The machining of cobalt-chromium alloy in partial denture construction.

PURPOSE: To investigate the performance of different rotary instruments when machining cobalt-chromium alloy.

MATERIALS AND

METHODS

One tungsten carbide bur, 1 diamond bur, and 2 aluminum oxide abrasive points (pink stones) of different diameter were used to machine cobalt-chromium alloy under standardized conditions. The rate of metal removal was determined and the resulting surfaces and bur wear were investigated using scanning electron microscopy and energy dispersive analysis.

RESULTS

Although the larger diameter pink stone was shown to be the most efficient instrument, the tungsten carbide bur produced the smoothest surface.

CONCLUSION

Because of its low cost and high cutting efficiency the pink stone is well suited for laboratory use. The tungsten carbide bur is the preferred instrument for clinical use.