DIAMOND ABRASIVE INSTRUMENTS

By Dr.Swathi Pai on Friday 28 January 2011 with 0 comments



Diamond instruments consists of 3 parts:

  • a metal blank
  • Powdered diamond abrasive
  • A metallic bonding material that holds the diamond powder onto the blank
               The blank in many ways resembles a bur without blades. Like any other rotary instrument, it has the same 3 essential parts:
    • Head
    • Neck &
    • Shank
The shank dimensions like those for bur shanks depend on the intended hand piece. The neck is usually a tapered section that connects the shank to the head. The head of the blank is undersized in comparison with the desired final dimensions of the instrument, but its size & shape determines the size & shape of the finished instrument .The abrasive diamonds may be natural or synthetic that is crushed to a powder of desired shape & size. The diamonds generally are attached to the blank by electroplating a layer of metal on the blank, while holding the diamonds in place against it. While electroplating holds the diamond in place, it also tends to cover much of the diamond surfaces.




MANUFACTURE


                  The diamonds are manufactured in multiple layers by electrodeposition, sintering or micro brazing & provides a continuous regeneration of the cutting surface as wear occurs.
BONDING AGENT
Serves the purpose of holding the abrasive particles together &attaches the particles to the metal blank. Most commonly used bonding agents for diamond instruments are ceramic & metals.

     CLASSIFICATION


In addition to the classification systems employed for the burs, the diamond instruments may also be classified on the average particle sizes of the abrasives
  • Coarse grit diamond burs              125 –150
  • Medium grit                                   88 -125
  • Fine grit                                          60 -74
  • Very fine grit                                  38 –44


HEAD SHAPES & SIZES

Diamond instruments are available in a variety of shapes &sizes that correspond to the burs except for the smallest diameter burs. Because of the presence of an abrasive layer on the underlying metal blank, the smallest diamond instrument cannot be as small in diameter as the smallest burs. Due to the lack of any standard & uniform nomenclature for diamond instruments, it becomes necessary to select them visually to obtain the desired shape & size and mention the catalogue number when describing it.


Diamond stones generally should not be used to cut metals or unfilled acrylic resins & their use should be limited to the reduction of tooth substance, baked porcelain & composite resin. Bur & diamond stones are readily cleaned, if they become clogged with debris. Diamond stones can be quickly cleaned by running them against a rubber wheel or pencil eraser. If blood from gingival has dried on the surface, simple immersion of diamond stone into a 3%peroxide solution will rapidly remove. If clogged dental burs can be easily cleaned with a scratch brush.

Category: Conservative and Endodontics Notes , Dental Materials Notes , Endodontics Notes , Featured

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