A method of treating sleep disorder breathing in a patient, the method comprising in a first step providing a set of oral appliances comprising a first and at least a second oral appliance. Each of the first and at least second oral appliances comprises a generally U shaped appliance body including an inner wall, an outer wall, and a web interconnecting the inner wall and the outer wall. The web has a front section and two arms with trailing ends. The web comprises at least one breathing hole so as to define a total cross sectional area for breathing and the total cross sectional area for breathing of the first oral appliance is larger than the total cross sectional area for breathing of the second oral appliance. In a second step, a patient wears the first oral appliance in a first treatment stage whilst sleeping for a first period of time and in a third step the patient wears the second oral appliance in a second treatment stage whilst sleeping for a second period of time.