Teeth grinding at night can damage the temporomandibular joints

In dentistry, whether sleep bruxism or nighttime bruxism is related to the development or progression of temporomandibular joint disease is controversial. A study conducted at the Medical University of Vienna found that some tooth shapes and locations can lead to problems with the temporomandibular joint due to bruxism. The results of the Benedikt Sagl team’s research were recently published in Advanced Research Journal†

About 15 percent of the population grinds their teeth while sleeping. The problem is especially common in young people. The massive pressure that is placed on the surfaces of the teeth and on the jaws is said to cause various dental problems and can also lead to jaw muscles and headaches. Researchers in Vienna have now investigated whether bruxism during sleep can negatively affect the structures of the temporomandibular joint (TMJ). Their research was based on the theory that specific combinations of tooth shape and tooth location during grinding influence the mechanical load on the TMJ and thus could be considered a risk factor for TMJ disease.

The flatter the tooth, the greater the load

The studies were conducted using an advanced computer model of the jaw region that includes bone, cartilage, and muscle structures. These computer models can be used to investigate research questions when direct patient studies are not feasible for ethical reasons. The subject of the study is the interaction of two simultaneous factors in the phenomenon of bruxism. The first is the shape of the affected tooth, more specifically the angle of inclination of the cusp that comes into contact with the electrode opposite it during grinding. The second is the site of contact with the tooth (the so-called wear face) during the dynamic grinding movement. The study simulated the effects of lateral grinding on the first molar and on canine teeth with six different directions of wear, resulting in a total of twelve simulated scenarios.

Sagel explains: “Our results show that both the angle of inclination and the location of the wear sides have an effect on the strength of the mechanical load on the temporomandibular joint. However, the deciding factor appears to be the steepness of the grinding aspect. The flatter the tooth, the greater the load on the joint, and therefore the greater the risk of developing TMJ.

Conversely, if the molars involved in bruxism had a steeper angle of inclination, then the calculated joint load was lower, even with the same “grinding force”. More research will now be conducted, along with clinical trials, to determine whether this finding can be incorporated into the development of therapeutic interventions for overnight grinding of teeth.