Increased pain sensitivity to intraoral capsaicin in patients with atypical odontalgia.
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.
Baad-Hansen
Lene
L
Department of Clinical Oral Physiology, School of Dentistry, University of Aarhus, Aarhus, Denmark. lbhansen@odont.au.dk
List
Thomas
T
Jensen
Troels Staehelin
TS
Svensson
Peter
P
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
D002211:Capsaicin