What is a Rotary Instrument?

A rotary instrument is an instrument that enables dental health professionals to remove or reduce tooth matter and dental materials and to shape teeth during various procedures.

The main types of rotary dental instruments are:

1) Burs - used in a high speed or low speed handpiece for cutting; usually made of tungsten carbide or diamond.

There are three parts to a bur:

    • Head – the working/cutting part; comes in many shapes and sizes
    • Neck – the narrow portion connecting the shank and the head; transmits the rotational force
    • Shank – the part that fits into the handpiece; comes in different types to fit different handpieces and also comes in different lengths for different usages

       

The head of the bur contains the blades or diamond grit,  which remove material.  The blades can be positioned at different angles to change the way the bur operates. Blades placed at more obtuse angles produce a negative rake angle which will increase the strength and longevity of the bur.  Blades placed at more acute angles produce a positive rake angle; this results in a sharper blade, but one which dulls more quickly.  Various diamond grits can be applied over a smooth shape for more or less aggressive material removal.

 

2) Finishing and Polishing Instruments – generally used in a low speed handpiece to reduce/shape material and finish or polish surfaces.  These include discs, strips, cups, points, and mounted and unmounted stones.

 

Did You Know?  Dentists typically spend between $2,500 and $8,000 per year on rotary instruments.  For some dental sales reps, rotary instruments represent as much as 25% of their annual sales.