ABRASIVE MATERIALS

By Dr. Vishaal Bhat on Friday 28 January 2011 with 0 comments



CHALK:
A white colored abrasive composed of calcium carbonate. it is a mild abrasive in : Polishing enamel ,gold foil Amalgam .plastic material .

PUMICE:
Most common fine abrasive used in dentistry. Pumice obtained by crushing pumice stone. Flour of pumice used for polishing enamel, gold foil, amalgam & acrylic resins. Pumice powder mixed with water or glycerin is used by a revolving brush.
Slow speed recommended, otherwise the centrifugal force throws out most of the pumice from the brush.

CORUNDUM:
A form of Al2O3, usually white. Used primarily for grinding metal alloys. White stone is the most common form of corundum


EMERY:
·         This abrasive is grayish black corundum.
·         Mixture of AlO &Fe.
·         Commonly used as an abrasive coating on a cloth or paper disk
·         Used for finishing metal alloys & plastic materials.

GARNET:
·         Includes different materials such as Si or Al, Co, Fe, Mg &Mn.
·         Dark red in colour.
·         Extremely hard, making it a highly effective abrasive.
·         Used for grinding metal alloys & plastic materials
SAND:
·         Sand is predominantly silica
·         Irregularly shaped particles are obtained by crushing sand alone & are bonded to the paper with glue or resin.
·         It is supplied in the much familiar form – sand paper. Sand particles under air pressure are used to remove investment material from base metal alloy castings.
TRIPOLI:
Grey & red colored Tripoli are most commonly used in dentistry for polishing metal alloys & some plastic materials.
KIESELGUHR:
·         Used as fine abrasive on paper disc.
·         Used as filler in various impression materials.
·         Chronic exposure to this material causes Respiratory Silicosis.
CUTTLE FISH BONE:

·         A white calcareous product obtained from crushing the internal skull of a Mediterranean marine mollusc.
·         Available as coated discs &strips for polishing metal margins & amalgam restorations.
QUARTZ:
·         This is very hard, colorless & transparent.
·         Sharp angular particles of quartz are used for coating abrasive disks
·         Quartz abrasives are mostly used to finish metal alloys.
ZIRCONIUM SILICATE:
·         It is an off-white mineral used to make coated disks & strips. This forms an important component of the dental prophylaxis pastes.
SILICON CARBIDE (Carborundum):
·         The 1st synthetic abrasive manufactured by fusing sand & coke at 2000°c .The common form available are: Mounted points, coated disks &grinding wheels. They are green & blue black colour.
·         This wears away rapidly at high  heat; therefore should be kept wet when in use .

Category: Conservative and Endodontics Notes , Conservative Dentistry Notes , Dental Materials Notes , Prosthodontics Notes

POST COMMENT

0 comments:

Post a Comment