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Capstone DesignCapstone Design
Auto Dispensing Prophy AngleAri KatzBrendan LaBrecqueStefan MagMatt RaoNick Starno
1 2 . 0 4 . 0 7
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
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
dt
dxA
dt
dVQ Slug
Capstone Design
Test 2 – Plunger Dispensation
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Objectives: – Investigate the feasibility of using
a plunger as a dispensation mechanism
Plunger
Weight
vD
Re
Re
64f
g
v
D
lfhLmajor 2
2
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
14
Design 1
Design 2
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