Ear mold impressions

Question 1

the valley becomes what and why?

Answer 1

the valley becomes the helix lock for retention

Question 2

the crus aligns with what?

Answer 2

the tube orientation

Question 3

the concha bowl provides what?

Answer 3

-Concha bowl provides stability and/or retention
-Concha Cymba- sufficient fill for retention
-Concha cavum

Question 4

the antitragus provides what?

Answer 4

retention

Question 5

look at slide 3

Question 6

what is the average length of the ear canal

Answer 6

25 mm in adults

Question 7

the isthmus transitions from what to what

Answer 7

from cartilage to a bony canal

Question 8

the distance from the ear canal to the isthmus is what?

Answer 8

10 mm

Question 9

why does the visualization of the canal bend help

Answer 9

because it helps with otoblock placement

Question 10

look at slide 5

Question 11

additional cured silicone is made of ?

Answer 11

Combines 1:1 polyvinyl-siloxane parts of paste
-2 powders mixed together

Question 12

condensation cured silicon (like silicast) is made of

Answer 12

Dimmethyl-siloxane paste mixed with hardener
-take a scoop of scilicon material and mix it in your hand until it hardens are cures

Question 13

Methyl-Methacrylate is made of ?

Answer 13

-AKA “Powder and Liquid”
-Pre-measured acrylic powder and liquid formulas are rapidly mixed together
-powder and liquid and a nonsilicon

Question 14

what is viscosity ?

Answer 14

Refers to how easily the material flows before it cures
-refers to the thickness and how it flows to the syringe (def)
-each of those 3 materials to make ear mold impressions have different viscosity

Question 15

what does a high viscosity consist of ?

Answer 15

-Thick; provides resistance during flow
-Condensation-cured silicone (i.e., silicast)
-Stretches aperture of ear canal
-more energy is needed and pushing that aperature so we get a snug fit

Question 16

medium viscosity consist of ?

Answer 16

-Provides some stretch to aperture
-Addition-cured silicone or methyl-Methacrylate

Question 17

low viscosity consist of ?

Answer 17

-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
-doesn’t stretch the aperature too much
-used for deep fitting hearing aids

Question 18

what is stress relaxation and what does it consist of??

Answer 18

-Materials ability to return to its shape after removal
-Silicone is superior; methyl methacrylate’s shape can distort during removal (it has low stretch relaxation)
-high stress relaxation the shape doesn’t change if you stretch it
-low stress relaxation can change if you mess with it

Question 19

what is contraction ratio

Answer 19

-Shrinkage over a 7-day period
-Silicone will shrink 0.1-0.7% (doesn’t shrink)
-Methyl methacrylate will shrink 3% (it does shrink)

Question 20

what does shore value mean?

Answer 20

-it occurs AFTER cure hardness
-Lower shore values are likely to be damaged
during the shipping process
-Silicone has a high shore value
-Methyl methacrylate has a low shore value and is susceptible to heat; requires glue for shipping

Question 21

what is the first step to ear impressions ?

Answer 21

infection control!!
wash your hands and make sure all your equipment is disinfected

Question 22

what is the second step to ear impressions

Answer 22

case history

Question 23

what are the 4 questions you should ask during case history?

Answer 23

1)Infection risk: immunocompromised? Diabetes?
2)Bleeding risk: therapeutic blood thinner?
3)Potential ear canal malformations: History of ear surgery
4)Allergies: silicone, lubricant ingredients

Question 24

what is the 3rd step of ear impressions

Answer 24

otoscopy

Question 25

what should you do during otoscopy

Answer 25

-Thoroughly examine patient’s ear
-Sit down while performing otoscopy!
>Examination at eye level is needed to view full canal
1)Visualize Pinna, TM, and anterior canal wall
2)Pay attention to vagus nerve activity which may impact impression taking
3)Identify congenital malformations or surgical signs
4)Identify canal bend

Question 26

what are things we should write down when we see them

Answer 26

Document all pre-impression abnormalities in the medical record like:
1)Cerumen- significant quantity requires removal b/f impression
2)Active infection: drainage? bacterial or fungal? Inflammation ?
-this is a contraindication for EMI
3)Prolapsed canal (exostoses, osteoma);
Collapsing canal
-May limit depth; requires consideration of earmold material
4)Significant jaw movement during otoscopy to see if it changes
5)Requires precautions
-Perforation; PE tube
-Malformation- requires special precautions
-Congenital ear canal widening; stenosis;
-Surgical- Mastoidectomy
-Thick hair growth- may require trimming

Question 27

during otoscopy we should note what?

Answer 27

-During otoscopy note the ear canal direction
-Awareness of the variety of shapes, texture, & sizes increases efficiency and safety

Question 28

what is the 4th step in ear impressions:

Answer 28

otoblock placement
-Ideal placement is 2mm beyond the 2nd bend

Question 29

during ear mold impressions, do we pull the pinna to straighten the canal?

Answer 29

only when putting in the otoblock but not when where putting in the ear mold impression

Question 30

what is the purpose of canal block

Answer 30

Limits depth of impression material flow and supplies the resistance needed to fully fill canal

Question 31

what do cotton blocks provide ?

Answer 31

1)Provides more information on the anatomy of the ear canal
2)Easier to modify
-Can be tugged at to reduce the size
-Flattened out to better fill the entire canal space
3)It’s easier to confirm block immovability

Question 32

what can be provided in foam blocks?

Answer 32

1)Takes up more space in the ear canal
2)Does not modify easily
3)More abrasive; making it less comfortable for the patient

Question 33

what are things to consider when doing an otoblock insertion?

Answer 33

1)Choosing the otoblock size
-Foam block should be larger than entrance of external canal
-Cotton block should be about the same size as entrance
2)Lubricate block (be aware of potential allergies)
3)Insert slowly without touching canal wall