PubMed Health⌕ Search

Biomedical subjects

M T Karagianes

Publications and source records attributed to M T Karagianes.

4 recordsLinked to original sources
PubMed1976

Use of 85Sr as an indicator of bone mineral replacement in dogs after disuse demineralization.

The left front legs of two beagle dogs were immobilized for 2 months; the right front legs of each were used as weight-bearing controls. Bone mineral replacement after immobilization was studied by giving intravenous injections of 85Sr. (Stroutium-85). After allowing the radioisotope to disappear from the soft tissues, measurements were made on only that remaining in the bone. The 85Sr uptake in the bone of the leg which had been immobilized was up to 400% higher than that in the control leg. This increased 85Sr uptake probably resulted from only a few percent loss in bone mineral during immobilization and suggests that losses of less than 1% can be detected and located. The sensitivity, simplicity and minimal radiation dose associated with this technique indicates potential application for use in human bedrest and space-flight studies.

Animals↗
PubMedDate not supplied

Development and evaluation of porous dental implants in miniature swine.

Organized bone ingrowth in endosteal porous implants fabricated from VMC titanium alloy and surgically implanted with a tight interference fit, securely anchored the implants in fresh and healed mandibular premolar sites of miniature swine. This bone-implant union retained its integrity under high as well as slight masticatory stresses up to one-year after implantation. Bone invasion of the alumina porcelain implants was impeded by the lack of adequate interconnecting porosity; when the porosity was increased, insufficient ceramic strength prohibited a tight initial bone-implant fit. As a consequence, inadequate initial implant stability resulted in a soft tissue encapsulation of the majority of the ceramic implants. Histological examination and mechanical testing results were similar for bone-ingrown implants exposed to different experimental stresses for 4, 5, 8, and 12 months. Bone ingrowth and interface shear strengths were also similar in the different VMC pore sizes and shapes investigated. The design of intraoral attachments appeared critical, at least in swine where no postoperative treatment was administered. Gingival inflammation and alveolar bone resorption caused by calculus were severe around truncated cone-shaped devices. Slender transgingival posts, occlusal caps, and crown restorations were less susceptible to calculus accumulation, resulting in a more satisfactory gingival and subgingival response. Excessive epithelial invagination was a problem only in implants with transgingival truncated cones. Good adherence of soft tissue to metal under the gingival mucosa prevented epithelial migration around implants with other transgingival devices. Alveolar bone resportion around the tops of bone-ingrown implants was minimal at the time intervals examined (up to one year); however, a definite conclusion should be delayed until longer-term implants under full occlusion are evaluated.

Aluminum↗