title: Nanostructured alumina-coated implant surface: effect on osteoblast-related gene expression and bone-to-implant contact in vivo.
abstract: OBJECTIVE
  The use of nanotechnology to enhance endosseous implant surfaces may improve the clinical control of interfacial osteoblast biology. This study investigated the influence of a nanostructure-coated implant surface on osteoblast differentiation and its effects on bone-to-implant contact (BIC) and removal torque values.
  
  
  METHODS
  Titanium disks were machined (M) or machined and subsequently treated by acid etching (Ac) or by dipping in an aluminum oxide solution (Al2O3). Surfaces were characterized by scanning electron microscopy, atomic force microscopy, and x-ray microanalysis. For the in vitro experiment, rat mesenchymal stem cells (rMSCs) were grown in osteogenic supplements on the disk surfaces for 3 days. Real-time polymerase chain reaction (PCR) was used to measure mRNA levels of several gene products (bone sialoprotein, osteocalcin, osteopontin, and RUNX-2). For the in vivo experiment, titanium implants were placed in rat tibiae and harvested after 3 to 21 days for measurement of bone-specific mRNA levels by real-time PCR. Removal torque and BIC were measured 3 to 56 days after placement.
  
  
  RESULTS
  Average height deviation (Sa, in nm) values for M, Ac, and Al2O3 implants were 86.5, 388.4, and 61.2, respectively. Nanostructured Al2O3 topographic features applied to machined implants promoted MSC commitment to the osteoblast phenotype. Greater bone-specific gene expression was observed in tissues adjacent to Al2O3 implants, and associated increases in BIC and torque removal were noted.
  
  
  CONCLUSIONS
  Nanostructured alumina may directly influence cell behavior to enhance osseointegration.
authors.affiliation: Department of Prosthodontics, Universidade Católica de Brasília, Brasília, DF, Brazil. mendonca@ucb.br
authors.forename: Gustavo
authors.initials: G
authors.lastname: Mendonça
authors.forename: Daniela Baccelli Silveira
authors.initials: DB
authors.lastname: Mendonça
authors.forename: Luis Gustavo Pagotto
authors.initials: LG
authors.lastname: Simões
authors.forename: André Luiz
authors.initials: AL
authors.lastname: Araújo
authors.forename: Edson Roberto
authors.initials: ER
authors.lastname: Leite
authors.forename: Wagner Rodrigues
authors.initials: WR
authors.lastname: Duarte
authors.forename: Lyndon F
authors.initials: LF
authors.lastname: Cooper
authors.forename: Francisco J L
authors.initials: FJ
authors.lastname: Aragão
mesh_terms: D000537:Aluminum Oxide / Q000008:administration & dosage* / Q000737:chemistry; D000818:Animals; D002454:Cell Differentiation / Q000187:drug effects / Q000502:physiology; D020099:Coated Materials, Biocompatible / Q000008:administration & dosage* / Q000737:chemistry; D050659:Core Binding Factor Alpha 1 Subunit / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D015921:Dental Implants; D020878:Device Removal; D005786:Gene Expression Regulation; D058574:Integrin-Binding Sialoprotein; D059630:Mesenchymal Stem Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D049329:Nanostructures; D016348:Osseointegration / Q000187:drug effects* / Q000502:physiology; D010006:Osteoblasts / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D015675:Osteocalcin / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D053495:Osteopontin / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D017207:Rats, Sprague-Dawley; D012795:Sialoglycoproteins / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D013499:Surface Properties; D013977:Tibia / Q000166:cytology / Q000601:surgery
chemical_list: D020099:Coated Materials, Biocompatible; D050659:Core Binding Factor Alpha 1 Subunit; D015921:Dental Implants; C546873:Ibsp protein, rat; D058574:Integrin-Binding Sialoprotein; D012333:RNA, Messenger; C493717:Runx2 protein, rat; D012795:Sialoglycoproteins; D015675:Osteocalcin; D053495:Osteopontin; D000537:Aluminum Oxide