title: Increased pain sensitivity to intraoral capsaicin in patients with atypical odontalgia.
abstract: OBJECTIVE
  To use 2 well-characterized stimuli, the intraoral capsaicin model and the "nociceptive-specific" electrode, to compare superficial nociceptive function between patients with atypical odontalgia (AO) and matched healthy controls. Furthermore, the authors aimed to describe the sensitivity, specificity, and positive predictive values (PPV) of the techniques if group differences could be established.
  
  
  METHODS
  Thirty-eight patients with AO and 27 matched healthy controls participated in this study. Thirty microliters of 5% capsaicin was applied to the gingiva on the left and right sides of all participants as a pain-provocation test. The participants scored the capsaicin-evoked pain continuously on a 0-to-10 visual analog scale (VAS). Furthermore, individual electrical sensory and pain thresholds to stimulation with a "nociceptive-specific" electrode on the facial skin above the infraorbital or mental nerve were determined.
  
  
  RESULTS
  AO patients had higher VAS pain scores for capsaicin application than healthy controls (ANOVA: F > 4.88; P < .029). No differences between the painful sides and the nonpainful sides of the patients were found (ANOVA: F < 1.26; P > .262). No main effects of group or stimulation side on the electrical sensory and pain thresholds were detected (ANOVA: F < 0.309; P > .579). Sensitivity was 0.51; specificity, 0.81; and PPV, 0.77 when a VAS value of > or = 8 for capsaicin-evoked pain was used.
  
  
  CONCLUSIONS
  AO patients show increased sensitivity to intraoral capsaicin but normal sensitivity to "nociceptive-specific" electrical stimulation of the face in an area proximal to the painful site. The use of the intraoral pain-provocation test with capsaicin as a possible adjunct to the diagnostic workup is hampered by the only moderately good sensitivity and specificity.
authors.affiliation: Department of Clinical Oral Physiology, School of Dentistry, University of Aarhus, Aarhus, Denmark. lbhansen@odont.au.dk
authors.forename: Lene
authors.initials: L
authors.lastname: Baad-Hansen
authors.forename: Thomas
authors.initials: T
authors.lastname: List
authors.forename: Troels Staehelin
authors.initials: TS
authors.lastname: Jensen
authors.forename: Peter
authors.initials: P
authors.lastname: Svensson
mesh_terms: D000704:Analysis of Variance; D002211:Capsaicin; D016022:Case-Control Studies; D004558:Electric Stimulation; D005260:Female; D006801:Humans; D006930:Hyperalgesia / Q000175:diagnosis*; D008297:Male; D008875:Middle Aged; D010147:Pain Measurement; D017288:Pain Threshold; D012680:Sensitivity and Specificity; D014098:Toothache / Q000503:physiopathology*; D014276:Trigeminal Nerve / Q000502:physiology
chemical_list: D002211:Capsaicin