Pain Duration and Intensity Are Related to Coexisting Pain and Comorbidities Present in Temporomandibular Disorder Pain Patients

Aims: To investigate the relationships between three pain parameters (duration, intensity, and frequency), the number of pain sites and comorbidities, and the risk of having coexisting pain and/or comorbidities in patients with temporomandibular disorder (TMD) pain. Methods: The sample consisted of 198 outpatients attending the Dental Hospital of Chulalongkorn University. TMD pain was determined using the Diagnostic Criteria for TMD. Pain lasting 3 months or longer was defined as chronic pain. Pain intensity was reflected using a 0- to 10-point numeric rating scale, and pain frequency was assessed with the percentage of pain days over a 2-week period. The number of pain sites was evaluated using the Widespread Pain Index. The presence of comorbidities was assessed with a validated diagnostic questionnaire. The associations were analyzed using Spearman rho test, multiple linear regression, and logistic regression, with a significance level of P <= .05. Age and gender were analyzed as confounders. Results: The number of pain sites was related to pain duration, pain intensity, and age. The number of comorbidities was associated with pain duration. Neither pain frequency nor gender were related to the number of pain sites or comorbidities. When the pain duration reached 1 month, patients had a 1.045-times higher probability of pain beyond the orofacial area (odds ratio [OR] = 1.045; 95% confidence interval [CI] = 1.024 to 1.066; P = .001) and a 1.028-times higher probability of comorbidities (OR = 1.028; 95% CI = 1.005 to 1.05; P = .008). For an increase of 1 score on the numeric rating scale, patients had a 1.206-times higher probability of pain presence beyond the orofacial area (OR = 1.206; 95% CI = 1.068 to 1.344; P = .026). Conclusion: High pain intensity and long pain duration increase the probability of having coexisting pain and comorbidities in TMD pain patients.