The invention relates to a two-part mandibular protrusion splint (1) for preventing snoring and/or obstructive sleep apnoea, comprising a lower part (2) and an upper part (3), comprising shaping and flexurally rigid trays (2a, 3a) which are open towards the mandibula and maxilla respectively, where the bottom surfaces of the outsides of the two trays (2a, 3a) are connected to one another in such a way that they are continuously adjustable relative to one another in the longitudinal direction, and a corresponding ready-to-use set for the production or restoration of mandibular protrusion splints consisting of (i) shaping and flexurally rigid trays (2a, 3a) with preformed attachment elements on the outsides of each of the bottom surfaces; (ii) one or more adjustment screws (10) for connecting the attachment elements; and (iii) optionally use instructions.