Does the Location of the Cutting Flute of Self-Tapping Screws in Bony Substrate Affect the Removal Torque?
Read full paper at： http://www.scirp.org/journal/PaperInformation.aspx?PaperID=53122#.VLXQ0snQrzE Author(s) David James Chapman Graham 1* , Alistair Spiers 1 , Eric Swarts 2 , Colin Whitewood 3 Affiliation(s) 1 Royal Perth Hospital, Perth, Australia . 2 Department of Engineering and Medical Physics, Royal Perth Hospital, Perth, Australia . 3 Princess Margaret Hospital, Perth, Australia . ABSTRACT Introduction: An observation was made that when removing self-tapping cortical screws from patients bones, stripping or shearing of the head of the screw occurred more often in screws whose cutting flutes sat in cortical bone compared with screws that had penetrated the distal cortex with flutes exposed. Method: A model was designed to simulate screws with their cutting flutes either in contact with cortical bone or deep to cortical bone. Screws were grouped depending on the location of their cutting flutes and removal torque wa...