Researchers identify why people fear the dentist

Millions of people around the world are afraid of visiting the dentist. One of the main reasons is the sharp, high-pitched whine of the dental drill. Researchers at Osaka University have, for the first time, studied this problem scientifically and found that it is not just the loudness but the quality of the sound that triggers fear, according to the Acoustical Society of America.

The study was led by dentist Tomomi Yamada, who observed that patients frequently flinch at the high-frequency, whistle-like noise of the drill. Despite its prevalence, even dentists had not systematically investigated the sound’s nature.

To understand how the noise is produced, the researchers conducted large-scale aeroacoustic simulations using one of Japan’s most powerful supercomputers. Dental drills operate using compressed air and spin up to 320,000 revolutions per minute, creating complex turbulent airflows.

The simulations allowed visualization of air movements inside and around the instrument—revealing the exact source of the sharp whine. However, simply reducing the volume is not enough to solve the problem.

“The key is not just to make the sound quieter, but to improve its quality,” says Yamada.

The study also examined how different groups perceive the sound. High-frequency noises up to 20 kHz affect adults and children differently. Tests showed that children perceive these sounds as louder and sharper than adults do.

“This means that children’s fear of dental procedures is not purely psychological—their hearing actually makes these sounds more unpleasant,” explains Yamada.

To address the issue, researchers plan to optimize the shape of the drill’s cutting blades and air vents, aiming to reduce unpleasant noise without compromising efficiency.

The next step involves collaboration with manufacturers. After ensuring safety and durability through rigorous testing, the technology could be commercially implemented. If successful, future dental offices—especially for children—may become much less intimidating.