Mandibular advancement device

1. A mandibular advancement device comprising:

an upper tray assembly comprising a rigid upper chassis and a maxillary tray; and

a lower tray assembly comprising a rigid lower chassis and a mandibular tray;

wherein the rigid upper and rigid lower chassis define an interlocking arrangement configured to releasably lock the upper and lower tray assemblies into a selected one of a plurality of predefined positions, each of the predefined positions defining a different offset between the upper and lower tray assemblies to enable adjustment of a degree of mandibular advancement relative to a posterior-anterior axis when used; and

wherein the interlocking arrangement includes locking channels and guide members on respective sides of an anterior portion of the mandibular advancement device, the locking channels and guide members each formed by the rigid lower chassis and the rigid upper chassis, respectively, the locking channels each extending along a length parallel to the posterior-anterior axis of the mandibular advancement device, the locking channels each being uniform in cross section normal to the posterior- anterior axis along the length, and the locking channels each including a laterally extending retaining flange, and the guide members of the rigid upper chassis configured to be received in the locking channels and retained by the laterally extending retaining flanges of the rigid lower chassis to prevent separation of the rigid upper and rigid lower chassis in a vertical direction, wherein the locking channels and guide members each extend from a labial edge to a lingual edge of the rigid lower chassis and the rigid upper chassis, respectively, and

wherein the interlocking arrangement further includes a locking member and an at least partly corresponding locking recess or aperture in each posterior end of the mandibular advancement device to prevent relative movement in a transverse direction, wherein the locking members and the at least partly corresponding locking recesses or apertures are entirely posterior to the locking channels and guide members.

2. The mandibular advancement device of claim 1 , wherein the different offsets define different levels of anterior protrusion of the mandibular tray relative to the maxillary tray.

3. The mandibular advancement device of claim 1 , wherein at least 3 different offsets are provided by the plurality of predefined positions, and wherein the at least 3 different offsets include offsets between 0 mm and 10 mm.

4. The mandibular advancement device of claim 1 , wherein the different offsets are provided at increments of 1 mm.

5. The mandibular advancement device of claim 1 , wherein the mandibular advancement device includes indicia to identify a chosen offset.

6. The mandibular advancement device of claim 1 , wherein each locking member is uniform in cross section, wherein each locking member extends outwardly from one of the upperand lower chassis, and each at least partly corresponding locking recess or aperture is defined in an opposite side of the rigid upper and rigid lower chassis.

7. The mandibular advancement device of claim 1 , wherein each locking member is keyed to at least part of each at least partly corresponding locking recess or aperture.

8. The mandibular advancement device of claim 1 , wherein each at least partly corresponding locking recess or aperture comprises an elongate locking channel, wherein each locking member is configured to be received in one of a plurality of predefined positions in the corresponding elongate locking channel.

9. The mandibular advancement device of claim 1 , wherein each locking member includes a pattern along its edges corresponding to a portion of a repeating locking pattern.

10. The mandibular advancement device of claim 1 , wherein the guide members and the locking channels engage with each other in a dovetail arrangement.

11. The mandibular advancement device of claim 1 , wherein an opening is defined in the anterior portion of the mandibular advancement device to enable airflow therethrough when used.

12. The mandibular advancement device of claim 1 , wherein the mandibular advancement device is U-shaped in plan view and is symmetrical around a sagittal plane.

13. The mandibular advancement device of claim 1 , wherein the maxillary tray is formed of another material than the rigid upper chassis, wherein the maxillary tray is softer than the rigid upper chassis, and wherein the maxillary tray is overmoulded over the rigid upper chassis.

14. The mandibular advancement device of claim 1 , wherein each of the rigid upper and rigid lower chassis is unitarily formed and each of the maxillary tray and mandibular tray is unitarily formed.

15. The mandibular advancement device of claim 1 , wherein the maxillary tray and the mandibular tray are formed of a thermoplastic, enabling the maxillary and mandibular trays to be heated to be configured to form to a user's teeth and gums.