title: Effect of Photofunctionalization on Ti6Al4V Screw Stability Placed in Segmental Bone Defects in Rat Femurs.
abstract: OBJECTIVE
  Ultraviolet-mediated photofunctionalization is a new technology to improve bone and titanium integration. We hypothesized that photofunctionalization would enhance the stability of titanium screws used for segmental bone defects.
  
  
  METHODS
  Disks were prepared of a titanium alloy (Ti6Al4V) for an in vitro study to evaluate the attachment, proliferation, and differentiation of osteoblasts. Commercially available Ti6Al4V screws were used in vivo. Segmental bone defects were created in rat femurs as an immediate loading reconstruction model. The defects were reconstructed with commercially available titanium plates and Ti6Al4V screws, with or without photofunctionalization. The screw survival rates and mechanical stability were evaluated at 2 and 4 weeks, and the bone formation around the screws was analyzed.
  
  
  RESULTS
  Osteoblasts showed greater attachment, proliferation, and differentiation on the photofunctionalized Ti6Al4V disks. Photofunctionalized screws had significantly greater survival rates and mechanical stability at 2 and 4 weeks. The bone formation around the photofunctionalized screws was significantly greater than that around the untreated screws at 4 weeks.
  
  
  CONCLUSIONS
  The results of the present study have demonstrated the efficacy of photofunctionalization on enhancing the survival and stability of Ti6Al4V screws under a loaded condition in the reconstruction of segmental defects. This was associated with increased bioactivity and bone formation around the photofunctionalized Ti6Al4V material.
authors.affiliation: Associate Professor, Laboratory for Bone and Implant Sciences, The Jane and Jerry Weintraub Center for Reconstructive Biotechnology, Division of Advanced Prosthodontics, Biomaterials and Hospital Dentistry, University of California, Los Angeles, School of Dentistry, Los Angeles, CA; and Visiting Scholar, Department of Oral and Maxillofacial Surgery, Yokohama City University Graduate School of Medicine, Yokohama, Japan. Electronic address: mhirota@med.yokohama-cu.ac.jp.
authors.forename: Makoto
authors.initials: M
authors.lastname: Hirota
authors.affiliation: Visiting Scholar, Laboratory for Bone and Implant Sciences, The Jane and Jerry Weintraub Center for Reconstructive Biotechnology, Division of Advanced Prosthodontics, Biomaterials and Hospital Dentistry, University of California, Los Angeles, School of Dentistry, Los Angeles, CA.
authors.forename: Miyuki
authors.initials: M
authors.lastname: Tanaka
authors.affiliation: Visiting Scholar, Laboratory for Bone and Implant Sciences, The Jane and Jerry Weintraub Center for Reconstructive Biotechnology, Division of Advanced Prosthodontics, Biomaterials and Hospital Dentistry, University of California, Los Angeles, School of Dentistry, Los Angeles, CA.
authors.forename: Manabu
authors.initials: M
authors.lastname: Ishijima
authors.affiliation: Visiting Scholar, Laboratory for Bone and Implant Sciences, The Jane and Jerry Weintraub Center for Reconstructive Biotechnology, Division of Advanced Prosthodontics, Biomaterials and Hospital Dentistry, University of California, Los Angeles, School of Dentistry, Los Angeles, CA.
authors.forename: Chika
authors.initials: C
authors.lastname: Iwasaki
authors.affiliation: Visiting Scholar, Laboratory for Bone and Implant Sciences, The Jane and Jerry Weintraub Center for Reconstructive Biotechnology, Division of Advanced Prosthodontics, Biomaterials and Hospital Dentistry, University of California, Los Angeles, School of Dentistry, Los Angeles, CA.
authors.forename: Wonhee
authors.initials: W
authors.lastname: Park
authors.affiliation: Professor, Laboratory for Bone and Implant Sciences, The Jane and Jerry Weintraub Center for Reconstructive Biotechnology, Division of Advanced Prosthodontics, Biomaterials and Hospital Dentistry, University of California, Los Angeles, School of Dentistry, Los Angeles, CA.
authors.forename: Takahiro
authors.initials: T
authors.lastname: Ogawa
mesh_terms: D000497:Alloys / Q000737:chemistry / Q000528:radiation effects*; D000818:Animals; D001672:Biocompatible Materials / Q000737:chemistry / Q000528:radiation effects*; D001847:Bone Diseases / Q000601:surgery; D001860:Bone Plates; D001863:Bone Screws; D000069343:Bone-Implant Interface / Q000528:radiation effects*; D002448:Cell Adhesion / Q000502:physiology; D002454:Cell Differentiation / Q000502:physiology; D049109:Cell Proliferation / Q000502:physiology; D002478:Cells, Cultured; D005269:Femur / Q000601:surgery*; D008297:Male; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D010006:Osteoblasts / Q000502:physiology; D010012:Osteogenesis / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley; D019651:Plastic Surgery Procedures / Q000295:instrumentation; D013052:Spectrometry, X-Ray Emission; D013314:Stress, Mechanical; D016019:Survival Analysis; D013997:Time Factors; D014025:Titanium / Q000737:chemistry / Q000528:radiation effects*; D014466:Ultraviolet Rays
chemical_list: D000497:Alloys; D001672:Biocompatible Materials; C031462:titanium alloy (TiAl6V4); D014025:Titanium