The invention relates to a regulatable intraoral mandibular advancement device that can be used to prevent snoring and sleep apnoea. Said device comprises two splints connected by a central screw (1) inserted into a sheath (2) comprising an upper ring (3), said sheath being used as a guiding housing (4) for an upper bar (5) of an upper plate (6), and the lower part of the sheath comprising a longitudinal groove (8) enabling the course of an inner mobile threaded (10) ring (9) that is displaced by the screw (1), and on which a lower displacement ring (11) is arranged, open or closed, said ring being provided with a perpendicular hole (12) with elipsoidal conicity, in which the lower bar (13) fixed to the lower maxillary plate (14) is inserted. Said screw (1) is locked to the sheath (2) on its rear part.
