title: The anterior insula and anterior cingulate cortex are associated with avoidance of dental treatment based on prior experience of treatment in healthy adults.
abstract: BACKGROUND
  Fear concerning stressful medical or dental procedures is one of the major factors that distance patients from health care. Fear and avoidance of dental treatments can be shaped by a patient's prior experience with receiving dental procedures or by imagining the procedures.
  
  
  METHODS
  We performed two functional magnetic resonance imaging (fMRI) experiments to investigate the role of the anterior insula (aINS) and dorsal anterior cingulate cortex (dACC), which are both critical to threat perception, in dental avoidance. Dental avoidance based on both prior treatment experience and imagination was assessed using a customized questionnaire. In an fMRI task-based study, we investigated brain activation in 17 healthy participants when they viewed images depicting dental procedures that evoked a moderate degree of fear. Region-of-interest analysis was performed to assess the association between dental avoidance and aINS as well as dACC activation. In a resting state fMRI study, we investigated 18 healthy participants for the association between the intrinsic functional connectivity of the aINS and dACC and dental avoidance.
  
  
  RESULTS
  We found that (1) the participants showed a higher activation of the right aINS and bilateral dACC when they viewed images of dental procedures compared with the brain activation observed when they viewed scrambled images (p < 0.05 corrected for small volume and family-wise error). (2) The avoidance ratings based on prior experience of dental treatment were significantly positively correlated with the activation in the right aINS (r = 0.67, p = 0.003), right dACC (r = 0.65, p = 0.005) and left dACC (r = 0.63, p = 0.007). (3) The intrinsic functional connectivity between the aINS and the orbitofrontal cortex was positively correlated with the avoidance ratings based on experience (uncorrected p < 0.001).
  
  
  CONCLUSIONS
  The findings highlight prior experience of dental treatment as a predominant factor in shaping patients' avoidance behavior. Individual differences in threat perception may play a key role in the development of dental avoidance.
authors.affiliation: Department of Dentistry, School of Dentistry, National Yang-Ming University, No. 155, Sec. 2, Linong Street, Taipei, 11221, Taiwan, ROC. winzlin@ym.edu.tw.
authors.forename: Chia-Shu
authors.initials: CS
authors.lastname: Lin
authors.affiliation: Department of Dentistry, School of Dentistry, National Yang-Ming University, No. 155, Sec. 2, Linong Street, Taipei, 11221, Taiwan, ROC. sywu@vghtpe.gov.tw.|Division of Family Dentistry, Department of Stomatology, Taipei Veterans General Hospital, Taipei, Taiwan, ROC. sywu@vghtpe.gov.tw.
authors.forename: Shih-Yun
authors.initials: SY
authors.lastname: Wu
authors.affiliation: Department of Dentistry, School of Dentistry, National Yang-Ming University, No. 155, Sec. 2, Linong Street, Taipei, 11221, Taiwan, ROC. oolongtea@gmail.com.|Division of Endodontics and Periodontology, Department of Stomatology, Taipei Veterans General Hospital, Taipei, Taiwan, ROC. oolongtea@gmail.com.
authors.forename: Long-Ting
authors.initials: LT
authors.lastname: Wu
mesh_terms: D001362:Avoidance Learning / Q000502:physiology*; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000503:physiopathology*; D016854:Dental Anxiety / Q000503:physiopathology*; D003729:Dental Care / Q000009:adverse effects / Q000523:psychology; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D009434:Neural Pathways / Q000503:physiopathology; D009483:Neuropsychological Tests; D010775:Photic Stimulation; D012146:Rest; D014796:Visual Perception / Q000502:physiology; D055815:Young Adult