Epidemiology of chronic oro-facial pain

Introduction:The aetiology of unexplained chronic oro-facial pain is still unclear and treatment of patients with this condition tends to be influenced by the background of the clinician assessing them. The complex neural anatomy of the oro-facial region makes diagnosis and classification of chronic oro-facial pain conditions very difficult with substantial delays in arriving at the correct diagnosis. Patients are subjected to multiple tests and treatments which often do not improve symptoms and result in overuse of already stretched health care resources. In addition, although chronic oro-facial pain is a well-recognised entity in a clinical setting, its prevalence and impact in the general population is poorly understood. Previous epidemiological studies have investigated oro-facial pain in its entirety and therefore included a wide spectrum of cases ranging from trivial short-lasting pains like tooth sensitivity to the more severe intractable cases of chronic oro-facial pain. Factors associated with specific chronic oro-facial pain symptoms such as temporomandibular pain dysfunction are predominantly psychosocial. This coupled with higher prevalence in females and altered health seeking behaviour suggest that chronic oro-facial pain may share common characteristics with other frequently unexplained chronic symptoms such as irritable bowel syndrome, chronic fatigue and chronic widespread pain. Evidence from studies in clinic settings suggests that these chronic symptoms may co-occur. However, these studies have been limited by methodological shortcomings like selection and misclassification bias.Aims:The principal aims of the present study were to determine: (a) whether chronic oro-facial pain co-occurs with other frequently unexplained symptoms (b) whether factors associated with chronic oro-facial pain are common across symptoms.MethodsA population-based cross-sectional study was conducted using 4200 randomly selected adults who were recruited from the age-sex register of a General Medical Practice in North West, England. The study examined the prevalence and co-occurrence of chronic oro-facial pain with three other chronic symptoms that are frequently unexplained: chronic widespread pain, Irritable bowel syndrome and chronic fatigue. Validated instruments were used to measure the occurrence of symptoms and to collect information on a variety of associated factors: demographic (age, gender), psychosocial (anxiety, depression, illness behaviour, life stressors and reporting of somatic symptoms) and mechanical (teeth grinding, facial trauma, missing teeth and reporting that the teeth did not fit together properly). Subjects reporting oro-facial pain and who consented to further contact were clinically examined by an interviewer who was blinded to the subjects’ questionnaire responses. Oro-facial pain was then classified, using clinical examination, into four broad categories: musculoligamentous and soft tissue, neuralgic/vascular, dentoalveolar and unexplained.Results2505 subjects returned completed questionnaires (adjusted response rate 72%). The prevalence of Chronic Widespread Pain was 15%, Chronic Oro-facial Pain 7%, Irritable Bowel Syndrome 9% and Chronic Fatigue 8%. The study found that 587 subjects (27%) reported one or more symptoms: 404 (18%) reported one symptom, 134 (6%) reported two, 34 (2%) reported three, whilst 15 (1%) reported all four symptoms. The occurrence of multiple symptoms was much greater than would be expected by chance (p