Psychometrics in temporomandibular disorders. An overview

The purpose of this paper is to review the methods and results of psychometric testings in temporomandibular disorders (TMD) during the past decade. Assessments of psychologic and behavioral factors have been performed for various reasons. The results are often ambiguous and comparisons troublesome. No encompassing psychologic TMD profile has been identified, but small elevations in anxiety, depression, somatization, and stress are often reported; they may be cause or effect. Subcategorization of the patients into diagnostic subgroups suggests that psychologic differences exist but may be small; myogenic patients may have more psychologic difficulties than 'joint' patients. More distinct, robust psychologic subsets of patients, unrelated to the structural diagnosis, have been identified by means of clustering techniques. Irrespective of clinical signs, a certain proportion of the patients are psychologically distressed, whereas others easily adapt to the pain and dysfunction. No single variable has been identified that can predict outcome or compliance. Several psychometric instruments are described.