An orthodontic device (10) comprising at least one first bearing means (17-19) for bearing on the left-hand side of an upper jaw of a patient to be treated, at least one second bearing means (20-22) for bearing on the right-hand side of said jaw and a central actuator (23, 51) for modulating a distance between said hearing means in order to expand the palate of said patient, characterised in that the device (10) further comprises a mechanical rotary link (R1, R2) between the actuator and said first bearing means and a mechanical rotary link (R1, R2) between the actuator and said second hearing means in order to allow geometric adjustment while the device (10) is being fitted in the mouth of the patient, at least in the vertical direction, the anterior-posterior direction or the transverse direction.
