title: UV-A and UV-C light induced hydrophilization of dental implants.
abstract: OBJECTIVE
  Wettability is increasingly considered to be an important factor determining biological responses to implant materials. In this context, the purpose of this study was to compare the dynamic wettability of dental implants made from different bulk materials and modified by different surface modifications, and to analyze the respective changes of wettability upon irradiating these implants by UV-A or UV-C light.
  
  
  METHODS
  Four original screw-type implants were investigated: One grit-blasted/acid-etched and one anodically oxidized titanium, one zirconia and one polyetheretherketone implant. Additionally, experimental, screwless, machined titanium cylinders were included in the study. Part of that cylinders and of blasted/etched implants were further modified by a magnetron-sputtered photocatalytic anatase thin film. Scanning electron microscopy was used to investigate the surface micro- and nanostructures. Samples were treated by UV-A (382nm, 25mWcm(-2)) and UV-C (260nm, 15mWcm(-2)) for entire 40min, respectively, and their wettability was quantified by dynamic contact angle (CA) analysis from multi-loop Wilhelmy experiments.
  
  
  RESULTS
  All implants are characterized by submicron- and nanosized surface features. Unexposed implants were hydrophobic (CA>90°). Upon UV-A, solely the implants with anatase coating became superhydrophilic (CA<5°). Upon UV-C, the blasted/etched implants turned superhydrophilic, the anodized titanium and the zirconia implants were considerably (CA=34° and 27°, respectively) and the PEEK implants slightly (CA=79°) hydrophilized.
  
  
  CONCLUSIONS
  The wettability of implant surfaces can be improved by UV irradiation. The efficiency of UV-A and UV-C irradiation to lower the CA by photocatalysis or photolysis, however, is strongly dependent on the specific material and surface. Thus, attempts to photofunctionalize these surfaces by irradiation is expected to result in a different pattern of bioresponses.
authors.affiliation: Section Medical Materials and Technology, University Hospital Tübingen, 72076 Tübingen, Germany; Armed Forces Hospital, King Abdulaziz Airbase, Dhahran, Kingdom of Saudi Arabia.
authors.forename: Mohammed S A
authors.initials: MS
authors.lastname: Al Qahtani
authors.affiliation: Section Medical Materials and Technology, University Hospital Tübingen, 72076 Tübingen, Germany.
authors.forename: Yanyun
authors.initials: Y
authors.lastname: Wu
authors.affiliation: Section Medical Materials and Technology, University Hospital Tübingen, 72076 Tübingen, Germany.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Spintzyk
authors.affiliation: Institute for Manufacturing Technologies of Ceramic Components and Composites (IMTCCC), University of Stuttgart, Allmandring 7b, 70569 Stuttgart, Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Krieg
authors.affiliation: Institute for Manufacturing Technologies of Ceramic Components and Composites (IMTCCC), University of Stuttgart, Allmandring 7b, 70569 Stuttgart, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Killinger
authors.affiliation: Section Medical Materials and Technology, University Hospital Tübingen, 72076 Tübingen, Germany.
authors.forename: Ernst
authors.initials: E
authors.lastname: Schweizer
authors.affiliation: Section Medical Materials and Technology, University Hospital Tübingen, 72076 Tübingen, Germany.
authors.forename: Ingrid
authors.initials: I
authors.lastname: Stephan
authors.affiliation: Section Medical Materials and Technology, University Hospital Tübingen, 72076 Tübingen, Germany.
authors.forename: Lutz
authors.initials: L
authors.lastname: Scheideler
authors.affiliation: Section Medical Materials and Technology, University Hospital Tübingen, 72076 Tübingen, Germany.
authors.forename: Jürgen
authors.initials: J
authors.lastname: Geis-Gerstorfer
authors.affiliation: Section Medical Materials and Technology, University Hospital Tübingen, 72076 Tübingen, Germany. Electronic address: frank.rupp@med.uni-tuebingen.de.
authors.forename: Frank
authors.initials: F
authors.lastname: Rupp
mesh_terms: D001577:Benzophenones; D015921:Dental Implants; D057927:Hydrophobic and Hydrophilic Interactions; D007659:Ketones / Q000737:chemistry*; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D011092:Polyethylene Glycols / Q000737:chemistry*; D011108:Polymers; D013499:Surface Properties; D014025:Titanium / Q000737:chemistry*; D014466:Ultraviolet Rays; D017155:Wettability; D015040:Zirconium / Q000737:chemistry*
chemical_list: D001577:Benzophenones; D015921:Dental Implants; D007659:Ketones; D011108:Polymers; C063834:polyetheretherketone; D011092:Polyethylene Glycols; D015040:Zirconium; D014025:Titanium; C028541:zirconium oxide
keywords: Anatase; Dental implants; Hydrophilicity; PEEK; Photocatalysis; Roughness; Titanium; UV; Wettability; Zirconia