Earmold Impressions Flashcards
Careful visualization of this area of the external auditory canal during otoscopy allows audiologists to identify the location of the second bend.
anterior canal wall
Ideally, the canal length of an earmold impression will reach this depth to supply all the necessary information on anatomy an earmold manufacturer requires.
2mm past second bend
Combines 1:1 polyvinyl-siloxane parts of paste
addition cured silicone
Dimethyl-siloxane paste mixed with hardener
condensation cured silicone
Dimethyl-siloxane paste mixed with hardener
methyl methacrylate
What is the primary reason for using high-viscosity impression material when making earmold impressions?
supplies max stretch of aperature
Which 4 case history questions must be asked immediately before every earmold impression is taken (even when you’re working with a well-established patient!)
Are you immunocompromised; have you ever had surgery on your ears; do you take blood thinners; do you have any allergies (silicone or lube ingrediants)
Which three case history questions must be asked immediately before every earmold impression is taken (even when you’re working with a well-established patient!)
Are you immunocompromised; have you ever had surgery on your ears; do you take blood thinners
Are you diabetic; do you cough easily; do you bruise easily
Do you use Q-tips; Do you take Heparin; Is the shape of your ear abnormal
Are you immunocompromised; have you ever had surgery on your ears; do you take blood thinners
To effectively assess the external auditory canal using diagnostic otoscopy, the audiologist may sit or stand. The viewing position and angle do not make a difference
false
Earmold impressions should not be taken when a perforation of PE tube is present
false
This type of otoblock allows the audiologist to create a longer impression of the external auditory canal with less patient discomfort.
Cotton otoblock that’s equal in size to the EAC entrance
You feel resistance during otoblock insertion suggesting you’ve chosen the correct size. If the resistance suddenly decreases as you move it more deeply in the canal it indicates…
the patients ear canal widens beyond the 2nd bend
Open jaw impressions
increases size of the aperature
where is the valley
behind helix crus
what does the valley become
helix lock for retention
why do we fill the valley
where helix lock goes
causes stability & retention of the earmold made
what does the crus help with
helps us align the tube orientation correctly
what does the concha bowl provide
stability and/or retention
keeps earmold from coming out of the ear and provides retention
antitragus
what is the isthmus
where canal begins to smallen, transition from cartilage to bone (bone is at or past second bend)
does the ear canal space change when we open and close our mouths
YES
how can you consider mandible movement
have PT open & close jaw while doing otoscopy
does the Length differ for superior and inferior measurements of the canal
YES
b/c TM is oblique
avg canal length in adults
25mm
Transition from cartilaginous to bony canal
isthmus
Distance from canal entrance to isthmus is
aprox. 10mm
acoustic seal area
aperture
why do we want a stretched aperature? what happens if we don’t
stretching makes a well fit earmold
if not, it is uncomfortable because the skin rubs against the plastic
two goals for earmolds
go 2mm beyond 2nd bend
stretch aperature
what is addition cured silicone
combines 1:1 polyvinyl-siloxane parts paste
what is condensation cured silicone
silicast
dimmethyl-siloxane paste mixed with hardener
what are the clinical applications of the 3 impression materials
what is methyl methaccrylate
powder and liquid
used when pt has silicone allergies
not used often
what is viscosity for
how easy the material flows before it cures
thickness
describe high viscosity
thick
resistance during flow
condensation cured silicone
stretches aperature
describe medium viscosity
some stretch to aperture
Addition-cured silicone or methyl-methacrylate
describe low viscosity
Runny, loose
Flows easily with little resistance
Will not alter anatomical structure of ear canal
Most suitable for devices requiring deep insertion
Addition cured silicone
Used for ear attenuation products & deep fitting HA’s
what is the importance of stretching the aperture
stretching this area for a well fit earmold
if we do not do this we get an uncomfortable earmold because the skin rubs against the plastic
what is stress relaxation
materials ability to return to its shape after removal
high stress relaxation
you can pull on it and it will pop back into shape and won’t change at all
ex of high stress
silicone
why it is superior
low stress relaxation
distorts as you pull it out of the ear
ex low stress
methyl methacrylate
what is contraction ratio
shrinkage over a 7 day period
little shrinkage
silicone
significant shrinkage
methyl mythacrylate
what is shore value
after cure hardness
stability in impression box
______ shore values are more likely to be damaged during shipping
low
high shore value
siliconel
low shore value
methyl methacrylate
Susceptible to heat; requires glue for shipping so it doesn’t distort during shipping
methyl methacrylate
what are the ear impression steps
infection control
case history
otoscopy
otoblock placement
taking the impression
otoscopy
What is the ideal length of EMI
Ideal placement is 2mm beyond the 2nd bend`
what size should foam block b
larger than entrance of canal because it compresses and create a tighter block down the canal
what size should cotton block be
about the same size as the entrance
what are the steps to confirm otoblock placement
1.Removal string should be in the center of the canal
2.For 2nd bend placements
Visualize the anterior canal bend
Apply gentle pressure to feel bone on anterior canal wall
3.Check for gaps b/w block and canal wall
4.Apply slight pressure to the center of block
It should not move!
what are open jaw impressions
Increases the size of the aperture for a snugger fit
Condyle of Mandible moves forward pulls on the anterior canal wall
single impresion open jaw
horizontal placement
bilateral impression placement
vertical in center of mouth
post impression treatment
apply pressure to wound for 10 minutes
use large cotton otoblock soaked in vasoconstrictor
recheck ear canal week later
refer as needed
