title: Nitric acid passivation does not affect in vitro biocompatibility of titanium.
abstract: OBJECTIVE
  In general, both chemical composition and surface features of implants affect cell response. The aim of this study was to evaluate the effect of titanium (Ti) passivation on the response of rat bone marrow cells, considering cell attachment, cell morphology, cell proliferation, total protein content, alkaline phosphatase (ALP) activity, and bonelike nodule formation.
  
  
  METHODS
  Cells were cultured on both commercially pure titanium (cpTi) and titanium-aluminium-vanadium alloy (Ti-6Al-4V) discs, either passivated or not. For attachment evaluation, cells were cultured for 4 and 24 hours. Cell morphology was evaluated after 4 days. After 7, 14, and 21 days, cell proliferation, total protein content, and ALP activity were evaluated. Bonelike nodule formation was evaluated after 21 days. Data were compared by analysis of variance and the Duncan multiple range test.
  
  
  RESULTS
  Cell attachment, cell morphology, cell proliferation, total protein content, ALP activity, and bonelike nodule formation all were unaffected by Ti composition or passivation.
  
  
  CONCLUSIONS
  Although the protocol for passivation used here could interfere with the pattern of ions released from Ti-6Al-4V and cpTi surfaces, the present study did not show any effect of this surface treatment on in vitro biocompatibility of Ti as evaluated by osteoblast attachment, proliferation, and differentiation.
authors.affiliation: Department of Oral and Maxillofacial Surgery and Periodontology, School of Dentistry of Ribeirao Preto, University of São Paulo, Brazil.
authors.forename: Adriana C L
authors.initials: AC
authors.lastname: Faria
authors.forename: Márcio M
authors.initials: MM
authors.lastname: Beloti
authors.forename: Adalberto L
authors.initials: AL
authors.lastname: Rosa
mesh_terms: D000469:Alkaline Phosphatase / Q000032:analysis; D000497:Alloys; D000704:Analysis of Variance; D000818:Animals; D001672:Biocompatible Materials / Q000737:chemistry*; D001854:Bone Marrow Cells / Q000502:physiology; D002448:Cell Adhesion; D018929:Cell Culture Techniques; D002455:Cell Division; D048429:Cell Size; D003722:Dental Alloys / Q000737:chemistry; D008297:Male; D017942:Nitric Acid / Q000737:chemistry*; D010006:Osteoblasts / Q000502:physiology; D010012:Osteogenesis / Q000502:physiology; D011506:Proteins / Q000032:analysis; D051381:Rats; D017208:Rats, Wistar; D013499:Surface Properties; D013997:Time Factors; D014025:Titanium / Q000737:chemistry*
chemical_list: D000497:Alloys; D001672:Biocompatible Materials; D003722:Dental Alloys; D011506:Proteins; C031462:titanium alloy (TiAl6V4); D017942:Nitric Acid; D014025:Titanium; D000469:Alkaline Phosphatase