Examples of some custom-made mandibular repositioning appliances (MRAs) used in clinical practice: a) a home-made monobloc appliance; b) the Butterfly MRA (Respident, Antwerp, Belgium), a duobloc MRA with attachments for adjustment of mandibular protrusion ... Examples of some custom-made mandibular repositioning appliances (MRAs) used in clinical practice: a) a home-made monobloc appliance; b) the Butterfly MRA (Respident, Antwerp, Belgium), a duobloc MRA with attachments for adjustment of mandibular protrusion in the frontal teeth area; c) the Thornton Adjustable Positioner (TAP) appliance (Airway Management, Inc., Texas, USA), composed of both mandibular and maxillary arches with a screw mechanism in the upper arch to allow for the advancement of the mandible; and d) a custom-made two-piece MRA with two lateral screw devices that permit incremental protrusion of the mandible (SomnoDent MAS; SomnoMed Ltd, New South Wales, Australia). O.M. Vanderveken, and A. Hoekema breathe 2010;7:157-167 ©2010 by European Respiratory Society