Hearing Loss In the Dental Practice: What's the Real Risk?

I’ve heard some dentists older than I am mention the importance of protecting our hearing early on. Human nature usually has us addressing a problem when it’s already a problem, not beforehand; we see that every day with our own patients. When it comes to our hearing though, what are the real risk factors in dentistry? How important is it for us to protect ourselves early on?

I recently spoke with audiologist Brian Fligor to find the answer. The question of whether or not dentists will experience noise-induced hearing loss has long been controversial. What I found out from him is that most of our instruments have sound energy of very high frequencies, typically between 8,000 to 16,000 Hz.

While research hasn’t shown a strong association between dentistry and hearing loss, the hypothesis has been that dentists may exhibit a type of hearing loss sensitive to frequencies higher than the range typically tested by conventional audiometry. The frequency range of conventional testing is between 250 to 8,000 Hz.

The bottom line is that our hearing is probably strongly affected by our occupational exposure, but the way hearing is tested misses the connection.

Studies show that dentists that have been practicing in an environment with these higher frequency exposures for 10 or more years have a higher hearing sensitivity when compared to an age-matched control group not exposed to noise occupationally. Tinnitus, or ringing in the ears in the absence of an external stimulus, is another common complaint of practicing dentists. This, unfortunately, cannot be tested by audiometry.

Hearing loss is dependent upon two factors: the first is how loud the sound is, while the second is how long you are exposed to it for. Dentists are exposed to these high-frequency noises in the dental office for extensive periods of time.

The threshold for noise-induced hearing loss risk is 85 decibels. The National Institute for Occupational Safety and Health recommends noise exposure levels stay at or below this level for eight hours per day. We are exposed to several pieces of equipment that are in excess of this level; what we need to do is evaluate the duration we are exposed to it for. Drills, scalers, and suction all fall above 85 decibels.

So what can we do to help decrease our occupational risk of future hearing loss? Brian’s recommendations are to locate the source of the noise and put controls into place to reduce the level to a safe one when possible, to monitor hearing annually to document any changes, and to use hearing protection devices during long exposure periods.

Have you ever had a patient ask you what the best floss is? In your head you’re probably thinking, “the one you use.” It’s the same with ear plugs. What are our options?

1. Off-the-shelf foam earplugs. These are easy to get and cheap to purchase. The problem is that they often block out too much sound and make it difficult to hear the things we still need to, like our assistants. Inability to hear during dental treatment poses its own set of risk factors. In addition, they aren’t exactly comfortable.

2. Non-custom noise-attenuation earplugs. These are also over-the-counter, and the cost is in the range of $20 a pair. They don’t block out as much noise as the cheaper foam plugs, but they are “one size fits all,” so they can be fairly uncomfortable or inserted incorrectly, much like the foam earplugs.

3. Custom fit noise-attenuation earplugs. An audiologist can take a silicone impression of your ear canal, or a digital scan, and fabricate custom-made earplugs for around $150  to 200. These reduce sound levels across the spectrum by the same amount as the over-the-counter ones for $20, but they’re custom made for you, and much more comfortable.

4. Electronic earplugs. These allow soft to modest-level sound to come in without dampening the sound at all while still reducing the damaging sounds by the necessary amount. These are going to cost you the most, but are the best for allowing “safe sound” in and keeping dangerous sound out at an appropriate level.

I recently had custom-fit noise-attenuating earplugs made for myself and my team. My thought was to make a moderate investment to vet out whether or not I can get myself into the habit of wearing them routinely. I may get a second pair of the electronic earplugs in the future if I haven’t found my new pair collecting dust on the shelf.

As in our own profession, prevention is key. If you want to avoid tinnitus and hearing aids in the future, pay attention to your surroundings. When you know you’re going to be in a procedure that will damage your hearing for a long period of time, consider the use of hearing protection. If you’re in the lab on the lathe or trimmer for a while, or if you’re prepping teeth for hours straight on one patient, it’s easy enough to pop in some ear plugs and extend the life of your existing hearing ability.

(Click this link for more dentistry articles by Dr. Courtney Lavigne.)

Courtney Lavigne, D.M.D., Spear Visiting Faculty and Contributing Author - http://www.courtneylavigne.com