Objective: To study if visco-supplementation therapy is useful to the internal derangement (ID) of temporomandibular joint (TMJ).
Methods: Sixty-three ID cases (69 TMJs) were studied by visco-supplementation therapy. The upper and/or lower articular cavities were irrigated with 5 ml normal saline and injected 0.3-1.0 ml 1% hyaluronate (HA) into articular cavity. If the symptoms of the disease still existed one week later, the therapy should be repeated for 1-2 times, once a week. The control group cases were injected 1 ml 2% lidocaine instead of HA. 8 other TMJs of 6 ID cases and 2 normal cadavers were studied with scanning electron microscopy (SEM) and light microscopy (LM).
Results: The visco-supplement therapy was useful to ID patients. The difference between the test group and control group had statistical significance (chi 2 = 6.6535, P < 0.01). SEM and LM showed that the condyle, disc and bilaminar region in ID were degenerated or destroyed.
Conclusions: The friction between the articular surfaces in ID was increased and the bilaminar region could not retract the disc as in healthy TMJ. The visco-supplementation therapy can decrease the friction and resume the normal rheology of the diseased TMJs.