title: Can Resorbable Fixation Screws Replace Titanium Fixation Screws? A Nano-Indentation Study.
abstract: OBJECTIVE
  The aim of this study was to compare the nano-hardness and elastic modulus of titanium and resorbable screws and determine whether resorbable screws could completely replace titanium screws.
  
  
  METHODS
  The mechanical properties (nano-hardness and decreased elastic modulus) of TriMed titanium, resorbable Inion CPS, and Synthes RapidSorb samples were measured using a nano-indentation technique. In this study, a Hysitron TriboIndenter TI 950 with a resolution less than 1 nN and a displacement resolution of 0.04 nm was used for the nano-indentation tests. The unloading segments of the nano-indentation curves were analyzed using the method of Oliver and Pharr (J Mater Res 7:1564, 1992).
  
  
  RESULTS
  Statistical analysis showed that the values of the elastic modulus and nano-hardness of the TriMed titanium screws were significantly higher than those of the resorbable Inion CPS and Synthes RapidSorb screws (P < .05). A statistical difference was not observed between the values of the elastic modulus and the nano-hardness of the Inion CPS and Synthes RapidSorb screws (P > .05).
  
  
  CONCLUSIONS
  In this study, the resorbable screws were found to be soft and flexible compared with the titanium screw. According to the results of this nano-indentation study, resorbable and titanium screws cannot be used interchangeably.
authors.affiliation: Assistant Professor, Department of Oral and Maxillofacial Surgery, Faculty of Dentistry, Gaziosmanpaşa University, Tokat, Turkey. Electronic address: dt.ahmetaltan@gmail.com.
authors.forename: Ahmet
authors.initials: A
authors.lastname: Altan
authors.affiliation: Associate Professor, Department of Oral and Maxillofacial Surgery, Faculty of Dentistry, Mustafa Kemal University, Hatay, Turkey.
authors.forename: İbrahim
authors.initials: İ
authors.lastname: Damlar
authors.affiliation: Associate Professor, Department of Physics, Science and Art Faculty, Mustafa Kemal University, Hatay, Turkey.
authors.forename: Osman
authors.initials: O
authors.lastname: Şahin
mesh_terms: D020341:Absorbable Implants; D001863:Bone Screws; D055119:Elastic Modulus; D006244:Hardness; D008422:Materials Testing; D013314:Stress, Mechanical; D014025:Titanium / Q000737:chemistry*
chemical_list: D014025:Titanium