Medical apparatus and instruments; stents; stents that can be inserted into nasal cavities; nasal dilators; orthoses; nasal orthoses; mandibular orthoses; prostheses; apparatus, instruments and devices made of reinforced plastic fibers, for medical use; apparatus, instruments and devices made of reinforced plastic fibers, for medical use, for improving breathing; medical devices implanted in the respiratory tract and oral cavity; medical devices made of reinforced plastic fibers implanted in the respiratory tract and oral cavity; medical apparatus and devices to be placed on or in the nose