Researchers at Oregon Health and Science University, USA are looking into whether high-speed dental tools contribute to long-term hearing loss. According to Professor Robert Folmer, one of the study leaders, published research is mixed about whether high-speed dental tools contribute to noise-induced hearing loss over time.

“Over the years, we have seen dentists in the OHSU Tinnitus Clinic who were convinced that long-term exposure to sound from high-speed hand pieces contributed to their high-frequency hearing loss and tinnitus,” says the Associate Professor of Otolaryngology/Head and Neck Surgery, School of Medicine, and chief of clinical services at the OHSU Tinnitus Clinic, Oregon Hearing Research Center.

“These anecdotes, in combination with the research being divided about high-speed hand pieces playing a role in hearing loss, prompted our study. We hope the study is a good first step toward scientific evidence behind the anecdotes we've been hearing.”

Tinnitus, or ringing of the ears, can be constant or intermittent and can include buzzing, hissing or sizzling sounds. Many people experience momentary tinnitus, a high-pitched tone that lasts up to 30 seconds.

Acute tinnitus, however, can last days or weeks and is most commonly caused by exposure to loud noise such as music at a rock concert, power tools or gunfire. The subsequent ringing indicates damage to the tiny hair-like structures within the inner ear and if exposure to loud noise continues, permanent hearing loss is likely.

Most of the current high-speed hand pieces, such as high-speed drills and scalers used by dental professionals, are between 90 to 100 decibels, says Professor Folmer. That's the equivalent of a gas lawnmower or other power tools, which are loud enough to cause hearing loss over time. He adds that while hand pieces have actually become “quieter” over the years with the advent of modern technologies, very few dental professionals or students interviewed for the study so far wear earplugs to protect themselves from this noise.

The team will investige noise-induced hearing loss by conducting hearing tests with a portable audiometer, examining ear canals with an otoscope and asking participants to answer questions about occupational and recreational noise exposure. They also have measured the sound levels of different hand pieces while they're used on patients.

“We want to compare the hearing tests of dentists, dental assistants, and dental hygienists to those of dental students and people of comparable age in other professions,” says Professor Folmer. “We also want to examine whether there's a correlation between hearing thresholds and the amount of time that dental professionals are exposed to loud devices at work. And if dental professionals exhibit evidence of noise-induced hearing loss, can it be correlated with occupational or recreational noise exposure? Our hypothesis is that if dental professionals utilise hearing protective devices, they will exhibit less noise-induced hearing loss than dental professionals who do not protect their ears.”

So far, about 40 School of Dentistry professionals and students have had their hearing tested and more data is needed before any conclusions can be drawn.