Endodontic Cement Ultrasonic Reprocessing via Calcium Phosphate
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Solution Overview
Problem
Existing endodontic cements used in root canal treatments are difficult to reprocess, often requiring potentially toxic solvents to reduce hardness, making revision operations challenging and potentially hazardous.
Innovation Solution
A dental product comprising a powder composition of calcium phosphate, a binder, and a liquid medium, which sets naturally in humidity to form a biocompatible cement with controlled viscosity and compressive strength, allowing for easy recovery with ultrasound, including a radiopaque contrast agent and a setting accelerator.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If existing endodontic cements are used to provide strong sealing, then the root canal filling is stable and durable, but the cement becomes too hard to reprocess without toxic solvents
Solution Approach 1:
The patent changes the chemical composition parameters of the cement by using a specific ratio of calcium phosphate powders (40-55% mass content) combined with organic acids (0.5-5% mass content) and water-soluble polymers. This parameter optimization allows the cement to achieve adequate compressive strength (3-15 MPa) while maintaining lower hardness that facilitates ultrasonic reprocessing without requiring toxic solvents.
Solution Approach 2:
The patent creates a composite cement material combining calcium phosphate powders (providing strength and biocompatibility), organic acids (controlling setting and hardness), and water-soluble polymers (providing viscosity control and reprocessing capability). This composite approach achieves the balance between sufficient sealing strength and ease of revision by leveraging the complementary properties of each component.
2Ease of repair
If the cement is made softer for easy reworking, then ultrasonic removal becomes easier, but the sealing effectiveness and cohesion are reduced
Solution Approach 1:
The patent optimizes the mass content of calcium phosphate powders to 40-55%, which provides sufficient compressive strength (3-15 MPa) for effective sealing while maintaining lower hardness for easy ultrasonic reprocessing. This parameter range achieves the balance between sealing reliability and reworking ease.
Solution Approach 2:
The composite formulation combines calcium phosphate powders (for strength and sealing), organic acids (for controlled setting and moderate hardness), and water-soluble polymers (for cohesion and viscosity control). This composite structure ensures the cement maintains adequate sealing effectiveness while remaining sufficiently soft for ultrasonic removal when needed.
3Ease of operation
If the viscosity of the product is reduced for easy introduction into the canal, then the product flows better without air bubbles, but the cohesion and hold of the cement are weakened
Solution Approach 1:
The patent controls the viscosity of the dental product by adjusting the mass content of water-soluble polymers (0.5-5%) and the liquid medium (30-50%). This optimization ensures the product has low enough viscosity to flow easily into the dental canal without air bubbles, while maintaining sufficient cohesion for effective sealing.
Solution Approach 2:
The composite material combines calcium phosphate powders, organic acids, and water-soluble polymers in specific proportions. The water-soluble polymers provide viscosity control and cohesive properties, allowing the cement to flow easily during introduction while maintaining adequate hold and sealing effectiveness once set.
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 cement provides a stable, biocompatible seal with moderate hardness, facilitating easy removal and reprocessing, ensuring effective root canal filling and sealing while minimizing the use of toxic solvents.
Implementation Method 1
a powdery composition with a mass content of between 40% and 55% comprising at least one calcium phosphate and capable of forming hydroxyapatite in the presence of moisture
Implementation Method 2
said endodontic cement is brought into contact with a tool vibrating at an ultrasonic frequency
Data Source
Figure 1(A)~2(C)
AI summary
The present invention relates to a dental product for forming a hydroxyapatite-based endodontic cement in the presence of moisture, the cement formed being suitable for a simple retreatment operation with the ultrasonic tip.