Researchers in Japan have been scanning people’s brains while playing them sounds of dentists drills and suction instruments. People who were scared of visits to the dentist showed marked differences in their brain responses to those who were more relaxed at the idea of a trip to the dentist.
During the study, the dentist, Karibe, asked volunteers to complete questions relating to their fear and then categorised them into high and low fear groups. The dentist then scanned the participants’ brain in a functional magnetic resonance imaging machine while playing them a series of sounds, including dental drills and suction tools.
“All of the participants were isolated in the fMRI room when they listened to the dental sounds, so we couldn’t see if they responded visibly or audibly to the dental sounds, but we could recognise their responses from their brain activity,” Karibe said.
People in the low-fear group were not overly anxious about dental work. When they heard dental sounds, parts of the brain known as the left and right superior temporal gyri responded more than when they heard neutral sounds. This, Karibe said, means that dental sounds triggered more activity in the primary auditory areas of the brain. Anxious people responded differently. Instead of a surge of activity in the auditory areas of their brain, Karibe said he saw a more intense response in a region called the left caudate nucleus, which may play a role in learning and remembering the sounds of the dental instruments.
About 10% of the population have severe anxiety surrounding trips to the dentist and many avoid visits until they have toothache or another emergency, such as an abscess. The behaviour can lead to a negative cycle of events, with patients becoming ever more afraid because emergency treatment can be more traumatic.
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