The comparison between pains, difficulties in function, and associating factors of patients in subtypes of temporomandibular disorders.

The aim of this study was to compare the multidimensional properties among subtypes of painful temporomandibular disorders (TMD): myofascial pain (group I), disc displacement (group II), arthralgia (group IIIa) and osteoarthritis (group IIIb). A total of 511 patients answered a battery of questionnaires, which included questions relating to intensity and duration of pain, the Japanese version of the McGill Pain Questionnaire, limitation of daily functions, the Hospital Anxiety and Depression Scale, the Eysenck Personality Questionnaire short-form and 34 items of behavioural contributing factors. Group IIIb showed significantly the highest age in all subtypes. Those in group I had higher depression scores than those in group II (P = 0.005). Group IIIa had a lower women's ratio than in group II (P = 0.001) and the patients showed a shorter pain duration than those in groups I (P = 0.000) and II (P = 0.001). Group IIIa patients also showed lower visual analogue scale (VAS) ratings for pain descriptors 'heavy' (P = 0.002) and 'tiring' (P = 0.004) than those of group I, and 'dull' (P = 0.005), 'heavy' (P = 0.001) and 'tiring' (P = 0.005) than those of group II. Group IIIa showed lower ratios of contributing factors of 'an awareness of grinding/clenching during sleep' (P = 0.000) and 'an awareness of clenching sensation when waking up at night' (P = 0.002) than those of group I, and also showed a higher ratio of 'a liking for a hard food' (P = 0.000) and lower ratio of 'talking for a long time on the telephone' (P = 0.001) than those of group II. In conclusion, although several properties were different between subtypes, the majority of them were similar in the four subtypes of TMD.