Drill Free Screws: a new form of osteosynthesis screw

• Published in: Journal of cranio-maxillo-facial surgery Vol. 26; no. 3; pp. 163 - 168
• Main Authors: Heidemann, Wolfgang, Gerlach, Klaus Louis, Gröbel, Karl-Heinz, Köllner, Hans-Georg
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.06.1998; Elsevier
• Subjects: Animals; Biological and medical sciences; Bone Screws - adverse effects; Dentistry; Equipment Design; Equipment Failure; Fracture Fixation, Internal - instrumentation; Hot Temperature - adverse effects; Intraoperative Complications; Mandible - surgery; Materials Testing; Medical sciences; Osteotomy - adverse effects; Osteotomy - instrumentation; Polyvinyl Chloride; Stress, Mechanical; Surface Properties; Surgery (general aspects). Transplantations, organ and tissue grafts. Graft diseases; Swine; Technology. Biomaterials. Equipments; Titanium; Torque; Wood; Human; Maxillofacial; Osteosynthesis; Torque measurement; Result; Pull out test; Type; Treatment; Equipment; Screw; Surgery; Technique; Comparative study; Bibliographic review
• ISSN: 1010-5182; 1878-4119
• DOI: 10.1016/S1010-5182(98)80007-3

Although the application of self-tapping and non self-tapping screws is virtually universal in craniomaxillofacial surgery, the inevitable, time consuming procedure of drilling a pilot hole has some potential disadvantages, such as damage to nerves, tooth roots or tooth germs, thermal necrosis of the bone and drill bit breakage. Drill Free Screws (DFS) are a recently developed type of osteosynthesis screws, having a tip like a cork screw and specially formed cutting flutes which enable insertion of the screws without drilling. DFS 1.5 and 2 mm were inserted into discs of wood, polyvinylchloride (PVC) and porcine mandibular bone of varying thicknesses between 2 and 4 mm. The values of insertion torque and maximum torque were recorded using an electric torque tester. Thereafter, the screws were inserted with a fixed torque and uniaxial pull out tests were performed. In comparison with this, the same procedure was performed using 1.5 and 2 mm self-tapping titanium screws. Ten trials for each screw-material-combination were conducted to determine insertion torque, maximum torque and pull out analysis. The results showed that the holding power of DFS lay between 70 and 104% of the holding power of self-tapping titanium screws; only in PVC was the difference more than 15%.