Over the past few years I have found that I don’t seem to hear as well as I used to. My office staff would laugh at this statement, because it seems I hear every little conversation and happening in the office.  The problem arises when I am at an event with background noise, especially during the social hour before our general meetings. I find myself having to read lips during a conversation because the background noise drowns out the voice of the person that I am speaking with.

 

I made an appointment to have my ears checked fully expecting to come out with an aid in each ear.  I discovered that my hearing was very good with the exception of a very small frequency band that just happens to coincide with the background noise that occurs with multiple conversations.

“Occupational hearing loss is a form of acoustic trauma caused by exposure to vibration or sound. Sound is heard as the ear converts vibration from sound waves into impulses in the nerves of the ear”, according to Maryland Medical Center website, http://www.umm.edu/.

Sounds above 90 decibels (dB, a measurement of the loudness or strength of vibration of a sound), particularly if the sound is prolonged, may cause such intense vibration that the inner ear is damaged.

A general rule of thumb is that if you need to shout to be heard, the sound is in the range that can damage hearing.

Some jobs, such as construction, airline ground maintenance, farming, and jobs involving loud music or machinery, carry high risk for hearing loss.  In the U.S., the maximum job noise exposure is regulated by law. Both the length of exposure and the decibel level are considered. If the sound is at or greater than the maximum levels recommended, protective measures are required.

There are many causes of hearing loss. They can be divided into two main categories:

CHL is often reversible -- SNHL is not. People who have both forms of hearing loss are said to have mixed hearing loss.

I borrowed a decimeter and measured sounds in several dental offices and found that the High Speed Handpiece generated noise around 88-92 dB at working distance and over 100db at 6 inches from the source. The high volume evacuation was at 85 dB and a model trimmer trimming stone registered 92 dB.

According to Milagros Rios-Walker of Audiology Diagnostic Clinic at Westlake, my problem is a common one. Even though I have mild hearing loss beyond the 3000 cycles per second to 8000 cycles per second (high frequency range), “… it makes hearing in a crowd difficult because the “k”, “t”, “s”, and “th” sounds are difficult to distinguish from the many frequencies emanating from many sources of background noise”, according to Rios-Walker.

 

It seems that the cilia in the cochlea are damaged from long-term loud noises resulting in permanent hearing losses.

 

As in dental health, prevention is the key to health. If you haven’t had your hearing checked lately, I encourage you to do so. In addition, an awareness of the noise in our work environment is something that our profession needs to take a closer look at. Based on the noise levels I recorded in dental offices with the decimeter, it is clear that some damage will occur if protection is not utilized.  Have a safe and Happy New Year.