| 0086 Mechanical Loading of Osteoblasts: Strain Regimen and Substrate Chemistry | ||
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X.F. WALBOOMERS1, W.J. HABRAKEN1, L.C. WINTER1, B. FEDDES1, J.D. BUMGARDNER2, and J.A. JANSEN1, 1University Medical Center Nijmegen, College of Dental Science, Netherlands, 2University of Mississippi, Mississippi State, USA Objectives: To create the most suitable dental implant, a thorough understanding of the ankylotic connection with the surrounding bone is necessary. Many in vitro systems have been developed to study adaptation of bone cells upon loading. However, most studies apply only one (prolonged) period of mechanical loading, and use silicone (SIL) substrates, which is atypical for the situation around dental implants. Therefore, here we studied an intermittent regimen of mechanical strain, and Titanium (Ti) coated substrates. Methods: SIL dishes were subjected to a glow discharge treatment. A number of dishes were Ti-coated by radiofrequency magnetron-sputtering, and characterized with Rutherford backscattering spectrometry (RBS), and X-ray photoelectron spectroscopy (XPS). Osteoblast-like cells were cultured on the dishes, and were given: A-no stretching; B-60 minutes 4% cyclic stretching; C-60 minutes stretching on Ti; D-intermittent stretching (4 times 15 minutes). Up to day 24, proliferation, alkaline phosphatase (ALP) activity, and calcium (Ca) content were analysed. Specimens were observed with scanning electron microscopy (SEM), and confocal laser scanning microscopy (CLSM). All samples were present in 6-fold, and data were analyzed with ANOVA/Tukey tests. Results: The coating was 50 nm thick, did not delaminate, and contained Ti:O as 1:1. Cell detachment regularly was observed on SIL, but never on Ti-coatings. Proliferation significantly increased in response to Ti-coatings and to mechanical stretching, with intermittent strain showing the highest cell numbers. ALP activity was lower after loading, and on Ti-coatings. Lowest levels of Ca were found on Ti coatings, whereas highest levels occurred after intermittent strain. SEM revealed the abundant presence of collagen fibers and calcium phosphate depositions. CLSM confirmed that matrix formation was lower on Ti-coated substrates. Conclusions: 1-Osteoblast-like cells demonstrate increased responses to enlarged amounts of stimuli vs. prolonged stimuli. 2-Results obtained on silicone rubber substrates, can not be translated towards the situation around metallic implant materials. | ||
| Seq #16 - Cell Response 2:00 PM-4:00 PM, Wednesday, 10 March 2004 Hawaii Convention Center 328 | ||
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