OBJECTIVETo observe the long-term impact of calcium phosphate (CaP) sol-gel coating on bone growth around porous-surfaced implant.

METHODSThe porous-surfaced Ti-6Al-4V implants were prepared with the addition of a thin film of CaP sol-gel coating, and implanted into the tibiae of 8 rabbits, each with two implants. Implanted sites were allowed to heal for 2, 8, 12, and 24 weeks, after which specimens were obtained for scanning electron microscope analysis using the freeze-fracture technique.

RESULTSThe sol-gel coated implants recovered by freeze-fracture technique showed extensive bone growth from the endosteum along the implant surface. The bone was in direct contact with the CaP layer. The cement line-like layer was clearly demonstrated to be an intervening electron dense afibrillar layer between the CaP coat and the overlying newly deposited bone. The stability and osseointegration of the porous-surfaced implants seemed not to be affected by the osteoclastic resorption of CaP layer occurred during 24 weeks of healing.

CONCLUSIONBased on the findings in the long-term observation, the addition of a thin layer of CaP promotes an extensive osseointegrated interface between the porous-surfaced Ti-6Al-4V implants and the newly deposited bone.

Animals ; Calcium Phosphates ; metabolism ; Freeze Fracturing ; Gels ; Male ; Microscopy, Electron, Scanning ; Osseointegration ; Prostheses and Implants ; Rabbits ; Titanium

Drusen are small, yellowish deposits that form under the retinal pigment epithe lium with senescence or under certain pathological conditions. The present study examined these structures under the scanning electron microscope. Tissue came from the eyes of four donors, who were 22, 56, 60 and 61 years of age and who demonstrated widespread drusen of the posterior fundus. which was noted on postmortem examination. Specimens were prepared by detaching the retinal pig ment epithelium from Bruch's membrane and freeze fracturing the tissue. Drusen appeared as follows: 1. Distinct spherical masse, 10 X 9 um and 9 X 7 um in size, were situated between basement membrane of the retinal pigment epithelium and Bruch's membrane. The surface of the spherical masses were smooth. 2. Indistinct globular dome-like masses, with a harsh surface, were situated bet ween basement membrane of the retinal pigment epithelium and Bruch's membrane. These masses varied greatly in size. 3. Localized of dispersed small granular deposits of the inner collagen layer of Bruch's membrane were noted.
Aging ; Autopsy ; Basement Membrane ; Bruch Membrane ; Collagen ; Epithelium ; Freeze Fracturing ; Humans* ; Microscopy, Electron, Scanning* ; Retinal Pigment Epithelium ; Retinaldehyde ; Tissue Donors