CAN YOU HEAR ME NOW?
terials similar to a dental impression.
While these earplugs offer a custom
fit, again, they are only designed to
reduce noise input. Musicians’ earplugs
are designed with small filters that
dampen down certain sound ranges
while amplifying others. So these are
not an ideal product for those of us in
A new earplug called the DI 15 was
introduced recently that is specifically
designed for use by dental health-care
workers. The DI 15 is a “smart” ear
protection technology fabricated with
a custom electronic circuitry that com-presses sound when the decibel levels
reach the dangerous point. The noise
reduction rating for the DI 15 is 25. The
compression stops when noise levels
fall back into a safer range.
In addition to compressing noise
levels as needed, dental professionals
can carry on a normal conversation
with patients and other staff members.
These earplugs are quite small and
powered by a tiny hearing-aid battery
that typically lasts approximately two
The DI 15 ear protector device is
quite small and fits discreetly into the
reduces sound by 7 dB and is not an
effective protective device.
create a physical barrier when inserted
correctly into the ear canal. However,
while effective in reducing damaging
noise levels, human speech is muffled
The three types of over-the-counter
earplugs are foam, molded polyurethane, and silicone. Foam earplugs are
single-use devices. The user needs to
roll the plug in the palm of the hand to
reduce the diameter and then insert
the device into the ear canal. The compressed foam expands to create a seal.
Molded polyurethane and silicone
earplugs can be used more than once
and can be cleaned between uses. None
of these devices is designed for a custom fit, so it is important to take care
in the installation process.
Earplugs are typically rated for
noise reduction. An NR 25 has the capacity to reduce the decibel levels by
25, while one rated at NR 33 will have
a greater capacity to reduce damaging
Custom-made earplugs can be
obtained from an audiologist. Impres-
sions are taken for each ear, using ma-
The web-based program, “It’s a
noisy planet: Protect their hearing, ”
from National Institutes of Health fo-
cuses on protecting the hearing of
children and adolescents but also con-
tains a wealth of practical advice that
is applicable to everyone. Before ex-
ploring our unique dental needs, here
are the universal precautions recom-
mended by the National Institute on
Deafness and Other Communication
• Know which noises can cause
damage (greater than 85
• Wear earplugs or other protective
• If you can’t reduce noise, move
away from it.
• Be alert to hazardous environmental noises.
• Protect the ears of children.
• Make family, friends, and
colleagues aware of hazardous
• Suspect hearing impairment?
Since noise will always be a part of
the dental environment, the most logical way to reduce the hazards of NIHL
is to work with equipment that is less
noisy and to use some form of direct
44, 45 Handpieces are
now made that are much quieter than
earlier models. Poorly maintained or
worn-out high-speed handpieces are
noisier. Daily maintenance will keep
equipment running smoother and
prevent handpieces from wearing out
37 Quiet compressors are
now available. Portable and mobile
dental units are now made with quieter
The other strategy is to use adequate ear protection every day, all day
44, 45 Very few clinicians receive
training about hearing protection
during school, so many are not aware
of their hearing protection options, and
some assume the noise is not damaging. Comfort, convenience, and efficacy
play a huge role in implementing a
hearing protection plan.
Cotton stuffed into the ear canal
is the spectrum where a person loses
the ability to hear high-pitched
36, 40 Hearing impairment
among dentists is being reported at
36, 39, 41 In addition,
hearing thresholds are high for
Only two studies specifically evaluated hearing loss issues among dental
hygienists. The hearing status of hygienists who had a high rate of ultrasonic scaler usage was compared to
hygienists who reported minimal use
of these devices. Testing was conducted using a pure tone audiometer. There
were no differences between the two
groups in hearing threshold levels, but
the high-usage group had hearing loss
at 3 kHz. While the findings are an
important start in understanding hearing loss among dental hygienists, the
study did not control for type or condition of ultrasonic unit, power level
control, or size, configuration, or diameter of the ultrasonic tip.
In a self-administered questionnaire, 40% of respondents with an average age of 56 reported hearing difficulty. Respondents with hearing
difficulty were twice as likely to report
high use of ultrasonic scalers. Over 90%
of those who reported hearing difficulty
related to power scaler usage had their
hearing loss confirmed by an audiologist.
43 While there may be a strong
correlation between ultrasonic usage
and hearing impairment, this study
also does not demonstrate causality.
The first 10 years of excessive noise
exposure are the most risky for developing NIHL. Since loss is cumulative,
reducing the risk is critical at any career
point, especially since high-frequency
tones are most important to understanding speech.
44 A standard audiogram provides a conventional hearing
threshold evaluation. Since dental
professionals are at increased risk for
high-frequency hearing loss, additional
tests such as high-frequency threshold
audiometry can help in the early detection of NIHL.
DI 15 ear protection correctly installed in the ear canal.