Dental Composite Thixotropy Control via Hydroxy Additives
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Solution Overview
Problem
Dental composites with high filler content face challenges in achieving optimal plasticity and low stickiness for improved handling and mechanical properties, as existing methods fail to effectively control thixotropy and stickiness, leading to inconsistent product quality.
Innovation Solution
The method involves adding pre-polymer fillers and hydroxy-functionalized additives in small proportions to dental composites, optimizing the balance of plasticity and stickiness while maintaining mechanical properties, by adjusting the texturing and stickiness parameters through specific formulations and testing methods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If high filler content is used to improve mechanical properties and reduce polymerization shrinkage, then wear resistance and fracture resistance are improved, but thixotropy and stickiness increase due to surface interactions
Solution Approach 1:
The patent changes the chemical composition parameters by introducing hydroxy-functionalized additives (component A2) that specifically interact with the oxidic filler particle surfaces. This modifies the surface chemistry to reduce polar interactions, thereby decreasing thixotropy and stickiness while preserving the high filler content needed for mechanical strength.
Solution Approach 2:
The hydroxy-functionalized additives act as intermediary substances between the inorganic filler particles and the polymer matrix. These additives mediate the surface interactions by forming a functional layer that reduces unwanted adhesion and thixotropic behavior, allowing high filler content to be maintained without compromising handling properties.
2Ease of operation
If filler content is adjusted to correct consistency, then flow behavior changes, but stickiness changes uncontrollably
Solution Approach 1:
Instead of adjusting filler content to control consistency, the patent changes the chemical composition by adding hydroxy-functionalized additives. This allows independent control of flow behavior through viscosity modification while the additive simultaneously controls stickiness through surface interaction, providing precise control over both parameters.
3Ease of operation
If soft composite formulation is used to improve flow behavior, then plasticity increases, but stickiness increases due to better flow
Solution Approach 1:
The hydroxy-functionalized additives serve as intermediary substances that decouple the relationship between flow behavior and stickiness. They allow the composite to maintain soft, flowable consistency while the additive layer on filler surfaces prevents excessive stickiness, breaking the direct correlation between plasticity and adhesion.
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 results in dental composites with improved flowability, reduced stickiness, and stable mechanical properties, ensuring consistent quality and enhanced usability, as demonstrated by the IG/IK quotient analysis.
Implementation Method 1
The desired high filler contents of inorganic fillers in particular bring a disadvantageous thixotropy into the system due to the surface interaction. Caused by the polar interactions between the oxidic filler particles (silicates), these forces can be partially temporarily disturbed under shear, and the composites are characterized by a structural viscosity.
Implementation Method 2
The urethane crosslinkers (TCD-di-HEA, HEMA-TMDI) usually form hydrogen bonds and thus lead to greater stickiness or firm consistency/plasticity.
Implementation Method 3
Caused by the polar interactions between the oxidic filler particles (silicates), these forces can be partially temporarily disturbed under shear
Data Source
AI summary
Adjusting, improving or optimizing usage properties of filler-containing flowable dental material with a measurement variable for adhesiveness and a measurement variable for texturing, plasticity or consistency, which are correlatively adjusted, is claimed. Independent claims are also included for: (1) determining optimized usage properties of flowable filler-containing dental composite material, comprising (A) determining texturing-, plasticity- or consistency value, (B) determining adhesiveness value, (C) forming quotient by dividing texturing, plasticity or consistency value by adhesiveness value, where the quotient is 2-5; (2) the filler-containing flowable dental material comprising an additive, which comprises silicon-containing compounds of formula (H-Y1-Z) (I), where the filler comprises glass filler or filler based on ground polymer, which is pre-polymerized with inorganic particles, preferably silicon dioxide, preferably splinter polymer or prepolymer-filler, and dental material exhibits the quotient of 2-5; and (3) a dental composition, obtained by the above method, comprising 65-75 wt.% glass filler, preferably barium-aluminosilicate glass, optionally 1-5 wt.% splinter polymer, 0.1-5 wt.% (I), 15-25 wt.% monomer, preferably urethane (meth)acrylate and 15-20 wt.% crosslinking agent, preferably (bis-(acryloyloxymethyl)tricyclo[5.2.1.0.sup.2,6]decane) or diurethane dimethacrylate. Y1 : O, S, CO, OSi(OR) 2R or R; Z : H, OH, SH, NH 2, COOH or COOR; R : C nH mO p; n : less than 10; m : less than 20; and p : less than 5.