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At least 19 recordsLinked to original sources
PubMed1979

Porous titanium endosseous dental implants in Rhesus monkeys: microradiography and histological evaluation.

Artificial tooth roots with porous surface coatings were fabricated by sintering spherical powder of titanium alloy to solid cylindrical cores. The tooth roots were implanted subgingivally in healed mandibular premolar extraction sites of fifteen Rhesus monkeys. Supracrestal abutments were screwed into pretapped holes in the superior aspect of the primary subgingival stage four to eight weeks after implantation of the root. Clinical evaluations were performed monthly. Ten animals were sacrificed for histological evaluation of the functioning free standing implants. Of twenty-nine implants placed, three were lost and four were rated failures on the basis of histological evaluation. Postmortem evaluations revealed bone growth into the porous surface coating of the primary stage of all the implants. The most characteristic features which could be used to describe differences in the implant histology were the buccal and lingual crestal bone heights measured in relation to the root porosity. Twelve of sixteen implants had crestal bone heights within one millimeter of the superior aspect of the root. Four other implants displayed excessive bone recession, revealing as much as one half of the root porosity supracrestally. The four implant failures could be related to unfavorable features of recipient bone sites. The results demonstrate that the bone growth into the porous surface coatings of artificial tooth roots is an efficacious method of dental implant fixation.

Alloys↗
PubMed1977

[A technic to prepare fixed ground sections for a quantitative microradiography study of the dentin].

The preparation of ground sections for the quantitative microradiographic study of dentine was carried out either by hand or by machine using a new technique of fixing the sections to the holder by a soluble adhesive. After setting up a method of control for the plano-parallelism of the sections, the times of preparation and the quality of the sections obtained with both methods were compared: engine grinding gave the best results in terms of both quantity and quality.

Dentin↗
PubMedDate not supplied

Microradiography of the collecting ducts in the perfusion fixed rabbit kidney: suggestions for the anatomic basis for the radiographic appearance of cortical striations and intrarenal reflux.

Perfusion fixation was used to preserve the rabbit kidney, in its in vivo state (open tubules). Barium sulfate was either injected through the renal artery at a pressure sufficient to cause postulated microruptures in the glomerular tufts and opacify the tubules, or refluxed via the ureter to opacify the collecting ducts and tubules to the level of Bowman's capsule. The anatomy of the collecting ducts and their relationships to the nephrons were demonstrated, allowing suggestions for the anatomical basis for the radiographic appearances of cortical striations and intrarenal reflux.

Animals↗
PubMed1978

Microradiographic study of cerebral and ocular aneurysms in hypertensive rabbits.

Cerebral and ocular microaneurysms were produced in rabbits made hypertensive by surgically induced silk-turpentine perinephritis combined with contralateral nephrectomy 7 days later. The aneurysms distributed throughout the brain and iris were studied by microradiography; a few representative aneurysms selected from the microradiographs were studied histologically. The microradiographic findings and histological sections correlated well. Intracranial microaneurysms were multiple and frequently located in the basal ganglia and near the cortex. Arterial changes in the iris paralleled intracranial arterial changes in degree and type except for the addition of hemorrhage around some microaneurysms. The results of this study show the potential of microradiography and histological sections guided by microradiography for studying the natural history of hypertensive arterial lesions and support the contention that hypertension, microaneurysms and intracerebral hemorrhages are related.

Aneurysm↗
PubMed1978

Bone changes induced by diphenylhydantoin in chicks on a controlled vitamin D intake.

Florid rickets developed in chicks receiving doses of diphenylhydantoin analogous to doses used in humans as anticonvulsants, vitamin D3 being given in amounts sufficient for normal bone mineralization in controls. The changes in the bones were directly related to the dose of diphenylhydantoin and inversely related to the dose of vitamin D3. Bone mineralization was assessed by roentgenography, histological examination, microradiography, and measurement of bone ash. Of these methods, roentgenography was the least sensitive. Rachitic changes were detectable by light microscopy and microradiography in chicks whose skeletons appeared normal roentgenographically. Roentgenographic evidence of rickets became detectable only when the rickets was far advanced. Rickets developed at serum levels of diphenylhydantoin similar to those found in patients taking anticonvulsant medication.

Animals↗