FIELD: medicine.SUBSTANCE: invention refers to medicine, namely to dental instruments, and can be used for elongation of denture of lower jaw and free space for eruption of permanent teeth with its deficiency. Disclosed is a device, characterized by that on crowns of premolars from their outer side, and on molars – on the tongue side there are rigidly fixed beams Ø 0.9 mm with freely movable springs Ø 1.1 mm, on the ends of which there are detachable movable limiters Ø 1.0 mm for adjustment of spring compression with increasing distance between molars and premolars, and on molars and premolars opposite sides on the beams there are tubes with inner Ø 1.0 mm for inserting springs on the beams, wherein one of them is introduced into the elastic tube – insulation, at that, from the lingual side of the teeth necks there is an elastic arc of steel Ø 1.2 mm, coated with bioinert material, the ends of which are rigidly fixed to crown crowns of premolars. Device, by double-sided springs in relation to displaced tooth, creates pressure from the outer and inner sides of the tooth for controlled tooth movement along the guide beams, which prevents one-sided inclination or turning of the molar and reduces complications when moving the tooth, higher effectiveness of orthodontic treatment. Cast crowns are modeled individually by tooth shape with account of interdental contacts； therefore, teeth separation is not required when fixing the device. This makes it easy to fit in the oral cavity, provides 100 % adhesion to the tooth surface, which reduces the number of decementings and reduces the patient's discomfort. This simplifies structure as a whole, reduces labor intensity of doctor and mechanic. Device does not require cooperation of medical staff with a patient, since it is activated by an orthodontist once every two weeks. It does not require activation for the first two weeks of treatment, as length of springs is more than distance between crowns of teeth by 5 mm. Thus, from t
