Development and validation of classification criteria for idiopathic orofacial pain for use in population-based studies

Aim: To develop and validate a questionnaire-based tool which would enable classification of idiopathic orofacial pain in the general population. Methods: A postal questionnaire-based cross-sectional survey was made of 4,200 randomly selected adults who were registered with a general medical practice in North West England. The questionnaire collected information on a number of factors: demographics (age, gender), orofacial pain (duration, descriptors, site, pattern, intensity, disability, and consultation behavior), and comorbidities (reporting of other unexplained symptoms and psychosocial factors). Subjects reporting orofacial pain were interviewed by an examiner blinded to their exposure status and classified into 1 of 3 categories: (a) dentoalveolar, (b) musculoligamentouslsoft tissue, and (c) idiopathic orofacial pain. Results: A high adjusted response rate of 72% was achieved (crude response rate 60%). Of those who reported orofacial pain and were eligible for interview (n = 218), 197 (88%) were interviewed. Subjects classified by interview into the idiopathic category were more likely to report aching, nagging, and chronic pain pain at multiple sites. They were also more likely to report facial trauma and other chronic symptoms and to have consulted multiple health-care workers. Variables that most strongly predicted membership into the idiopathic category were female gender, nagging, aching pain which was worse when stressed, and topography (pain at multiple sites and unilateral pain). Conclusion: The classification criteria developed for idiopathic orofacial pain can be used as a screening tool for subjects with this condition in the general population.