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BioMed Research International
Volume 2013 (2013), Article ID 234093, 9 pages
http://dx.doi.org/10.1155/2013/234093
Research Article

External Mechanical Microstimuli Modulate the Osseointegration of Titanium Implants in Rat Tibiae

1Division of Bone Diseases, Department of Internal Medicine and Faculty of Medicine, University Hospital of Geneva, 1211 Geneva, Switzerland
2Laboratory of Biomaterials, School of Dentistry, University of Geneva, 1205 Geneva, Switzerland
3Laboratory of Applied Mechanics and Reliability Analysis, École Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
4Division of Bone Diseases, Department of Rehabilitation and Geriatrics, Av de la Roseraie 64, University Hospital of Geneva, 1211 Geneva, Switzerland

Received 12 July 2013; Revised 28 October 2013; Accepted 28 October 2013

Academic Editor: P. Bryant Chase

Copyright © 2013 Giovanna Zacchetti et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Purpose. To assess the effect of external mechanical microstimuli of controlled magnitude on the microarchitecture of the peri-implant bone beds in rat tibiae. Materials and Methods. Tibiae of forty rats were fitted with two transcutaneous titanium cylinders. After healing, the implants were loaded to 1 to 3 N, five days/week for four weeks. These force levels translated into intraosseous strains of , , and . After sacrifice, the implants’ pullout strength was assessed. Second, the bone’s microarchitecture was analyzed by microcomputed tomography ( CT) in three discrete regions of interest (ROIs). Third, the effect of loading on bone material properties was determined by nanoindentation. Results. The trabecular BV/TV significantly increased in an ROI of 0.98 mm away from the test implant in the 1 N versus the 3 N group with an opposite trend for cortical thickness. Pull-out strength significantly increased in the 2 N relatively to the nonstimulated group. Higher values of E-modulus and hardness were observed in the trabecular bone of the 2 N group. Conclusion. The in vivo mechanical loading of implants induces load-dependent modifications in bone microarchitecture and bone material properties in rat tibiae. In pull-out strength measurements, implant osseointegration was maximized at 2 N .