Tantalum radiography of the respiratory tract in dogs.
ALTHOUGH radiography of the respiratory tract was suggested by Chevalier Jackson in 1918 1 the full potential of this diagnostic aid has never been realized. The major drawbacks of the three radiopaque materials thus far employed in radiography of the airway 1-4 have been that:
Tantalum radiography in otolaryngology.
More than 50 patients with various lesions of the upper respiratory tract and two healthy volunteers were studied roentgenographically using powdered tantalum (1μ to 5μ) insufflated via catheter or intermittent positive pressure breathing apparatus, or both, after topical anesthesia with 5% cocaine and premedication with intramuscular atropine sulfate. Single frame and cine-radiographic studies demonstrated details of airway mucosa and were of assistance in deciding the appropriate course of therapy in most patients. Powdered tantalum may be an ideal radio-opaque contrast material in radiography of the upper respiratory tract and has potential as a research and clinical tool in otolaryngology.
Microstructure of the solder-casting zone in bridges of dental gold alloys.
The composition and structure were studied in the cast and in the solder of bridges which had failed clinically. Both materials were gold alloys but with different contents of Pt, Ag and Zn. The metallographic investigation revealed defects mostly in the solder, situated in the subsurface layer. SEM studied of the fracture surface revealed large porosites and a structure of dense parallel lines--striations--, indicating that the material had failed from fatigue. The materials in the fractured bridges were identified by micro-probe measurements. It was stated that cast material and solder material used together, were of different composition.