The ultrastructure of the interface between a glass ceramic and bone.

The interface of alkali-poor glass ceramic implanted in femora of male Sprague-Dawley rats shows soft tissue, chondroid, osteoid, and bone in connection with the implant. The ultrastructure of the interface with soft tissue mainly exhibits a corrosion process, during which the dissolution of the crystalline phase of the glass ceramic precedes the dissolution of the glassy phase. Macrophages are involved in this process phagocytosing debris of the glassy phase and removing as well as dissolving the remainders of the glass ceramic.

Primary mineralization and extracellular matrix vesicles in rat bone after administration of glass-ceramic implants.

Glass-ceramic implants were administered into cavities prepared in rat femoral shaft. Electron microscope examination revealed formation of collagenous rich matrix in the implant-bone interface. Features typical to primary mineralization as well as bone and implant resorption were present in the interface.

The anchoring of glass ceramics of different solubility in the femur of the rat.

A direct physicochemical bond between alkali-rich bioglass or glass ceramic (45 S 5 A and B, Hench) or alkali-poor glass ceramic (KG S, Brömer) and bone has been well documented. Since long-term studies have revealed the interface to be subjected to remodeling of the bone and to increased focal disintegration of the implant, glass ceramics of reduced solubility have been developed by lowering the Na2O content and adding Al2O3, Ta2O5, TiO2, and Sb2O3. Implants of glass ceramic KG S and different compositions with reduced solubility have been studied histologically 14, 29, or 30, 60, 119, and 245 days after implantation in the femur of male Sprague-Dawley rats.

[Tissue substitution in experimental oral surgery from a general viewpoint of pathology].

In experimental maxillo-facial surgery the replacement of large pieces of bone as a substitute for tissue is of special practical interest. The various possibilities of the interaction and connection between transplants and alloplastic implants in the surgical bed especially in bone are demonstrated under the aspects of general pathology and some proposals are given for a more precise terminology in this field. The application of dynamic load to implants is shown to be a leading factor for the development of the special biotechnical structure of a neoperiodontal ligament during the regeneration of tissue in the case of the dental rod implant.

[Tissue reactions to bioactive bone cement].

In the field of bone surgery, bone cement has gained a considerable importance for the fixation of osteosynthesis material. This paper deals with the investigation of a new bone cement which is mixed with bioactive glass ceramic. In comparison to the conventional bone cement, all data pertaining to the material are improved, and histological examinations reveal an osseous connection to the superficially located glass ceramic particles.

Lanthanon-induced hepatotoxicity and its prevention by pretreatment with the same lanthanon.

Intravenous injection of the light lanthanon praseodymium nitrate (10 mg/kg) into rats causes a marked liver toxicity which becomes manifest in hypoglycemia, inhibition of RNA and protein synthesis and accumulation of fat in liver tissue. All these effects can be nearly abolished by pretreating rats with a small dose (5 mg/kg) of the same lanthanon. This is neither due to a decreased uptake into the liver nor to an increased excretion rate of the lanthanon.

Effects of cadmium on the immune system of mice.

Chronic oral exposure of mice to Cd++ inhibits cell-mediated immunity of delayed type hypersensitivity induced by sheep red blood cells (SRBC). No effect was detected on humoral immune response to SRBC. Spleen cells derived from mice exposed to Cd++ showed in vitro enhanced response to T and B cell mitogens.

[Lupins - a new source of food for Andean countries. 5. Traditional methods of debittering of lupins by water].

The bitter taste of lupin alkaloids can be sensorially detected in water within ppm-range. The strength of the taste diminishes as follows: sparteine, D-Lupanin-perchlorate, lupinine, isolupinine and hydroxylupanine. The swelling capacity of lupin seeds presents different characteristics according to the species.

[The ultrastructure of ganglia and newly formed tendon sheaths].

Comparative electron microscopic examination of ganglions (from the tendon sheaths and joint capsules of the hand) as well as that of newly formed tendon sheaths (after resection of digital flexors and their tendon sheaths) indicate that both are the result of an adaptive effect of the mesenchyma which enables the formation of a new synovial organ in the presence of an adequate stimulus.

[Osteo-keramo-keratoprosthesis (author's transl)].

A high percentage of plastic keratoprosthesis is rejected again or intraocular infections occur because there is a cleft-like open junction between anterior chamber and lacrimal film. Only the ketratoprosthesis by Strampelli (1970) settles firmly in the cornea without the above risks, because the autogenous transplanted bone unites well with the grafted labial mucosa. 5 years of investigation have confirmed that glass ceramic Ceravital unites firmly with bones (Blencke et al.

[Coating of metal implants with the bioactive glass ceramics Ceravital].

The bioactive glass ceramic Ceravital forms a physicochemical bonding with bone which is capable of withstanding stress caused by tension. This glass ceramic may already be put to clinical use as replacement for minor osseous parts. However, physical data are limited for maximum stress withstanding or gracile whole ceramic implants.

Ultrastructural and histochemical investigations of spindle-shaped corpuscles in phagocytic cells of lymph nodes.

In connection with various diseases, spindle-shaped or roundish 2-15 micrometer large corpuscles with a yellowish-green, partly brown color are found in phagocytic cells of lymph nodes of various localisation. There are three groups according to staining and ultrastructural characteristics. I.

[Comparative studies on the adhesiveness to the bone of various implantation materials].

After earlier experiments showed that bone became adherent to glass ceramic, the maximum mechanical stress on the bone-ceramic interface, as compared with polymethylmethacrylate (PMMA) and aluminium oxide ceramic, was investigated for shearing force and tension. Whereas the PMMA and aluminium oxide ceramic test objects which had been inclosed in the connective tissue were very easily pushed out without measurable pressure, the average fracture load for 15 smooth glass ceramic objects was 466 p/mm2 in the pushed out test and 167 p/mm2 in the tension test.

[Staining of the surface layer in jaw tumors].

In the histological preparation for surface layer staining, saw cuts 100-300 micrometer thick of undecalcified bone or tooth are made with or without alloplastic implantation material. Only one side of the cut is stained for 4 hours. During this time the stain penetrates about 15 micrometer into the preparation.

[Dentomaxillary destructions in oxalosis].

Oxalosis, a rare metabolic disorder, leads to excessive formation of oxalate and deposition of calcium oxalate crystals in the tissue. This leads to renal insufficiency with resulting secondary hyperparathyroidism and myelofibrosis. In a 27 year old female patient, extensive destruction of the maxilla, mandible and teeth was observed which has not yet been described and which led to the loss of all teeth.

Surface staining of sawed sections of undecalcified bone containing alloplastic implants.

A simple new method is described for the histological evaluation of bones containing alloplastic implants of ceramic and/or metallic materials. The undecalcified bone is embedded in acrylic resin and sectioned at 50-200 micrometer using a sawing microtome. One surface of the preparation is stained up to 10 micrometer deep by floating the preparation on Giemsa stain.

[Jaw-enlargement with glass ceramics in the animal experiment].

The use of alloplastic material in the reconstruction of the defective or atrophic mandible appears obvious as the difficulties and risks of bone or cartilage transplants are well known. It appears that all the materials used up to now were demarcated by the bone as foreign bodies so that one could only observe strong union without a connective tissue line of separation with glass ceramics. In experimental operations in the pig, box shaped osteotomies were cut into the lower jaw and glass ceramic bodies were fixed into the clefts.