Evaluation of the Mandibular Function Impairment Questionnaire in Clinical Diagnosis of Temporomandibular Joint Disorder.

Introduction: The Mandibular Function Impairment Questionnaire (MFIQ) was developed for clinical assessment of functional impairment in patients with temporomandibular disorder (TMD). It allows patients to rank difficulty performing 17 jaw-related functions as low, moderate or severe. Our study was designed to determine whether the MFIQ is also helpful in differentiating TMD from other causes of orofacial pain in a clinical setting.

Methods: A retrospective study was conducted at a private oral medicine/orofacial pain clinic. New patients who attended with orofacial pain complaints were selected (n = 174). All patients had filled out the MFIQ as part of new patient intake forms.

Results: The study population consisted of 120 TMD patients, 25 patients with burning mouth syndrome (BMS), 19 with oral lesions (OLs) and 10 with trigeminal neuralgia (TN). TMD patients had significantly greater difficulty taking a large bite, yawning, chewing hard and resistant foods including meat, raw carrot, and apples compared with OL and BMS patients. The MFIQ alone was not able to distinguish between TMD and TN.

Conclusions: The MFIQ is a short questionnaire that is openly accessible and can be completed relatively quickly by patients in a general dentistry clinic. High ranking of difficulty for items associated with taking a large bite, chewing hard or resistant food and yawning in the presence of complaint of orofacial pain should raise suspicion of TMD and TN as a possible source of the pain.