Endodontic Needle Cavitation Irrigation for Root Canal Debridement

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Solution Overview

Problem

Existing root canal treatment methods are laborious, time-consuming, and have a high failure rate due to incomplete bacteria removal and tooth structure weakening, primarily because of limitations in mechanical filing and irrigation techniques that cannot access small canals, leading to reinfection and structural damage.

Innovation Solution

An endodontic apparatus with a needle having a length of at least 3mm and external diameter of no more than 520 µm, delivering irrigant at a pressure exceeding a cavitation threshold to generate a cloud of inertial cavitation within the root canal, facilitating effective debridement and disinfection without mechanical filing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If mechanical files are used to enlarge canals for better irrigation access, then irrigation effectiveness is improved, but tooth structure is weakened and more susceptible to cracks

Engineering Contradiction:
Improveirrigation effectivenessVSAvoidtooth structure strength
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent replaces mechanical filing with a fluid-based system. A jet of irrigant fluid is directed through a nozzle into the root canal to create hydrodynamic cavitation, eliminating the need for mechanical enlargement of the canal while still achieving effective irrigation and debridement through cavitation bubbles that detach and travel through the canal.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent uses hydraulic principles by delivering a high-velocity jet of irrigant fluid through a nozzle. The fluid jet creates cavitation through pressure changes and hydrodynamic effects, utilizing fluid mechanics to achieve cleaning and disinfection without mechanical contact with the tooth structure.

Inventive Principle:
Principle #29Pneumatics and hydraulics

2Reliability

If mechanical files are used to enlarge canals, then access to small canals is improved, but treatment time and labor are substantially increased

Engineering Contradiction:
Improveaccess to small canalsVSAvoidtreatment time
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent replaces time-consuming mechanical filing with an immediate fluid-based cavitation system. The nozzle delivers irrigant fluid that rapidly generates cavitation bubbles throughout the canal system, providing access to small canals without the need for progressive mechanical enlargement, thereby dramatically reducing treatment time.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Ease of operation

If conventional syringe irrigation is used, then the procedure is simple, but it cannot access all small and complex canal structures leaving bacteria behind

Engineering Contradiction:
Improveirrigation simplicityVSAvoidbacteria removal completeness
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent uses hydrodynamic cavitation created by the fluid jet through the nozzle. The rapid formation and collapse of cavitation bubbles creates intense local mixing and mechanical action that propels irrigant into complex canal structures, achieving complete bacteria removal while maintaining operational simplicity.

Inventive Principle:
Principle #18Mechanical vibration

4Reliability

If negative pressure suction is used to prevent vapour lock, then irrigation effectiveness is improved, but substantial instrumentation is required to enlarge canals to fit two irrigation needles

Engineering Contradiction:
Improvevapour lock preventionVSAvoidinstrumentation complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts the function of vapour lock prevention from complex multi-needle systems with negative pressure suction. Instead, a single nozzle delivers irrigant fluid that creates cavitation bubbles, which naturally prevent vapour lock formation through the intense mixing and gas release, eliminating the need for substantial canal enlargement and complex instrumentation.

Inventive Principle:
Principle #2Taking out (Extraction)

5Reliability

If sonic or ultrasonic vibrating tips are used, then debridement and disinfection are improved in larger canals, but they require significant prior instrumentation and filing

Engineering Contradiction:
Improvedebridement effectivenessVSAvoidprior instrumentation requirement
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces sonic/ultrasonic vibration with hydrodynamic cavitation. The fluid jet through the nozzle generates cavitation bubbles that provide debridement and disinfection effects without requiring mechanical vibration, and crucially, without requiring prior canal instrumentation or filing to accommodate vibrating tips.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 apparatus effectively cleans and disinfects root canals, reducing treatment time and minimizing tooth damage by generating inertial cavitation, thereby improving debridement and disinfection efficiency.

Implementation Method 1

the pump delivers irrigant at a delivery pressure in excess of a threshold cavitation pressure that gives an exit velocity of the irrigant at the needle tip of at least 20 m/s such that the flow of irrigant through the needle generates a backflow in the root canal to facilitate forming of a cloud of inertial cavitation within the irrigant fluid in the root canal forward of the needle tip

Methodology Applied
Scientific EffectCavitation: Cavitation

Data Source

PatentEP4304517B1Endodontic apparatus
Publication Date: 2026.03.04 ODNE AG
  • EP4304517B1 patent drawingFigure 1~2
  • EP4304517B1 patent drawingFigure 3(A)~3(D)

AI summary

A dental apparatus (1) and method, for example an endodontic apparatus and method, is disclosed. The apparatus comprises: a supply of fluid (12); a pump (14) for delivering fluid from the supply (12) under pressure and a handpiece 20 in fluid communication with the pump (14). The handpiece (20) comprises a needle (30), extending from a rearward end proximal to the handpiece to a forward tip distal from the handpiece, a lumen of the needle extending to an opening at the tip to deliver fluid received from the pump to a tooth. The dimensions of the needle and the delivery pressure of the fluid are selected such that the flow of fluid through the needle causes a cloud of inertial cavitation to be formed forward of the needle tip.