Classification of chronic orofacial pain: applicability of chronic headache criteria

The aim of this study was to test the temporal definitions of chronic daily headache (CDH) in an orofacial pain population and examine the features of the so-defined chronic orofacial pain (COFP).

Patients with orofacial pain presenting for >3 months were prospectively collected for 2 years. Temporal patterns were applied based on the headache literature, and patients were subdivided into: COFP: ≥15 days monthly, lasting >4 hours (long-lasting CDH); daily orofacial pain (DOFP): ≥15 days monthly, but mean attack duration ≤4 hours (short-lasting CDH); and episodic orofacial pain (EOFP): <15 days monthly (episodic headaches).

A total of 328 patients were examined. The temporal criteria defined 149 patients as COFP, 116 as DOFP, and 41 as EOFP. COFP was not distinctive in the parameters used in the diagnostic process (laterality, severity, muscle tenderness, waking) or demographic features. These were, however, significantly associated with specific diagnosis.

This study provides a base for the clear definition of COFP that has the distinctive advantage of being identical to that used in headache. Additionally, our results clearly show that COFP should be regarded as a temporal definition and not a diagnosis.