Nanostructured alumina-coated implant surface: effect on osteoblast-related gene expression and bone-to-implant contact in vivo.
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.
Mendonça
Gustavo
G
Department of Prosthodontics, Universidade Católica de Brasília, Brasília, DF, Brazil. mendonca@ucb.br
Mendonça
Daniela Baccelli Silveira
DB
Simões
Luis Gustavo Pagotto
LG
Araújo
André Luiz
AL
Leite
Edson Roberto
ER
Duarte
Wagner Rodrigues
WR
Cooper
Lyndon F
LF
Aragão
Francisco J L
FJ
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
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