Earmold Impressions Flashcards
Does the valley of the ear become a helix lock for retention?
Yes
What is the valley?
The area right behind the crus
Does the crus align with tube orientation?
Yes
Does the concha bowl provide stability and/or retention?
Yes
Does the antitragus provide retention?
Yes
It keeps the earmold from coming out
Where is the isthmus?
Before the 2nd bend
About 10 mm into the canal
Where does cartilage change to bone in the ear canal?
At and past the 2nd bend
Is the isthmus placement consistent in all people?
Yes
How far do we want to go past the 2nd bend?
2 mm
Why do we want to go 2 mm past the 2nd bend?
For retention
What is aperture?
Acoustic seal area
Do we need to stretch the aperture to create the proper fit?
Yes
A loose hearing aid is actually more uncomfortable
Do you choose what kind of impression material to use based on how much you want to stretch the aperture?
Yes
Some stretch it more than others
What are the three kinds of impression material?
Addition-cured silicone
Condensation-cured silicone
Methyl-methacrylate
What is addition-cured silicone?
Combines 1:1 polyvinyl-siloxane parts of paste
This is the one we use in class
What is condensation-cured silicone?
Dimmethyl-siloxane paste mixed with hardener
Not as commonly used
What is methyl-methacrylate?
Powder and liquid
Pre-measured acrylic powder and liquid formulas are rapidly mixed together
Mainly used when someone has silicone allergies
What is viscosity?
Refers to how easily material flows before it cures
What is high viscosity?
Thick
Resistant to flow
Condensation-cured silicone
Stretches the aperture of the canal
What is medium viscosity?
Provides some stretch to aperture
Addition-cured or methyl-methacrylate
What is low viscosity?
Runny and loose
Flows easily
Will not alter the anatomical structure of the ear canal
Most suitable for devices requiring deep insertion
Addition-cured silicone
Doesn’t stretch the aperture very much
Is aperture stretching important for attenuation products and deep in canal impressions?
No
What is stress relaxation?
Materials ability to return to its shape after removal
What material is superior for stress relaxation?
Silicone
Methyl-methacrylate’s shape can distort during removal (low stress relaxation)
What is contraction ratio?
It refers to shrinkage over a 7-day period
How much will silicone shrink (contraction ratio)?
0.1-0.7%
How much will methyl-methacrylate shrink (contraction ratio)?
3%
What is shore value?
It refers to the after-cure hardness
Lower shore values are likely to be damages during the shipping process
What is the shore value of silicone?
High
What is the shore value of methyl-methacrylate?
Low and is susceptible to heat
Requires being glued to box for shipping
What are the mandatory case history questions before earmold impressions?
Immunocompromised or diabetes?
Blood thinners?
History of ear surgery?
Allergies to silicone or nut oils?
Should you sit down while performing otoscopy?
Yes
What should you visualize during otoscopy?
Pinna, TM, and anterior canal wall
Why do you want to visualize the anterior canal wall?
It will help us guide down the otoblock
Should you pay attention to the vagus nerve activity?
Yes, it may impact impression taking
May make them cough or gag
Should you identify any congenital malformations or surgical signs during otoscopy?
Yes, could be a widening after the 2nd bend
Should you document any pre-impression abnormalities in the medical record?
Yes
What are some of the things you should document in the medical record?
Cerumen
Active infection
Prolapsed canal (exostoses and osteoma)
Collapsing canal
Significant jaw movement
Things that require precautions (perf, malformation, thick hair growth)
Should you note the ear canal direction during otoscopy?
Yes
Awareness of the variety shapes, textures, and sizes increases efficiency and safety
Should you pull up and back (down for peds) on the pinna during otoblock insertion?
Yes
Should you pull up and back (down for peds) on the pinna during the ear mold impression?
No
What are the three types of canal blocks?
Foam otoblock, cotton block, and pressure release block
What is a pressure release block?
It has a clear tube in it that is open at one end
It allows air between the otoblock and the TM to release through the tube
What are some benefits of a cotton block?
Provides more information on the anatomy of the ear canal
Easier to modify
It is easier to confirm block immovability
Is foam more abrasive than cotton?
Yes
How big should a foam block be?
Just bigger than the ear canal opening
How big should a cotton block be?
The same size as the opening
What extra precaution should you take if you have a patient with a perf?
Ensure there are no gaps between the block and the canal wall
What should you be cautious of with a patient with PE tubes?
Aggressive block depth may cause pain
What should you be cautious of with a patient with a widening canal/mastoidectomy?
May require more than one block
What is a sign of a widening canal?
If insertion beyond isthmus becomes easier
How do you confirm block placement?
Removal string is at the center of the canal
Visualize anterior canal bend (2nd bend placement)
Apply slight pressure to feel bone on anterior canal wall (2nd bend placement)
Check for gaps
Should not move with slight pressure
Do open jaw impressions increase the size of the aperture for a snugger fit?
Yes
Condyle of the mandible moves forward and pulls on the anterior canal wall
How should you place the block in the mouth for a single impression?
Place in mouth horizontally on the side of the impression
How should you place the block in the mouth for a double impression?
Place vertically in the center of the mouth
What are some benefits of a spleen pad?
Maintains temperature
Reduces risk of health hazard to audiologists following repeated absorption of chemicals into the skin
Reduces risk of contaminating material
Should you wear medical gloves when hand mixing?
No
How should you dispense the impression material?
Keep the tip embedded in the material so it will flow in an outward direction
What should you do with the syringe after dispensing the material?
Remove the hardened silicone
Wipe down with disinfectant
What is a precaution you should always take when taking impressions?
Hold the string
Should you fill the canal slowly?
Yes
To avoid the otoblock moving deeper
What is the last step of impression making?
Use a level marking
How should you remove the impression?
Wiggle it to release pressure seal
Remove from under antihelix and twist forward
When should you do otoscopy?
Before and after impressions
What should you do if someone is bleeding after an impression?
Apply pressure to wound for 10 minutes
Use a large cotton otoblock soaked in a vasoconstrictor (afrin)
Recheck heath of ear one week later
What are some rules to check is an impression is good?
Are there concentric circles?
Is the valley filled?
Is the concha cymba filled?
Is the concha cavum filled?
