Drill Free Screws: a new form of osteosynthesis screw.
Although the application of self-tapping and non self-tapping screws is virtually universal in cranio-maxillofacial 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%.
Heidemann
W
W
Department of Maxillofacial Surgery, Otto-von-Guericke University, Magdeburg, Germany.
Gerlach
K L
KL
Gröbel
K H
KH
Köllner
H G
HG
D000818:Animals; D001863:Bone Screws / Q000009:adverse effects; D004867:Equipment Design; D004868:Equipment Failure; D005593:Fracture Fixation, Internal / Q000295:instrumentation*; D006358:Hot Temperature / Q000009:adverse effects; D007431:Intraoperative Complications; D008334:Mandible / Q000601:surgery; D008422:Materials Testing; D010027:Osteotomy / Q000009:adverse effects / Q000295:instrumentation; D011143:Polyvinyl Chloride; D013314:Stress, Mechanical; D013499:Surface Properties; D013552:Swine; D014025:Titanium; D019415:Torque; D014934:Wood
D011143:Polyvinyl Chloride; D014025:Titanium