Researchers warn of jaw training device

U.K. researchers are warning the dental community about a "face and neck toning" device called Jawzrsize, cautioning that it may produce negative effects, in a letter published on February 26 in the British Dental Journal.

The device is a rubber ball with or without upper and lower occlusal rests for the incisors, according to authors T. Nagpal and A. Gupta. The user bites up and down on the device in repetitions or sets throughout the day. The device's resistance ranges from 20 lb to 40 lb.

The researchers objected to numerous claims on the device's website, including that Jawzrsize can provide improved jaw function and relief for temporomandibular joint disorder (TMJD).

"It seems likely that the repeated use of this device will result in far more stresses on the TMJ and cause significant wear on the articular disc potentially triggering various TMJD symptoms from crepitus to complete dislocation," they wrote.

The authors further compared the stress of Jawzrsize to that experienced by bruxers, warning that people who use the device may require interventions to reduce activity of the masseter muscle. They recommended a less stressful jaw conditioning technique.

"Following a routine of simple resistance exercises with your own hands is regarded as a useful tool in conservative management of TMJD," they wrote.