Prolonged gingival cold allodynia: a novel finding in patients with atypical odontalgia.

Objective: The aim of this study was to examine atypical odontalgia (AO) patients with extraoral quantitative sensory testing (EQST) and an intraoral mucosal cold test.
Study Design: Twenty-one subjects with AO and 18 control subjects underwent EQST for electrical and thermal pain and detection thresholds. Cold was applied to painful mucosal areas in AO patients and randomly in control subjects.
Results: Electrical pain thresholds were higher in AO patients than in control subjects in the same dermatome affected by the pain (P = .03), but no significant differences were observed in electrical detection thresholds and heat pain and detection thresholds at other sites. Cold application was painful in control and AO subjects, but duration of pain sensation was significantly longer in AO patients (P = .019 in contralateral side; P = .029 in affected side).
Conclusions: The finding of extended painful aftersensation following cold application in AO patients supports the involvement of central mechanisms. The cold test is clinically easy to apply and of clinically significant value.
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