Capstone DesignCapstone Design

Auto Dispensing Prophy AngleAri KatzBrendan LaBrecqueStefan MagMatt RaoNick Starno

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Capstone Design

• The duration of the average cleaning is approximately 5 - 10 minutes• Dentifrice is reloaded up to one time per tooth (32 times) during cleaning• Between 50-100% of a container of dentifrice is used per patient

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The Cleaning Process

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DoriotHandpiece

DisposableProphy Angle

Dentifrice(“Prophy Paste”)

Capstone Design

Purpose

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Problem Statement:The amount of time a hygienist spends in an awkward position can be reduced and the dental cleaning procedure can be made more efficient.

Objective: Integrate a dentifrice dispensation system into a disposable prophy angle to simplify the process and reduce the overall time of the procedure.

Capstone Design

Benefits• Allows cleaning to become one continuous process• Reduces the duration of the cleaning• Increases cleaning efficiency in hard to reach areas• Reduces materials and sterilization processes

required for packaging• Improved ergonomics

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Capstone Design

Dentifrice Characteristics• A two-phase visco-elastic material comprised

of abrasives, binders, humectants, and other agents– Viscosity: >300 Pa*s; Re<1– Does not behave as a fluid– Composed of solid particles – Abrasive– Solid particles break down

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Before Use After 15 Seconds

Capstone Design 6

Existing Patents

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Capstone Design

Design RequirementsRequired Systems

– Dispensation Mechanism– Drive Mechanism– Dentifrice Storage

• Size – must interface with standard handpiece, fit in any patient’s mouth, and maintain ergonomics.

• Reliability & Ease of Use – must continuously dispense dentifrice at an acceptable rate or allow user control.

• Safe and Sterile – must use biocompatible materials, can’t generate excessive heat, and must be manufactured to allow for sterilization processes.

• Low Cost – currently the cost of a container of dentifrice and a disposable prophy angle is around 40 cents.

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Capstone Design

Initial Designs

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• Simple Design• Rifled Tube Integrates all Required

Systems• Orifice Restricts Flow Rate

• Spring Auger Drive Mechanism• Clutch Enabled User Control of

Dispensation

Capstone Design

Test 1 – Auger DispensationObjectives:

– Investigate the feasibility of using an auger as a dispensation mechanism

– Establish a correlation between pitch and volumetric flow rate

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Dremel Tool

Medium Grit

Dentifrice

Test Fixture

Scale

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Capstone Design

Test 2 – Plunger Dispensation

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Objectives: – Investigate the feasibility of using

a plunger as a dispensation mechanism

Plunger

Weight

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Capstone Design

Test 3 – Orifice Constriction

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Weight Scale

Dremel Tool

Test Configuration

with Taper

Objective: – Determine how much a

reduction in orifice size restricts the flow of dentifrice

AXAY

Capstone Design

Test 4 – Bend Radius

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Dremel Tool

Bent Tube Fixture

Dentifrice Displacement

Scale

Objectives: – Determine the feasibility of transporting dentifrice

around a 90º bent flow path.

Capstone Design

Test Conclusions

• Auger or reservoir must be rotating relative to the other

• No plunger mechanism

• Higher pitch yields higher velocity and force

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• No constrictions• Effect of bend in

flow path is minimal

Capstone Design

• Auger dispensation• Enables user control• Eliminates:

– Orifice constrictions– Bent Spring– Excess friction and heat

generation

Revised Designs

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Design 1

Design 2

Capstone Design

Design 1• Spring Auger• Bent Flow Path• Clutch System• User Control

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Design 1 Prototype Testing

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Pre-Test Post-Test

Capstone Design

• Straight Flow Path• Spring Auger• Brake System• User Control

Design 2

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Capstone Design 18

Design 2 Prototype Testing

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Capstone Design

Final Design

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Questions

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