Radiation Curable Dental Composites with High Filler Content

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Solution Overview

Problem

Current methods for producing dental restorations lack materials and processes that offer both aesthetic appeal and sufficient strength, with existing polymer-ceramic composites often falling short in durability and tooth-like aesthetics.

Innovation Solution

A radiation curable composition comprising a radiation hardenable component, a photo-initiator, and a filler material with particulates greater than 50% by weight, having a median diameter of over 0.3 micrometers, is used in an additive manufacturing process to form composite dental restorations, which are cured using actinic radiation, resulting in a near net-shape article with high flexural strength.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If polymer-ceramic composites are used for dental restorations, then aesthetic appeal is improved, but durability and strength are worsened

Engineering Contradiction:

Improveaesthetic appealVSAvoiddurability

Core Design Contradiction:

Ease of manufactureVSStrength

Solution Approach 1:

The patent changes the particle size parameter of ceramic fillers to greater than 0.3 micrometers median diameter, which improves the aesthetic properties of the restoration while maintaining structural integrity and durability through the specific size distribution and composition of the filler material

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses a composite material system combining polymer matrix with ceramic filler particles in a specific configuration, creating a material that exhibits both aesthetic properties from the ceramic surface and mechanical strength from the composite structure, achieving a balance between appearance and durability

Inventive Principle:

Principle #40Composite materials

2Productivity

If additive manufacturing is used to produce dental restorations, then manufacturing speed is improved, but material shrinkage and void formation are worsened

Engineering Contradiction:

Improvemanufacturing speedVSAvoidshrinkage and void formation

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The patent modifies the radiation curable composition parameters including viscosity control and filler particle size distribution to enable rapid additive manufacturing while minimizing shrinkage and void formation during the curing process, achieving both high productivity and manufacturing precision

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The additive manufacturing process creates a near net-shape copy of the final restoration directly from digital design, rapidly producing the restoration with high fidelity to the original 3D model while the specific material formulation prevents defects during this copying process

Inventive Principle:

Principle #26Copying

3Strength

If high filler content is used in radiation curable composition, then strength is improved, but viscosity increases making printing difficult

Engineering Contradiction:

Improveflexural strengthVSAvoidprintability

Core Design Contradiction:

StrengthVSEase of manufacture

Solution Approach 1:

The patent optimizes the particle size parameter distribution of the filler material with median diameter greater than 0.3 micrometers, which allows high filler content to be incorporated while maintaining lower viscosity for printability, achieving both high strength and ease of manufacture

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent applies different particle size qualities within the filler population, using a distribution where larger particles provide structural strength while the overall size distribution maintains flow characteristics suitable for printing, creating local variations in particle properties to achieve conflicting goals simultaneously

Inventive Principle:

Principle #3Local quality

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 process enables the rapid production of composite dental restorations with high fidelity to the original 3D model, achieving high flexural strength and maintaining aesthetics without substantial shrinkage or void formation, while being free from volatile components.

Implementation Method 1

selectively exposing a portion of the radiation curable composition to a source of actinic radiation to at least partially cure the exposed portion of the radiation curable composition

Methodology Applied

Scientific EffectPhotopolymerisation: Photopolymerisation

Data Source

PatentUS11553996B2Radiation curable compositions and composite articles made using an additive manufacturing process

Publication Date: 2023.01.17 SOLVENTUM INTELLECTUAL PROPERTIES CO

AI summary

A radiation curable composition including at least one radiation hardenable component, a photo-initiator, and a filler material having a population of particulates in an amount greater than or equal to 50% by weight of the printable composition. The population of particulates exhibits a median diameter (D50) of greater than or equal to 0.3 micrometer on a volume-average basis as determined using the Particle Size Test Method, and the radiation curable composition exhibits a viscosity of less than or equal to 150 Pa s when measured using the Viscosity Test Method. A method, apparatus, and systems for producing composite articles by selectively exposing a portion of the radiation curable composition to a source of actinic radiation to at least partially cure the exposed portion of the radiation curable composition, thereby forming a hardened layer, preferably by an additive manufacturing process such as stereophotolithography, are also described. The composite articles may include composite dental restorations.