title: Titanium hydride and hydrogen concentration in acid-etched commercially pure titanium and titanium alloy implants: a comparative analysis of five implant systems.
abstract: OBJECTIVE
  Acid etching is a popular method to texture the surface of dental implants. During etching, the titanium oxide protective layer is dissolved and small native hydrogen ions diffuse into the unprotected implant surface. They enrich the implant surface with hydrogen and precipitate into titanium hydride (TiH). The aim of this study was to measure the concentration of TiH at the implant surface and the total concentration of Hydrogen at five commercially available implant systems, made of either commercially pure (cp) titanium or titanium alloy.
  
  
  METHODS
  X-Ray diffraction (XRD) was conducted on each implant system to determine the compounds present at the implant surface. Following a TiH(2)/Ti calibration curve, the concentration of TiH was determined. Concentration of hydrogen in the implants was measured by the inert gas fusion thermal conductivity/infrared detection method.
  
  
  RESULTS
  XRD data showed that TiH was present on all cp titanium implants but not on the alloyed implants. TiH concentration varied between 5% and 37%. Hydrogen concentration varied between 43 and 108 ppm, no difference in uptake was found between the cp titanium and alloyed implants. Low solubility of hydrogen in alpha-titanium is responsible for precipitation into TiH. Stronger etching conditions led to higher concentration of TiH2-x.
  
  
  CONCLUSIONS
  High solubility of hydrogen in the beta-phase of the alloy is preventing hydrogen from precipitating into TiH. All implants, even those lacking TiH at the surface, were enriched with hydrogen. In all implants, hydrogen concentration was within the normative limit of 130 ppm.
authors.affiliation: Department of Stomatology & Maxillo-Facial Surgery, University of Paris, Paris, France. ssm@bluewin.ch
authors.forename: S
authors.initials: S
authors.lastname: Szmukler-Moncler
authors.forename: M
authors.initials: M
authors.lastname: Bischof
authors.forename: R
authors.initials: R
authors.lastname: Nedir
authors.forename: M
authors.initials: M
authors.lastname: Ermrich
mesh_terms: D000134:Acid Etching, Dental / Q000379:methods*; D000497:Alloys; D000537:Aluminum Oxide / Q000737:chemistry; D011232:Chemical Precipitation; D003722:Dental Alloys / Q000737:chemistry*; D045662:Dental Etching; D015921:Dental Implants; D003764:Dental Materials / Q000737:chemistry*; D006358:Hot Temperature; D006801:Humans; D006851:Hydrochloric Acid / Q000737:chemistry; D006858:Hydrofluoric Acid / Q000737:chemistry; D006859:Hydrogen / Q000737:chemistry*; D007259:Infrared Rays; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D011522:Protons; D012995:Solubility; D013464:Sulfuric Acids / Q000737:chemistry; D013499:Surface Properties; D013814:Thermal Conductivity; D013997:Time Factors; D014025:Titanium / Q000737:chemistry*; D014961:X-Ray Diffraction
chemical_list: D000497:Alloys; D003722:Dental Alloys; D015921:Dental Implants; D003764:Dental Materials; D011522:Protons; D013464:Sulfuric Acids; C031462:titanium alloy (TiAl6V4); D006859:Hydrogen; D014025:Titanium; D000537:Aluminum Oxide; C033158:sulfuric acid; D006851:Hydrochloric Acid; D006858:Hydrofluoric Acid