anesthetic than that required when the procedure is performed with a drill.

Methodology Applied
Scientific EffectLaser ablation: Laser Ablation

Implementation Method 3

Laser wavelengths in the range of 5 to 15 μm are strongly absorbed by the hydroxyapatite that makes up to about 96% of tooth enamel by weight.

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

Implementation Method 4

the applied laser energy is absorbed in water in tooth enamel (about 4% by volume), causing the water to vaporize, and the resulting steam causing to facture the hard tissue/enamel

Methodology Applied
Scientific EffectWater absorption: Absorption (EM radiation)

Data Source

PatentEP2849671B1Apparatus for laser based dental treatment with controlled fluid cooling
Publication Date: 2021.04.07 CONVERGENT DENTAL INC
  • EP2849671B1 patent drawingFigure 1~2
  • EP2849671B1 patent drawingFigure 3
  • EP2849671B1 patent drawingFigure 4A

AI summary

A system for dental tissue treatment includes a system for directing a laser beam to an area of dental tissue to be treated, and a fluid-delivery system for directing and controlling a flow of a fluid. The fluid is directed to at least a portion of the area to be treated and the fluid flow is controlled to substantially prevent both a change in laser energy absorption by the dental tissue and attenuation of treatment efficiency due to fluid interference with the laser beam. The fluid present in at least a portion of the area to be treated may prevent or reduce the likelihood of melting of enamel in that area.