Shear-Thinning Plaque Indicator Gel for Controlled Dental Application
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Solution Overview
Problem
Existing oral care compositions that reveal plaque are messy and difficult to use, as the dye can color not only the plaque but also other mouth areas, towels, and surfaces.
Innovation Solution
Development of a plaque indicator gel with specific rheological properties, characterized by a Herschel-Bulkley model, allowing for controlled application and retention on teeth, using a pen-type dispenser, which is shear-thinning and has a yield stress of 10 to 230 dynes/cm², viscosity of 3 to 500 poise, and flow index of 0.4 to 0.6, reducing dye usage and messiness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a liquid plaque indicator composition is used, then the dye can easily be applied and spread, but the application becomes messy and the dye colors lips, gums, tongue, towels and countertops
Solution Approach 1:
The patent changes the physical state parameter of the plaque indicator from a liquid to a gel form. This parameter change allows the composition to be applied controllably like a liquid but retained on the teeth like a solid, preventing messiness and unwanted staining while maintaining ease of application. The gel formulation with specific rheological properties (yield stress of 10-230 dynes/cm², viscosity of 3-500 poise, flow index of 0.4-0.6) enables this dual behavior.
2Duration of action of stationary object
If the viscosity of the gel is increased to improve retention on teeth, then the gel stays on longer for plaque absorption, but the gel becomes difficult to dispense and spread evenly
Solution Approach 1:
The patent employs a non-Newtonian shear-thinning gel formulation where the viscosity dynamically changes based on applied stress. At rest (low shear stress), the gel has high viscosity for retention on teeth. During application (high shear stress from dispensing and spreading), the viscosity decreases to allow easy flow and even distribution. This dynamic viscosity adjustment resolves the contradiction between retention and ease of application.
Solution Approach 2:
The patent utilizes rheological parameter changes in response to shear stress. The gel exhibits shear-thinning behavior characterized by a flow index of 0.4-0.6, meaning viscosity decreases as shear rate increases. This parameter change allows the gel to be easily dispensed and spread during high-shear application, then maintain high viscosity for prolonged retention on the teeth after application.
3Measurement precision
If more dye is added to improve plaque visibility, then the plaque can be more easily seen, but the staining of lips, gums, and other surfaces increases
Solution Approach 1:
The patent changes the physical state from liquid to gel, which alters the delivery and retention parameters of the dye. The gel formulation allows for controlled, localized application that remains on the teeth surface, improving plaque visibility while reducing the spread of dye to surrounding areas. The rheological properties (yield stress and viscosity) control the dye's movement and retention, enabling effective plaque detection with reduced unwanted staining.
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 gel allows for efficient, controlled, and even application, reducing mess and user effort, effectively revealing plaque for brushing while minimizing staining of teeth, lips, and gums, with user testing confirming ease of use and effectiveness.
Implementation Method 1
The gels of the invention are shear-thinning, meaning that the viscosity of the gel decreases in accordance with the Herschel-Bulkley Model as more force is applied (shear stress)
Implementation Method 2
The Herschel-Bulkley (HB) model is a generalized model of a non-Newtonian fluid, in which the strain experienced by the fluid is related to the stress in a non-linear way
Data Source
AI summary
The invention provides an orally acceptable plaque indicator gel comprising a dye in sufficient concentration to visibly stain plaque upon application, optionally for use in combination with an orally acceptable plaque removal gel comprising an antiplaque agent in sufficient concentration to remove plaque and or kill bacteria upon application, in each case the gel having a specific viscosity permitting efficient application using a pen dispenser, as well as reduced dye or antiplaque agent concentration, together with methods of using the same.