Splints as therapeutic treatment instruments in temporomandibular disorder patients are widely accepted. The combination of splint therapy and aligner orthodontics not only provides comfortable and almost invisible treatment but also constitutes a powerful instrument for the orthodontic treatment of the temporomandibular disorder patient. To this end, precise knowledge of the temporomandibular joint, temporomandibular disorders and treatment using removable and fixed splints is indispensable. The two-phase treatment and the combination of fixed splint and aligner transform occlusal splint therapy into a permanently stable occlusion with physiological posterior vertical support. Keywords: aligner, temporomandibular disorder (TMD), temporomandibular joint (TMJ)