Researchers at Oregon Health and Science University, USA are looking into whether high-speed dental tools contribute to long-term hearing loss.

‘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,’ said Professor Robert Folmer, one of the study leaders.

‘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. 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 investigate 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.