2010 #3 Care of Metal Crown Restorations Author: Crowder Flashcards
What instrument and at what angle is used for the final step of margination?
Stone lubricated with silicon grease using the contra angle on a slow speed handpiece moving from the metal crown to the tooth at a 45 degree angle
Why should ultrasonic scalers be avoided on metal restorations?
Contributes to etching, scratches, pitting and deformation of the metal
What instruments should you use on crowns instead of ultrasonic scaler?
Subgingival scaling using ultrasonic and hand instruments ok Use a prophy cup on a slowspeed to polish metal
What kind of polish should you use for metal crowns?
Tin oxide prophy powder Regular prophy polishing cup Robinson brush mounted on a slow speed handpiece Fine grit rubber point with silicon carbide for shine
What are the base metals in dentistry?
Titanium, Nickel, Copper, Silver* and Zinc
*Silver reacts with oxygen water and sulfur to form silver sulfide and is not often considered a noble metal in dentistry
What are the noble metals?
Gold, palladium, platinum, iridium, rhodium, ruthenium and Osmium
Au, Pd, Pt, Ir, Rh, Ru, Os
What are examples of 2 body abrasives?
Abrading burs, bonded abrasives like rubber points with silicon carbide or coated abrasives
What are 3 body abrasives?
Abrasives that have small pieces of loose material circulating within the contact zones of the abrasive and the substrate like polishing paste, tin oxide in glycerin, an aluminum oxide slurry or diamond polishing paste
What is Tripoli and where does it come from?
Common polish used in metal restorations that originates from porous rocks from North Africa
What is rouge polish?
A fine red powder of iron oxide usually applied with a soft cloth wheel to polish metal crowns.
