By Barry Keate
For years people have told me that visiting the dentist makes their tinnitus worse -- or better. As I've listened to their stories and asked many questions, clear patterns have emerged.
Some of the suspects are obvious. For example, drill noise and ultrasonic plaque removal both involve sustained sound that can cause or aggravate tinnitus. On the other hand, a trip to the dentist can resolve some conditions, such as abscesses and impacted wisdom teeth, which contribute to tinnitus.
Let's look at several ways in which tinnitus and your dentist visit may be related. As we'll see, the good news is that there are safer alternatives to the dental equipment, materials, and procedures which can cause or worsen tinnitus.
The high-pitched noise of dental drills is the most prominent way tinnitus can be caused or worsened. When the dentist is drilling in teeth, the sound is transmitted by bone conduction directly into the inner ear. It sounds much louder than it normally would because bone conduction has essentially no loss of intensity over short distances.
Some difficult procedures including tooth extraction and others where drilling is intense and long-term can cause noise damage to the cochlea. Wearing earplugs in this case will not be helpful; it will not prevent the damaging sound from reaching the cochlea. Anesthesia will also not be helpful as the damage will continue even though the patient is unconscious.
Dr. Jack Vernon, of the Tinnitus Center at Oregon Health Sciences University (OHSU), states that the best way to avoid hearing loss and tinnitus is to ask the dentist to drill in short spurts. Drill for five seconds then stop for ten seconds, drill for five seconds and stop for ten seconds, and so on. “The exacerbation of tinnitus by sound is a time-intensity function and by reducing the time of each drilling episode, the degree to which this kind of insult will influence the ears is also reduced.” (1)
Ultrasonic Plaque Removal
Ultrasonic cleaning tools for plaque removal can also be a cause of noise-induced hearing loss and tinnitus. These tools operate at a frequency of 12,000 to 15,000 Hz and emit bursts of high intensity sound that lasts for about ¼ to ½ second. Many people have complained of tinnitus due to these instruments.
Many technicians, if asked, will clean patients’ teeth with mechanical scaling implements. I have been having my teeth cleaned this way for many years as the ultrasonic devices were worrisome and also were very uncomfortable for me.
Dentists with Tinnitus
High-speed drills affect dentists much more than their patients. Dentists who work with high-speed drills for year after year in their practice are much more likely than those in other professions to acquire hearing loss and tinnitus. Estimates range from a low of 30% of dentists to a high of 100%.
One study conducted in Italy in 2012 compared hearing loss in general dental practitioners (GDPs) and general medical practitioners (GPs). Results were that 30% of GDPs had hearing impairment compared to 15% of GPs. (2)
On the other hand, Dr. Jack Vernon of OHSU reports that a dentist patient of his surveyed all the dentists in Oregon, Washington, Idaho and Northern California. He found that all who had purchased a high-speed drill, which became available in 1955, had high frequency hearing loss and tinnitus. (3)
“Most of the current high-speed hand pieces, such as high-speed drills and scalers used by dental professionals are between 90 and 100 decibels,” says Robert Folmer, PhD, a study leader on hearing loss and high-speed dental tools. “That’s the equivalent of a gas lawnmower or other power tools, which are loud enough to cause hearing loss over time.” (4)
None of the 54 dental schools nationally are known to require dental students to wear ear protection while treating patients and very few dental professionals wear earplugs.
Abscesses, Impacted Wisdom Teeth and TMJ
It has been reported that tooth abscesses or impacted wisdom teeth can cause tinnitus. (5) In such cases further dental work may cure the condition. Other times the tinnitus will gradually fade over time. One way this can occur is by aggravation of existing Tempero-Mandibular Joint (TMJ) dysfunction. Infection in the tooth or impacted wisdom teeth can cause inflammation that affects the TM joint.
TMJ dysfunction can be treated by dentists who specialize in the condition. They begin by fitting a mouth guard that aligns the lower jaw with the skull. When needed, more advanced, non-invasive therapies are developed to relax the muscle tissues.
There have been isolated cases of bilateral sensorineural hearing loss and tinnitus that occurs following dental surgery to remove impacted wisdom teeth. (6)
Another way that tinnitus can be caused is by the prolonged neck bending that occurs during dental surgery. This is referred to as somatic tinnitus and happens when bodily signals due to muscle strain can influence normal auditory pathways.
Unconsciously clenching the jaw or grinding the teeth is known as bruxism. This is one of the primary causes of TMJ dysfunction and often leads to tinnitus. It is a habit, which can be broken, not a reflex chewing activity. It can originally be caused by a number of conditions including allergy, trauma or high stress. Once bruxism becomes a habit, the original stimulus can be removed and the bruxism will continue.
Bruxism can also be treated with mouth guards, much like TMJ therapy. Further treatments may involve biofeedback or hypnotherapy to promote relaxation.
Mercury Amalgam Fillings
Dental amalgam fillings are commonly referred to as “silver fillings.” However, they contain approximately 50% mercury and only about 25% - 35% silver. Mercury is a neurotoxin and leads to numerous neurological problems including hearing loss and tinnitus.
There is a great debate about the safety of mercury amalgam fillings. The American Dental Association insists they are inert and safe. However, many researchers have found undeniable evidence that these fillings outgas mercury vapor and people inhale it, whereby it is absorbed into the body.
The World Health Organization proceedings of 1991 concluded the average person in the industrial world with an average number of amalgam fillings and no occupational exposure to mercury would absorb, on average, 10 micrograms of mercury per day from the fillings, with a high of 17 micrograms per day. For a 170 lb man, the maximum allowable dosage of mercury is 7.5 micrograms per day, Many scientists think even this allowable dosage is much too high.
Composite resin fillings are a common alternative to mercury amalgam. These are made of an acrylic resin and can be color-matched to the surrounding teeth. They are much more attractive than the silver-colored mercury fillings. They are a little more expensive but do not emit mercury vapor or other neurotoxins.
(1) From Questions and Answers, Reprinted from Tinnitus Today, June 1998.
(2) Messano GA, Petti S. General Dental Practitioners and Hearing Impairment, J Dent. 2012 Oct;40(10):821-8.
(3) From Questions and Answers, Reprinted from Tinnitus Today, June 1999.
(4) Folmer, R. Hearing Loos and High-Speed Dental Drills. http://www.medicalnewstoday.com/releases/49678.php
(5) Tinnitus: Theory and Management, J.B. Snow, ed. (2004) pp 115-7.
(6) Wilson RH, Witkowski CE, Wilson AA. Bilateral Idiopathic Sensorineural Hearing Loss Following Dental Surgery. J Am Acad Audiol. 2009 Mar;20(3):180-6.