title: Histological and histomorphometric evaluation of implant with nanometer scale and oxidized surface. in vitro and in vivo study.
abstract: BACKGROUND
  The biological fixation of an implant to bone is influenced by numerous factors, including surface chemistry and surface topography. Various methods have been developed to create rough implant surfaces in order to improve the clinical performance of implants and to guarantee a stable mechanical bone-implant interface. Anodic oxidation is a dental implant surface modification technique that results in oxide layer growth up to a thickness of 110 micron. The purpose of this study was to evaluate the performance of the surface through the osteoblasts cells growth and the influence of oxidixed surface on BIC percent, in the human posterior maxilla after 2 months of unloaded healing.
  
  
  METHODS
  In vitro commercially available primary human osteoblasts (NHOst) from both femur and tibia of different donor systems (Lonza Walkersville Inc, Walkersville, MD, USA) were grown in Osteoblast Growth Media (OBM) (Lonza). Osteogenic differentiation was induced for a period of 4 weeks by the OGM medium (OBM basal medium supplemented with 200nM of hydrocortisone-21-hemisuccinate and 7.5 mM of glycerophosphate). The viability of NHOst cells seeded test A and B was measured by the quantitative colorimetric MTT (3-[4,5-dimethyl-2-thiazolyl]-2,5-diphenyl-2Htetrazoliumbromide test) (Promega, Milan, Italy). One custom-made 2 x 10-mm site evaluation implant (SEI) with nanometer scale and oxidized surface (test) ( Evo Plan 1 Health s.r.l. - Amaro, UD, Italy), and one SEI with hydroxyapatite sandblasted surface (control) (Osseogrip Plan 1 Health s.r.l.  Amaro, UD, Italy), were placed in the posterior maxilla of 15 patients. Patients received one of each type of SEI placed on controlateral side.
  
  
  RESULTS
  The proliferation rate studied by the MTT assay showed that during the incubation time, starting at 24 h, an increased proliferation rate was evident in Test B respect to Test A. After 2 months of unloaded healing BIC percent was significantly higher in oxidized implants. BIC percent mean values for the Osseogrip surface was 36,133 +/-4,888 ER and 53,533 +/- 5,180 ER for the Evo surface(P = 0,028).
  
  
  CONCLUSIONS
  These results seem to confirm that implant surface topography entails mechanical restrictions to the spread and locomotion of the cells involved in bone healing.
authors.affiliation: Dental School, University of Chieti-Pescara, Italy.
authors.forename: V
authors.initials: V
authors.lastname: Corvino
authors.forename: G
authors.initials: G
authors.lastname: Iezzi
authors.forename: O
authors.initials: O
authors.lastname: Trubiani
authors.forename: T
authors.initials: T
authors.lastname: Traini
authors.forename: M
authors.initials: M
authors.lastname: Piattelli
mesh_terms: D000328:Adult; D049109:Cell Proliferation; D002478:Cells, Cultured; D015921:Dental Implants; D004311:Double-Blind Method; D006801:Humans; D010006:Osteoblasts / Q000502:physiology; D010084:Oxidation-Reduction; D014945:Wound Healing
chemical_list: D015921:Dental Implants