Assessing the effectiveness of Hospital-Based Manufactured Medical Device Restorabite for treatment of Trismus in adults after head and neck cancer surgery

The use of Restorabite will be offered to participants for the treatment of trismus after head and neck cancer surgery in place of other standard of care devices such as Ark-J (stacked wooden tongue depressor) or TheraBite. Restorabite is a mass produced and non-custom made device, however, participants will be assigned to a specific insert by treating speech pathologist and surgeon depending on the severity of trismus and the recovery from the surgery. Participants will be asked to be involved with following interventions. • Passive jaw range of motion exercises using Restorabite • Active jaw range of motion exercises using Restorabite • 10 x 1hr weekly sessions face to face at speech pathology clinic at hospital or over telehealth with speech pathology with minimum 3 years' experience. Gradual progression through the force hierarchy as clinically indicated. • Home practice: daily for 20 minutes for duration of study (10 weeks). • Measurement of Interincisal distance at baseline, at the end of 10 x weekly sessions, 6 months and 12 months follow up appointment Passive and active jaw range of motion exercises is a continuous exercise performed with Restorabite. It involves inserting the pressed down Restorabite between the front teeth and letting the device stretch the jaw (passive motion exercise) then bite down on the mouth guards (active motion exercise). Then repeat the letting go of the bite (passive motion exercise) and biting down on the device (active motion exercise). During the 1 hour weekly session, speech pathologist will determine how many repetitions should be carried out and recommend the duration of each exercise (ie Hold the passive action for 1 minute then hold the active action for 1 minute. Repeat 10 times). Participants will be asked to carry out a personalised exercise regime as home practice every day. During the 1 hour weekly session, speech pathologist will determine the passive and active motion exercise regime for coming week. Interincisal distance will be measured at the start of the session then participants will be asked to carry out the prescribed exercise regime. Interincisal distance will be measured at the end of the session to observe a change in interincisal distance. To monitor adherence to the intervention speech pathologists will closely follow up participants. To increase the adherence to the intervention, speech pathologists will set up a 10 week appointment plan at the beginning of the trial and also offer tele-health appointments.