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TOKYO, Japan: The sound of a dental drill or suction system evokes a feeling of fear in almost every tenth dental patient. New findings presented by Japanese researchers at a recent neuroscience meeting in the US have revealed new insights into how the brain of anxious patients may react during treatment.
Using functional magnetic resonance imaging, a neuroimaging procedure to measure brain activity, the researchers found stronger activity in the left caudate nucleus in anxious patients when playing them sounds of various dental instruments. When neutral sounds, like a French horn or pure tone, were played, however, activity in this region was found to be significantly lower.
No significant neural activity was detected when the same sounds were played to a control group of non-anxious patients. Instead, these patients showed stronger brain activity in the right and left superior temporal gyri, a part of the brain usually associated with auditory processing and other neural functions.
“Recent studies have indicated that the basal ganglia, including the caudate nucleus, may play a role in learning and memory functions. The subjects in the dental fear group therefore may be receiving feedback from memories of sounds of dental treatment,” researcher Hiroyuki Karibe from the Nippon Dental University’s Department of Pediatric Dentistry in Tokyo suggested. He said that the findings, which have not been published yet, could be applied to assess the effectiveness of conventional interventions for dental fear, such as cognitive behaviour therapy.
The study is the first to have measured how the sounds of dental instruments relate to brain activity. It confirms the assumption that dental anxiety is mainly due to reasons other than the fear of experiencing pain through surgery.
