EFFECTS OF MAJOR CLASS-II OCCLUSAL CORRECTIONS ON TEMPOROMANDIBULAR SIGNS AND SYMPTOMS

This study explored the relationship between malocclusion and signs an d symptoms of temporomandibular disorders (TMD) in 124 patients with s evere Class II malocclusion, before and 2 years after bilateral sagitt al split osteotomy (BSSO). Patients were evaluated with the Craniomand ibular Index (CMI), the Peer Assessment Rating Index (PAR Index, to as sess gross changes in the occlusion), and symptom questionnaires. The results showed a significant improvement in occlusion; PAR Index: scor es dropped from a mean of 18.1 before surgery to a mean of 6.1 at 2 ye ars postsurgery (P < 0.001). The CMI and masticatory index (MI) for mu scle pain indicated clinically small but statistically significant imp rovement (P 0.0001) from before surgery (mean CMI = 0.14, mean MI = 0. 15) to after surgery (mean CMI = 0.10, mean MI = 0.08). The number of patients with clicking upon opening decreased significantly from 3.3 ( 26.6%) to 13 (10.5%) (P = 0.001). However, the number of patients with fine crepitus increased from 5 (4.0%) before surgery to 16 (12.9%) at 2 years postsurgery (P = 0.005). Significant reductions in subjective pain and discomfort were also found 2 years after surgery. The magnit ude of change in muscular pain was not related to the severity of the pretreatment malocclusion, a finding that suggests that factors other than malocclusion may be responsible for the change in TMD.