title: Different Brain Responses to Pain and Its Expectation in the Dental Chair.
abstract: A dental appointment commonly prompts fear of a painful experience, yet we have never fully understood how our brains react to the expectation of imminent tooth pain once in a dental chair. In our study, 21 patients with hypersensitive teeth were tested using nonpainful and painful stimuli in a clinical setting. Subjects were tested in a dental chair using functional near-infrared spectroscopy to measure cortical activity during a stepwise cold stimulation of a hypersensitive tooth, as well as nonpainful control stimulation on the same tooth. Patients' sensory-discriminative and emotional-cognitive cortical regions were studied through the transition of a neutral to a painful stimulation. In the putative somatosensory cortex contralateral to the stimulus, 2 well-defined hemodynamic peaks were detected in the homuncular orofacial region: the first peak during the nonpainful phase and a second peak after the pain threshold was reached. Moreover, in the upper-left and lower-right prefrontal cortices, there was a significant active hemodynamic response in only the first phase, before the pain. Subsequently, the same prefrontal cortical areas deactivated after a painful experience had been reached. Our study indicates for the first time that pain perception and expectation elicit different hemodynamic cortical responses in a dental clinical setting.
authors.affiliation: University of Michigan School of Dentistry, Ann Arbor, MI, USA Cariology, Restorative Sciences, and Endodontics, University of Michigan School of Dentistry, Ann Arbor, MI, USA.
authors.forename: A J
authors.initials: AJ
authors.lastname: Racek
authors.affiliation: Headache and Orofacial Pain Effort Lab, University of Michigan School of Dentistry, Ann Arbor, MI, USA Center for Human Growth and Development, University of Michigan, Ann Arbor, MI, USA.
authors.forename: X
authors.initials: X
authors.lastname: Hu
authors.affiliation: University of Michigan School of Dentistry, Ann Arbor, MI, USA Headache and Orofacial Pain Effort Lab, University of Michigan School of Dentistry, Ann Arbor, MI, USA.
authors.forename: T D
authors.initials: TD
authors.lastname: Nascimento
authors.affiliation: Headache and Orofacial Pain Effort Lab, University of Michigan School of Dentistry, Ann Arbor, MI, USA.
authors.forename: M C
authors.initials: MC
authors.lastname: Bender
authors.affiliation: University of Michigan School of Dentistry, Ann Arbor, MI, USA.
authors.forename: L
authors.initials: L
authors.lastname: Khatib
authors.affiliation: University of Michigan School of Dentistry, Ann Arbor, MI, USA Cariology, Restorative Sciences, and Endodontics, University of Michigan School of Dentistry, Ann Arbor, MI, USA.
authors.forename: D
authors.initials: D
authors.lastname: Chiego
authors.affiliation: University of Michigan School of Dentistry, Ann Arbor, MI, USA Cariology, Restorative Sciences, and Endodontics, University of Michigan School of Dentistry, Ann Arbor, MI, USA.
authors.forename: G R
authors.initials: GR
authors.lastname: Holland
authors.affiliation: University of Michigan School of Dentistry, Ann Arbor, MI, USA Cariology, Restorative Sciences, and Endodontics, University of Michigan School of Dentistry, Ann Arbor, MI, USA.
authors.forename: P
authors.initials: P
authors.lastname: Bauer
authors.affiliation: University of Michigan School of Dentistry, Ann Arbor, MI, USA Cariology, Restorative Sciences, and Endodontics, University of Michigan School of Dentistry, Ann Arbor, MI, USA.
authors.forename: N
authors.initials: N
authors.lastname: McDonald
authors.affiliation: Clinical Method Development, Colgate Palmolive, Piscataway, NJ, USA.
authors.forename: R P
authors.initials: RP
authors.lastname: Ellwood
authors.affiliation: University of Michigan School of Dentistry, Ann Arbor, MI, USA Headache and Orofacial Pain Effort Lab, University of Michigan School of Dentistry, Ann Arbor, MI, USA Center for Human Growth and Development, University of Michigan, Ann Arbor, MI, USA Biologic and Material Sciences, University of Michigan School of Dentistry, Ann Arbor, MI, USA adasilva@umich.edu.
authors.forename: A F
authors.initials: AF
authors.lastname: DaSilva
mesh_terms: D001294:Attitude to Health; D001921:Brain / Q000502:physiology*; D003071:Cognition / Q000502:physiology; D003080:Cold Temperature; D016854:Dental Anxiety / Q000503:physiopathology / Q000523:psychology; D003807:Dentin Sensitivity / Q000503:physiopathology* / Q000523:psychology; D004644:Emotions; D005071:Evoked Potentials / Q000502:physiology; D005260:Female; D006439:Hemodynamics / Q000502:physiology; D006801:Humans; D008297:Male; D010147:Pain Measurement / Q000379:methods; D058748:Pain Perception / Q000502:physiology; D017288:Pain Threshold / Q000502:physiology; D010474:Percussion; D017397:Prefrontal Cortex / Q000503:physiopathology; D012684:Sensory Thresholds / Q000502:physiology; D013003:Somatosensory Cortex / Q000503:physiopathology; D019265:Spectroscopy, Near-Infrared
keywords: clinical setting; dental pain; functional near-infrared spectroscopy; percussion; prefrontal cortex; somatosensory cortex