DENTAL ABRASIVES

By Dr.Swathi Pai on Friday 28 January 2011 with 1 comment



HISTORICAL ASPECT

The first diamond bur:
§  Before the 1890s, silicon carbide discs & stones were used to cut enamel because carbon steel instruments were inefficient at cutting enamel.
§  In 1897, William & Schroeder from the university of Berlin , Germany  were credited with making the first diamond dental bur .
§  Theses early burs were made by hammering diamond powder into the surface of soft copper or iron blanks.

The modern diamond bur:
§  W. H. Drendel, a German industrialist, who developed a process for bonding diamond points to stainless steel shapes or blanks, created the modern diamond bur in 1932.
§  By 1939, diamond burs were widely used in Europe & introduced in United States in 12 shapes, all in large sizes.
§  Widespread acceptance of diamond burs was limited from 1939 through 1946, because of the expense & impractical shapes & sizes then available.
§  The introduction of higher speed hand pieces & increasing co-operation among dentists, dental educators, the U S armed services & manufacturers led to the production of diamond burs that the profession could use at lighter cutting pressures, but with great efficiency.
§  The introduction & subsequent mass production of the high speed air –turbine dental contra angle hand piece  in 1957 was the stimulus for universal acceptance of diamond burs by the profession .

MANUFACTURE OF DIAMOND BURS

            Diamond burs have one or more layers of diamond chips attached to a shank that inserts into the hand piece .The shank usually is fabricated from a high strength metal such as tool steel, stainless steel or another alloy .The working end of the shank is machined to a specific shape or blank and the diamond chips are attached .The



dimensions & shapes of the blanks determine the ultimate size & shape of the finished product & are the basis for the numbering systems used by manufacturers.
The diamond chips are attached to the machined metal blank in various ways .The most common method used today is by Electrolytic deposition of natural or synthetic diamond particles with a matrix metal onto the blank.

Alternative attachment methods

§  Brazing
§  Sintering
  • Use of an adhesive - to attach diamonds to the blank
Abrasive instruments constitute the 2nd major category of rotary cutting instruments .The head of these instruments consists of a small angular particles of a hard substance held in a matrix of softer material. This softer matrix that holds the particles together is called BINDER

The abrasive should be distributed such that the surface of the tool wears away evenly . Different materials used for binder are: ceramic, metal, rubber, shellac etc. Rubber & shellac wears away easily & hence used for delicate abrasion like finishing & polishing. Cutting occurs at a large no: of points where individual hard particles protrude from the matrix, rather than along a continuous blade edge. (This difference in design causes definite differences in the mechanisms by which the two types of instruments cut). The abrasive should be distributed such that the surface of the tool wears away evenly. The wide spacing between the particles prevents the clogging of the debris.

The Abrasive instruments are grouped into:
1.      Diamond abrasives
2.      Other abrasives: (Eg; silicon carbide, boron carbide, aluminium
                                           Oxide, garnet, sand discs or stone)
     The diamond abrasives have great clinical impact in operative dentistry because of their long life & greater efficiency in cutting enamel & dentin.

Category: Conservative and Endodontics Notes , Conservative Dentistry Notes

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1 comments:

Gina Smith said...
Monday, December 12, 2011 11:31:00 AM

Fantastic article as far as the dental health is concerned.Everybody is very keen to have oral health today and for this dental health is most important.So Your article related to dental abrasives here is really a superb one.

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