A device (1) for the mandibular advancement, a process for making an appliance (10) for the mandibular advancement and the appliance realized； the device comprises a first engagement element (2) associable with the lower dental arch or mandible and a second engagement element (3) associable with the upper dental arch or maxilla, said engagement elements (2, 3) being provided with a first inclined engagement surface (21) and a second inclined engagement surface (31) for determining said mandibular advancement； the first engagement element (2) comprises a core (22) covered by a covering body (23) provided with a pocket adapted to the housing of said core (22), the second engagement element (3) comprising an orthodontic screw (33) adapted to determine the displacement of the second inclined plane (31), the core (22) having an inclined portion (221 B) destined to define, in cooperation with the respective covering, said first inclined engagement surface (21).
