Factors associated with the temporomandibular disorder, pain dysfunction syndrome (PDS): Manchester case-control study.

OBJECTIVES: To determine the individual and combined effects of potential risk factors in relation to the temporomandibular disorder, Pain Dysfunction Syndrome (PDS).
DESIGN: Case-control study.
MATERIAL AND METHODS: Cases were new referrals to the temporomandibular disorder clinic of the University Dental Hospital of Manchester, diagnosed with PDS. Controls were randomly selected from 24 dental practices. Using a postal questionnaire information was collected on socio-demographic, local mechanical, psychological factors, co-morbidities and illness behaviour. The adjusted participation rate was similar in cases and controls (64%), and 131 cases and 196 controls finally participated in the study.
RESULTS: Compared with the controls, the cases were more likely to report that their teeth felt as though they did not fit together properly [odds ratio (OR) 8, 95% Confidence Interval (CI) 6-13] and report history of facial trauma (OR 3, 95% CI 2-6). Both diurnal and nocturnal grinding were significantly associated with PDS, and individuals who reported grinding their teeth both during the day and at night had a risk of 6; 95% CI 3-13 for PDS compared with those who did not. A history of orthodontic treatment, having any dentures, having missing teeth, use of chewing gum or biting the fingernails did not show any relationship with PDS. People who took medication for the bowels had a higher risk of PDS (OR 2, 95% CI 1-4). Participants with frequent headaches had a threefold increase in risk of having PDS (OR 3, 95% CI 2-5) while having pain in parts of the body other than the head was associated with an OR of 3 (95% CI 2-5). An increased propensity to have PDS was seen in those individuals with higher levels of psychological distress (OR 3; 95% CI 1-4 in the highest category, test for trend P < 0.001) and sleep disturbance (OR 5; 95% CI 2-94 in the highest category, test for trend P < 0.001). Aspects of illness behaviour, such as disease conviction (OR 4; 95% CI 2-9 in the highest category) and perception of illness (0.3; 95% CI 0.2-0.5) were associated with PDS. The result for the denial scale became statistically significant after adjustment for age and gender (2; 95% CI 1-3).
CONCLUSIONS: The current case-control study provides complementary epidemiological information on oro-facial pain (OFP) and supports a multifactorial aetiology of PDS, with factors from many domains, including local mechanical factors, psychological and co-morbidities. People with PDS were characterized by frequent headaches, history of facial trauma, teeth grinding, sleep problems, pain elsewhere in the body and high levels of psychological distress. From the results of current study and available evidence it seems inappropriate to consider PDS in isolation and future research should adopt a multidisciplinary approach to OFP.