A study of the temporomandibular joint during bruxism

A finite element model of the temporomandibular joint (TMJ) and the human mandible was fabricated to study the effect of abnormal loading, such as awake and asleep bruxism, on the articular disc. A quasilinear viscoelastic model was used to simulate the behaviour of the disc. The viscoelastic nature of this tissue is shown to be an important factor when sustained (awake bruxism) or cyclic loading (sleep bruxism) is simulated. From the comparison of the two types of bruxism, it was seen that sustained clenching is the most detrimental activity for the TMJ disc, producing an overload that could lead to severe damage of this tissue. Extreme overload stress on cartilage during clenching can lead to significant damage to the jaw joint, researchers in Spain report. Around 85% of people suffer from awake or sleep bruxism —clenching / grinding of the jaw — at some point in their lives. Bruxism can lead to chronic pain and in extreme cases may do irreparable damage to the temporomandibular joint (TMJ). Maria Commisso and colleagues at the University of Seville built a finite element computer model of the TMJ and human mandible to examine the effect of abnormal loading stresses on the TMJ articular disc. The researchers modelled the behavior of the disc under sustained and cyclic loading, as found in awake and sleep bruxism, respectively. They found that sustained clenching in awake bruxism is the most damaging to disc cartilage.