Which areas of the brain are more active in dental phobia: a systematic review

Functional magnetic resonance imaging (fMRI) is an imaging technique that shows the function and activity of the brain during a specific time. Different studies have used fMRI to detect the active brain regions in patient with dental phobia. However, there is no reliable and comprehensive overview about the topic. The aim of this systematic review was to investigate the evidence regarding the identification of the active brain areas in dental phobia.

The present review was conducted according to the PRISMA guidelines across different databases included Web of science, PubMed, Scopus, Embase, Ebsco, and gray literature in accordance with the following PICO framework: P: individuals with dental phobia; I: fMRI C: individuals without dental phobia, O: active brain areas. All the articles up to August 2024 were selected for the qualitative analysis according to inclusion and exclusion criteria. Risk of bias of included studies was evaluated using ROBINS-I V2 tool, investigating seven domains seven domains of bias, including confounding, selection of participants, measurement classification of interventions, deviations from intended interventions, missing data, measurement of outcomes and selection of the reported result.

Out of an initial 458 retrieved records, 10 articles were included in the review, the majority of which (90%) had moderate risk of bias. The studies examined adults with a history of dental phobia, representing various age groups and genders. Based on the findings of the selected articles, significant differences in the brain activities of patients with dental phobia compared to controls and individuals with other types of specific phobia were mainly observed in brain areas such as frontal regions, insula, subcortical structures -including the caudate nucleus and pallidum-, and parietal and occipital cortices. Moreover, some studies also highlighted differences in the temporal regions, auditory and somatosensory regions, and motor regions, as well as cerebellar areas.

This study shows that dental phobia is a psychological disorder linked to structural and functional brain changes. In addition, paying adequate attention to gender differences and varying responses to stimuli could lead to more precise and individualized treatment for dental phobia.