A special tube is disclosed for the insertion of materials inside the maxillary sinus in order to displace the Schneiderian membrane. The tube is connected to a source of a flowable material. The tube is inserted through the alveolar ridge beneath the maxillary sinus and when the flowable material is advanced through the tube the Schneiderian membrane is lifted. The tube can be part of a dental implant which is screwed inside the alveolar ridge.