Impression material being mixed together

An earmold (also spelled; ear mold, ear mould or earmould) is a device worn inserted into the

ear An ear is the organ that enables hearing and, in mammals, body balance using the vestibular system. In mammals, the ear is usually described as having three parts—the outer ear, the middle ear and the inner ear. The outer ear consists of ...

for sound conduction or

hearing protection A hearing protection device, also known as a HPD, is an ear protection device worn in or over the ears while exposed to hazardous noise and provide hearing protection to help prevent noise-induced hearing loss. HPDs reduce the level of the no ...

. Earmolds are

anatomical Anatomy () is the branch of biology concerned with the study of the structure of organisms and their parts. Anatomy is a branch of natural science that deals with the structural organization of living things. It is an old science, having it ...

ly shaped and can be produced in different sizes for general use or specially cast from particular ear forms. Some users specify how hard or soft they want their mold to be, an audiologist can also suggest this. As a conductor, it improves sound transmission to

eardrum In the anatomy of humans and various other tetrapods, the eardrum, also called the tympanic membrane or myringa, is a thin, cone-shaped membrane that separates the external ear The outer ear, external ear, or auris externa is the extern ...

s. This is an essential feature to diminish feedback paths in

hearing aid A hearing aid is a device designed to improve hearing by making sound audible to a person with hearing loss. Hearing aids are classified as medical devices in most countries, and regulated by the respective regulations. Small audio amplifiers su ...

s and assure better intelligibility in noisy-environment communication. The main goal in wearing earmolds is to attain better user comfort and efficiency. Earmolds (and their tubes) often turn yellow and stiff with age, and thus need replacement on a regular basis. Traditionally, the job of making earmolds is very time-consuming and skillful; each one is made individually in a molding process. However, new digital ear laser scanners can accelerate this process.

Viscosity

The texture of the earmold can have low, medium, or high

viscosity The viscosity of a fluid is a measure of its resistance to deformation at a given rate. For liquids, it corresponds to the informal concept of "thickness": for example, syrup has a higher viscosity than water. Viscosity quantifies the inte ...

. The lower type of viscosity will be soft while the higher viscosity is firm. It is thought that a higher viscosity will lead to a better impression of the

ear canal The ear canal (external acoustic meatus, external auditory meatus, EAM) is a pathway running from the outer ear to the middle ear. The adult human ear canal extends from the pinna to the eardrum and is about in length and in diameter. Struc ...

while the lower viscosity may not fill in the ear canal as well. The type of viscosity to use is dependent on the person using the material and the type of viscosity they are most comfortable with.

Syringe or Pistol

Once the viscosity is chosen the person can then choose to use a pistol or syringe for pushing the earmold material in the ear. The syringes need the material mixed together until it is a singular color and then it can be pushed through the tube of the syringe. The plunger of the syringe will then be used to push the material into the smaller area. The pistol uses pre-measured impression material and requires the person to press the trigger lever for the impression material to come out. Before the impression material is set in the external auditory canal,

otoscopy An otoscope or auriscope is a medical device which is used to look into the ears. Health care providers use otoscopes to screen for illness during regular check-ups and also to investigate ear symptoms. An otoscope potentially gives a view o ...

needs to be performed to make sure the canal is free of

cerumen Earwax, also known by the medical term cerumen, is a brown, orange, red, yellowish or gray waxy substance secreted in the ear canal of humans and other mammals. It protects the skin of the human ear canal, assists in cleaning and lubrication, a ...

or any other foreign objects. With the impression material ready to use the clinician will want to put an otoblocker into the ear canal. This will help prevent material from reaching the

tympanic membrane In the anatomy of humans and various other tetrapods, the eardrum, also called the tympanic membrane or myringa, is a thin, cone-shaped membrane that separates the external ear from the middle ear. Its function is to transmit sound from the air ...

of the

middle ear The middle ear is the portion of the ear medial to the eardrum, and distal to the oval window of the cochlea (of the inner ear). The mammalian middle ear contains three ossicles, which transfer the vibrations of the eardrum into waves in the ...

. For the otoblocker to be put in appropriately the clinician will want to pull up on the top of the pinna so the otoblocker can be put past the second bend of the ear canal. With the otoblocker in place the impression material can now be used to fill in the external ear canal and the spaces and crevices of the outer ear. Pistol-gun_for_earmold

Earmold Material

With the impression material in place and set in the

the clinician can decide what type of earmold material would benefit the patient the most. The three types of earmold materials include: acrylic, polyvinyl chloride, and silicone. Each type of material has positives and negatives about them, for instance, acrylic can help older patients with dexterity issues as the earmold is hard so insertion and removal of the earmold is easier or a silicone earmold which is soft and is extremely useful for children because of how pliable the material is. Letting_the_earmold_impression_material_harden_in_the_external_auditory_canal

Letting_the_earmold_impression_material_harden_in_the_external_auditory_canal

Ear Scanning

Earmolds present a variety of challenges. They can be inconsistent, time consuming, or inaccurate. This is why, in the early 2000s, a new idea for determining the anatomical shape of the individual's ear canal began circulating. The

Navy A navy, naval force, or maritime force is the branch of a nation's armed forces principally designated for naval warfare, naval and amphibious warfare; namely, lake-borne, riverine, littoral zone, littoral, or ocean-borne combat operations and ...

often had issues with earmolds, for the fact that once the initial impression was taken, the impressions would have to be shipped to a

manufacturer Manufacturing is the creation or production of goods with the help of equipment, labor, machines, tools, and chemical or biological processing or formulation. It is the essence of secondary sector of the economy. The term may refer to a ran ...

before the

could be made. This made imperative

personal protective equipment Personal protective equipment (PPE) is protective clothing, helmets, goggles, or other garments or equipment designed to protect the wearer's body from injury or infection. The hazards addressed by protective equipment include physical, elec ...

often time consuming and difficult to obtain. This is why the Navy then began looking for universities to create an anatomical 3D model of the ear using a scanner. The idea was that these scans could be sent electronically to manufacturers almost instantaneously. Karol Hatzilias from

Georgia Tech The Georgia Institute of Technology, commonly referred to as Georgia Tech or, in the state of Georgia, as Tech or The Institute, is a public research university and institute of technology in Atlanta, Georgia. Established in 1885, it is part of ...

undertook inventing an ear scanner, which has since then been successfully integrated onto Naval ships. This technology has slowly been working its way into clinical settings. Many different companies have come up with their own version of ear scanning.

References

{{Authority control Hearing Audiology