Mandibular Advancement Splint (MAS)

What is it?

A mandibular advancement splint is a small device used for the treatment of snoring and obstructive sleep apnoea. It is the main alternative to CPAP therapy. It is worn inside the mouth clipped onto the patient’s teeth during sleep.

How does it work?

It is thought to work by pushing the lower jaw forward, relative to the top jaw and tensioning the back of the tongue, slightly increasing the upper airway dimensions.

How is it fitted?

The device needs to be fashioned by a specialist dentist. Good dental hygiene is required and the patient needs to have at least some upper and lower native teeth. A cast is initially taken of the patient’s teeth. This is sent away to a lab which makes the device. Over the next few weeks, the device is progressively altered to increasingly push the lower jaw forward.

Significant advantages over CPAP

  • No external power source is required.
  • The device is inconspicuous when worn.

Significant problems with the device

It is not always effective. It works extremely well in about a third of patients, partially in a third and not at all in the remainder. While some interesting research is being carried out to predict the response to this device, currently it is not possible to predict whether the device will work in an individual. Consequently, close follow up and a further sleep study is required post fitting. Minor facial skeletal and dental changes may occur after several years of use therefore long term follow up by the fitting dentist is also recommended.