Early-stage osseointegration capability of a submicrofeatured titanium surface created by microroughening and anodic oxidation.
OBJECTIVE
The role of nanoscale/submicron morphological features in the process of osseointegration is largely unknown. This study reports the creation of a unique submicrofeatured titanium surface by a combination of anodic oxidation and sandblasting and determines how the addition of this submicrofeature to a microroughened surface affects the early-stage process of osseointegration.


METHODS
Nonmicroroughened implants were prepared by machining Ti-6Al-4V alloy in a cylindrical form (1 mm diameter and 2 mm long). Microroughened implants were prepared by sandblasting machined implants, while submicrofeatured implants were created by anodic oxidation of the sandblasted implants. Implants were placed into rat femurs and subjected to biomechanical, interfacial, and histological analyses at 1 and 2 weeks post-implantation (n = 6).


RESULTS
The submicrotopography was characterized by 50-300 nm nodules and pits in addition to other submicron-level irregularities formed entirely within the sandblast-created microstructures. The biomechanical strength of osseointegration increased continuously from week 1 to 2 for the submicrofeatured implants but not for the microroughened implants. A significant increase in bone-implant contact and bone volume, as well as a reduction in soft tissue intervention, were commonly found for the microroughened surface and the submicrofeatured surface compared with the nonmicroroughened surface. However, there were no differences in these parameters between the microroughened surface and the submicrofeatured surface. An extensive area of bone tissue at the submicrofeatured implant interface was retained intact after biomechanical shear testing, while the microroughened implant-tissue interface showed a gap along the entire axis of the implant, leading to clear separation of the tissue during the shear procedure.


CONCLUSIONS
This study demonstrates that a submicrofeatured titanium surface created by a combination of sandblasting and anodic oxidation enhances the strength of early-stage osseointegration, primarily because of the increased resistance of peri-implant bone tissue against external force rather than modulation of bone morphogenesis.
Laboratory of Bone and Implant Sciences, Weintraub Center for Reconstructive Biotechnology, Division of Advanced Prosthodontics, Biomaterials and Hospital Dentistry, UCLA School of Dentistry, University of California-Los Angeles, CA 90095, USA.
Masahiro
M
Yamada
Takeshi
T
Ueno
Hajime
H
Minamikawa
Takayuki
T
Ikeda
Kaori
K
Nakagawa
Takahiro
T
Ogawa
D000497:Alloys; D000818:Animals; D001696:Biomechanical Phenomena; D045662:Dental Etching; D003758:Dental Implantation, Endosseous; D015921:Dental Implants; D005269:Femur / Q000601:surgery; D020007:Implants, Experimental; D016348:Osseointegration / Q000502:physiology*; D010084:Oxidation-Reduction; D051381:Rats; D013499:Surface Properties; D014025:Titanium / Q000737:chemistry*
D000497:Alloys; D015921:Dental Implants; C031462:titanium alloy (TiAl6V4); D014025:Titanium