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Biomedical subjects

V Strunz

Publications and source records attributed to V Strunz.

At least 19 recordsLinked to original sources
PubMed1989

Tissues at the surface of the new composite material titanium/glass-ceramic for replacement of bone and teeth.

A new composite implant material titanium/glass-ceramic was tested in rabbits using light microscopy, histomorphometry, and biomechanical testing methods. Two rabbit implant models were used. The first premolar tooth was replaced and cylinders inserted into the trabecular bone of the distal femur below the patella sliding plane. There was bone bonding to the glass-ceramic component and additional mechanical interlocking, due to bone ingrowth between the titanium matrix into secondary pores. This was proved by measuring the tensile strength at the interface of the new composite material which was in the same range as compared to pure glass-ceramic implants. In tooth replacement there was a tight attachment of gingival epithelium and stroma to composite titanium/glass-ceramic. These results are of particular clinical interest: physicochemical bone bonding and additional mechanical interlocking result in a resistance of the implant material against shear and tensile loads at the interface. Therefore this new composite material should be suitable for further load-bearing applications.

Animals↗
PubMed1985

The interface of various glasses and glass ceramics with a bony implantation bed.

Basing on histomorphological evaluations and morphometrical quantifications in a standardized model experiment, a comparison is made between the reactions of skeletal tissues to various glasses, glass-ceramics and enamels. On the surface of these so-called reactive biomaterials either a direct bonding to mineralized bone or also different amounts of osteoid or chondroid tissue formation can be observed, depending on the composition of the material. It is shown that the solubility of the glasses cannot directly be related to the reactivity and the resulting bone bonding; bone binds only to glasses with a controlled release of constituents and which exhibit a seam of extracellular matrix on their surface, in which normal primary mineralization can occur; the release of constituents such as Al2O3, Ta2O5, ZrO2, or phosphates from the material can inhibit this normal mineralization and the transformation of chondroid tissue to bone; if connective tissue instead of bone is present at the interface (either primarily or after bone remodelling), the dissolution (or corrosion) of the material may be no longer controllable, and the tissue reacts with a continuous inflammatory response to the corrosion products.

Animals↗
PubMed1984

Incidence of malformations of the urinary tract in association with clefts of lip, alveolus, and palate.

Malformation syndromes accompanied by cleft development in the lip-alveolus-palate (LAP) region are sometimes associated with anomalies of the efferent urinary tract. In the present clinical study, 68 children with an LAP-cleft were routinely subjected to radiological examination of the efferent urinary tract. These revealed pathological alterations, in varying degrees, in 26 children. The relationships between cleft type and urinary-tract malformation are analysed. The results show the significance of early interdisciplinary investigations.

Alveolar Process↗
PubMed1983

Does piezoceramic influence avian bone formation in the early postoperative phase?

Polarized and depolarized blocks of a piezoceramic composed of Pb (ZrTi)O3 are implanted in the diaphysis of the metatarsus of cocks. 15, 34, 55 and 84 days postoperatively, the implantation bed is histomorphologically examined, and the percentage of bone, osteoid and chondroid at the interface of the base and top area of the implants is morphometrically determined. The same types and the same amount of tissue develop with the same dynamics in the bed of polarized and depolarized piezoceramic. Therefore polarized piezoceramic has no positive influence on bone formation in the early postoperative phase.

Animals↗
PubMed1983

[Frequency of urinary tract abnormalities in cleft lip-maxilla-palate patients].

Malformations of the urinary tract favour urinary tract infection; on the other hand, a urinary tract infection is often the first indication of a malformation of the urinary tract. Further signs are externally visible malformations, such as cheilognathopalatoschisis. In two years we examined 53 children with schistases urologically and found urinary tract anomalies in 39,6%.

Adolescent↗
PubMed1981

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. Under circumstances not yet fully understood, the corrosion stops, and ground substance like material is deposited, which can be, at least partially, mineralized. After the disappearance of macrophages, chondroblasts, and/or osteoblasts lay down collagen fibrils and ground substance in which matrix vesicles are discernible, representing initial foci of mineralization. Areas with bone connection display collagen fibers and deposits of apatite crystals in close relationship to the bulk glass ceramic as well as small particles mainly derived from the glassy phase of the implant, providing the micromorphological substrate for the shearing and tensile strength of the interface between glass ceramic and bone.

Animals↗
PubMed1981

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. Primary mineralization was characterized by the occurrence of active forming cells, extracellular matrix vesicles and calcifying calcospheritic structures. Intensive primary mineralization in association with the implants indicates that glass-ceramic may be stimulative to ossification, allowing favorable tissue-implant relationship.

Animals↗
PubMed1980

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. Implants of KG S are anchored at an interface with bone connection, which is known to provide for application of considerable shear and tensile strengths; whereas, at the interface of ceramics of reduced solubility, soft tissue, chondroid and osteoid are mainly observed. The dynamics of the events at the interface indicate a disturbance of the transformation of chondroid cells into osteoblasts and of the mineralization of osteoid. This disturbance of pathophysiologic processes during bone healing or bone regeneration is discussed.

Animals↗
PubMed1980

[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.

Animals↗