Orthodontic apparatus (1) for housing in the mouth of a user, comprising: - a mounting arrangement (3) for mounting in an upper arch of a user, in which the mounting arrangement comprises an outer wall (7) and an inner wall (9) and a soul (11) extending between the inner and outer walls, and in which the outer wall, the soul and the inner wall collectively define an upper channel (21) within which the teeth of the upper arch for mounting the apparatus in an upper arch of a user, and define a lower channel (23) within which the teeth of the lower arch can be accommodated, and the outer wall (7) has an outer buccal surface (31) , an upper channel surface (33) and a lower channel surface (35), and the inner wall (9) has a lingual inner surface (37), an upper channel surface (39) and a lower channel surface ( 41), and the soul (11) includes a supe channel soul surface rior (43) and a lower channel core surface (45), the outer wall has an upper outer wall portion (13) above the core (11) and a lower outer wall portion (15) below the core , and the inner wall (9) has an upper inner wall part (17) above the core (11) and a lower inner wall portion (19) below the core, each of the outer walls (7) e Inner (9) includes a region of incisors that extends through the region of incisors of the arc of a user and two regions of canines on both sides of the region of incisors to extend through the regions of canines of a user, and two molar regions on both sides to extend through the molar regions of a user, and the mounting arrangement, which includes each of the inner and outer walls, has a generally curved shape with a region of curved incisors and being the regions of canines and molars in the form of two arms that extend backwards from each end of the region of incisors in order to correspond generally to the shape of a user's arch, and the orthodontic apparatus being characterized in that the mounting arrangement (3) is flexible in an elastic manner, and the outer (7) and inne
