Clinical applications of drill free screws in maxillofacial surgery.

Drill free screws are newly designed osteosynthesis screws with specially formed tips and cutting flutes, which act like a cork-screw and can be inserted into bone without predrilling. A prospective study on 82 patients was performed in order to investigate the efficiency of mini- and micro-drill free screws (DFS) in clinical use and to find out areas in maxillofacial traumatology and orthognathic surgery, where the application of this new type of screw may be recommended. Thirty-eight Le-Fort-osteotomies, 23 central and lateral midfacial fractures and 21 fractures of the mandible were fixed using the Champy titanium micro/miniplate system and in total 518 center-drive titanium micro-DFS (1.5 mm) and 392 center-drive titanium mini-DFS (2 mm) with lengths between 4 and 7 mm. The results showed that the grip of micro- and mini-DFS was sufficient for the fixation of bone fragments in the central and lateral midface and in the mandibular area. The insertion of DFS was simple and is recommended in the area of the central midface; the insertion of the screws was difficult, but possible in the anterior mandible and in the lateral midface. The application of DFS in the mandibular angle region is not recommended.