title: Cortical activation resulting from the stimulation of periodontal mechanoreceptors measured by functional magnetic resonance imaging (fMRI).
abstract: OBJECTIVE
  To describe the normal cortical projections of periodontal mechanoreceptors.
  
  
  METHODS
  A device using von Frey filaments delivered 1-Hz punctate tactile stimuli to the teeth during fMRI. In a block design paradigm, tooth (T) 11 and T13 were stimulated in ten volunteers and T21 and T23 in ten other subjects. Random-effect group analyses were performed for each tooth, and differences between teeth were examined using ANOVA.
  
  
  RESULTS
  The parietal operculum (S2) was activated bilaterally for all teeth; the postcentral gyrus (S1) was activated bilaterally for T21 and T23 and contralaterally for T11 and T13. In the second-level analysis including the four teeth, we found five clusters: bilateral S1 and S2, and left inferior frontal gyrus, with no difference between teeth in somatosensory areas. However, the ANOVA performed on the S1 clusters found separately in each tooth showed that S1 activation was more contralateral for the canines.
  
  
  CONCLUSIONS
  One-hertz mechanical stimulation activates periodontal mechanoreceptors and elicits bilateral cortical activity in S1 and S2, with a double representation in S2, namely in OP1 and OP4.
  
  
  CONCLUSIONS
  The cortical somatotopy of periodontal mechanoreceptors is poorly described. These findings may serve as normal reference to further explore the cortical plasticity induced by periodontal or neurological diseases.
authors.affiliation: Department of Prosthodontics, Faculty of Dentistry, Saint Joseph University, Campus of Medical Sciences, B.P. 11-5076, Damascus Road, Beirut, Lebanon, pascale.habrehallage@usj.edu.lb.
authors.forename: P
authors.initials: P
authors.lastname: Habre-Hallage
authors.forename: L
authors.initials: L
authors.lastname: Dricot
authors.forename: L
authors.initials: L
authors.lastname: Hermoye
authors.forename: H
authors.initials: H
authors.lastname: Reychler
authors.forename: D
authors.initials: D
authors.lastname: van Steenberghe
authors.forename: R
authors.initials: R
authors.lastname: Jacobs
authors.forename: C B
authors.initials: CB
authors.lastname: Grandin
mesh_terms: D000328:Adult; D002540:Cerebral Cortex / Q000502:physiology*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008465:Mechanoreceptors / Q000502:physiology*; D010519:Periodontium / Q000502:physiology*