Takenami Y, Kuboki T, Acero C O, Maekawa K, Yamashita A, Azuma Y
Department of Fixed Prosthodontics, Okayama University Dental School, Japan.
Dentomaxillofac Radiol. 1999 Jul;28(4):214-8. doi: 10.1038/sj/dmfr/4600443.
To determine the effect of sustained incisal clenching on the width of the temporomandibular joint space.
Nine normal subjects clenched on an anterior appliance for 10 min at 49 N. Sagittal tomograms were obtained during comfortable closure in the intercuspal position (ICP) (ICP-Before), comfortable closure on bite force transducer without clenching (BFT-Before), start of clenching (BFT-0), end of 5 min clenching (BFT-5), end of 10 min clenching (BFT-10), comfortable closure on the bite force transducer immediately after clenching (BFT-After) and comfortable closure in ICP after clenching (ICP-After). Joint space dimensions were automatically measured by a computerized image analysis system.
The minimum joint space dimension was significantly reduced at BFT-5 (P = 0.0381), BFT-10 (P = 0.0019) and BFT-After (P = 0.0053) in relation to BFT-Before. The condylar position was also significantly shifted upward at BFT-0 (P = 0.0422), BFT-5 (P = 0.0005), BFT-10 (P = 0.0001), and BFT-After (P = 0.0004) in relation to BFT-Before.
Sustained incisal clenching at 49 N causes significant anterior joint space reduction. We believe this is due to marked compression of the articular cartilage and disc.
