Adhesive force: the underlying cause of the disc anchorage to the fossa and/or eminence in the temporomandibular joint--a new concept.

The commonly held cause for using the closed lock technique is the prevention of disc sliding by using the non-reducible disc. The purpose of this study was to re-evaluate the pathogenesis of sudden and persistent severely limited mouth opening associated with a total lack of disc sliding in view of the fact that it is promptly released by lavage of the upper compartment of the temporomandibular joint (TMJ). The proposed pathogenesis is based upon earlier clinical and laboratory findings of the first author coupled with pertinent information culled from the literature. It is suggested that sliding of the disc in the TMJ is enabled due to the presence of phospholipids protected by hyaluronic acid (HA) that constitute an efficient lubrication system. Joint overloading may be associated with uncontrolled production of reactive oxygen species (ROS) that causes degradation of the HA, followed by the exposure of the phospholipids to lysis by phospholipase A2 (PLA2). The denuded, smooth and elastic articular surfaces that possess high surface energy become strongly adherent when placed in direct physical contact with each other. The presence of an extremely thin film of fluid (sub-boundary lubrication) between the mating surfaces may cause even higher adhesion. These adhesive forces are probably responsible for the flexible disc anchorage to the fossa and/or eminence. They also explain the immediate release of the disc and rehabilitation of its sliding following arthrocentesis. Since it is uncommon for two opposing surfaces to be stripped bare and to become adherent, the likelihood of anchored disc phenomenon (ADP) occurring and recurring is very low.