Characterization, at the bone crystal level, of the titanium-coating/bone interfacial zone.

Well integrated and clinically functional titanium dental implants retrieved in humans after 14 and 40 months of settlement were used for the characterization of the interfacial area between the plasma-sprayed coating and the surrounding mineralized bone. Electron microscopic studies were performed from undecalcified intact coating/bone interfaces. The concomitant presence of direct bone tissue apposition on the titanium coating, as well as the interposition of amorphous material along the same interfacial zones emphasizes the dynamic biologic aspect of the osseointegration process. A very striking finding of these ultrastructural and microanalytical investigations was the presence of tiny titanium grains ranging from 5 to 50 nm in diameter at the surface of bulky plasma-sprayed coating particles. High-resolution transmission electron microscopy revealed a continuity between the lattice planes of the coating material and those of the minute titanium grains; thus indicating a chemical binding. The thickness of the granular titanium layer interposed between coating particles and mineralized bone tissue ranged up to 600 nm. The observation of calcium-phosphate needle-like crystallites within the porous layer made of titanium grains indicates a bone ingrowth process, suggesting a bone-binding mechanism to the outer surface of the coated titanium implant.

[Long-term clinical evaluation of single tooth replacement by non-submerged implants].

OBJECTIVE: To evaluate single tooth replacement by the non-submerged osseointegrated dental implants. METHODS: In the time period from 1990 to 1998, 65 patients were consecutively admitted for treatment with a total of 104 ITI-implants supporting single crowns. RESULTS: No implant was lost during the healing phase, the 5-year cumulative survival rate was 99.1%. Prosthetic complications were loosening of screws for retention of abutment and fracture of octa-abutment. CONCLUSION: The non-submerged osseointegrated ITI dental implants can be a successful treatment in single tooth loss.

Characterization and histological analyses of a coral-collagen composite used for bone-replacement graft material: a report of clinical cases.

Several studies, devoted to the osteogenic potentialities of natural CaCO3 have already been reported. However, it seems questionable if the data obtained from natural calcium carbonates can be extrapolated to a composite biomaterial incorporating coralline material. For these reasons, in the present investigations the structural and crystallographic features of the biomaterial (Biocoral gel) were thoroughly analyzed prior to implantation, with the aid of X-ray diffraction and electron microscopy. Then, biopsied samples, taken from Biocoral gel-filled sites, respectively after 7, 8, 9, 12 and 29 mon implantation, were studied with optical and electron microscopy. It could be concluded from the histological analyses of the biopsies, that mineral still remained after long implantation periods. This composite biomaterial may thus be considered for uses in clinical situations where neither incorporation nor dissolution of the implanted biomaterial are essential, i.e. maintenance of edentulous ridge volume.

Matrix-assisted laser desorption ionization mass spectrometry: a new tool for probing interactions between proteins and metal surfaces. Use in dental implantology.

The fixation in the bone of an artificial titanium tooth root is believed to be initiated by the rapid adsorption of the proteins present in the surgical cavity on the titanium surface. The study of this adsorption should make it possible to predict the osseointegration capacities of new implant surface treatments. We describe here a new method, based on matrix-assisted laser desorption ionization-mass spectrometry (MALDI-MS), for quantifying proteins adsorbed on titanium surfaces fully identical to these designed for implantology. The key step of this method is a new MALDI-MS sample preparation allowing the adsorbed proteins to be removed from the surface and to be homogeneously dispersed in the matrix crystals. The adsorption of a model protein (lysozyme) on two titanium surfaces (polished and sandblasted) was studied in order to evaluate the method. The absolute MALDI-MS intensity was shown to vary linearly with the amount of adsorbed lysozyme. After dipping the titanium surfaces for different times in lysozyme solutions at different concentrations, the maximum amount of adsorbed lysozyme was measured by MALDI-MS and was shown to correspond to a lysozyme monolayer, which is consistent with results described in the literature.