The functional impact of extraction and nonextraction treatments: a long-term comparison in patients with "borderline," equally susceptible Class II malocclusions.

Discriminant analysis was used to identify in retrospect a sample of 63 patients who had presented initially with Class II malocclusions that, according to then prevailing standards of specialty practice, could have been treated either with or without the extraction of premolars. These "borderline" subjects (33 extraction, 30 nonextraction) were then recalled for a long-term evaluation (on average, about 14 years after treatment) of the functional status of both the head and the neck musculature and the temporomandibular joints. In terms of a menu of 62 signs and symptoms (muscle palpation, joint function) that are commonly thought to be characteristic of craniomandibular disorders, there were no significant differences between the extraction and nonextraction samples. The present data therefore fail to support the popular notion that "premolar extraction causes 'TMJ'".