The bone–titanium interfacein vitro

Abstract

Commercially pure 5-mm-diameter titanium (cpTi) discs received droplet inoculations of cells derived from rat bone marrow and were maintained in supplemented culture medium for 2-3 weeks. The cells and extracellular matrix (ECM) were processed for observation by light (LM), scanning (SEM), and transmission electron (TEM) microscopy. The latter was achieved by freeze-fracturing the solid metal from the resin-embedded tissue using a method which preserved the interface. Surface staining of whole discs revealed cells separated from the metal substratum by areas of ECM which stained positively using von Kossa's method to identify mineralization. At SEM, the ECM comprised dense interwoven collagen fiber networks which were partially obscured by globular masses (GMs). Individual GMs were associated with collagen fibers, especially at fiber intersections. EDAX line scan analysis confirmed the presence of Ca and P in these areas which were assumed to be spheritic foci of calcification since the Ca and P peaks diminished in areas which demonstrated only collagen fibers or the underlying cpTi. TEM examination confirmed the presence of globular mineralization and also revealed the presence of an interfacial zone between the metal substratum and the mineralized ECM elaborated by osteoblasts during the culture period. The interfacial zone comprised two layers, a bonding zone containing few collagen fragments and a ruthenium red positive layer containing more densely packed collagen fibers. We believe that this is the first report of both the formation of bonelike tissue on solid titanium substrata in vitro and demonstration of an interface which bears close morphological similarities to that known to develop in vivo.

Tensile bond between bone and titanium: A reappraisal of osseointegration

“…Generally it is not believed that there is a direct chemical bond between titanium and bone tissue, but when the term osseointegration was coined by Brhnemark in the 1970s, a chemical bond may have been implied. Later, ultrastructural studies indicated an amorphous ground substance at the bone-implant interface, which appeared not to support the idea of a chemical bond , Linder 1989a, b, Davies et al 1990). Osseointegration then became defined as contact between implant and bone without an intervening fibrous tissue layer at the interface, on the light microscopic level (Carlsson et al 1986).…”

Formation of hydroxyapatite on titanium implants in vivo precedes bone-formation during healing

“…This layering has been confirmed by previous studies, showing crystals of HA beneath the cells. 5,8 The inner stratum of Ca on the Ti surface has been described previously after analysis of the bone-implant interface of healed-in implants by atom probe tomography. 19 This analytical method can only detect basic elements and does not provide molecular information.…”

“…Consequently, the bone-titanium implant border has remained an object of continuous study during four decades. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15] However, studies of the established material/bone interface cannot give definite answers to the time-dependence of the subprocesses of bone formation. The only possible way to obtain this information is to make time-lapse studies of bone healing at implants.…”

Effects of Ionizing Radiation on In Vitro Differentiation of Osteoblasts Derived from Rat Bone Marrow Stroma

“…Osteoblasts derived from rat bone marrow stroma were isolated from the femurs of young adult male Wistar rats weighing approximately 120 g (Japan Clea Co., Ltd., Tokyo, Japan), according to the method of Maniatopoulos et al 15,16 For the primary culture, both femora were removed and washed 4 times in α -minimal essential medium containing antibiotic solution (1.0 mg/mL penicillin G, 0.5 mg/mL gentamicin, and 3.0 μg/mL amphotericin B). The epiphyses were then cut from both femora, and the marrow cells were flushed out with 30 mL of α -minimal essential medium supplemented with 15% fetal bovine serum, 10 mM β -glycerophosphate, 10 −8 M dexamethasone, 50 μ g/mL ascorbic acid, and antibiotics at one tenth of the concentrations listed above.…”

“…In the culture system used in this study, 15,16 mesenchymal stem cells were included in the rat bone marrow stroma isolated from the femora. Mesenchymal stem cells differentiate into osteogenic cells, and osteoprogenitor cells differentiate into osteoblasts.…”