Instruments For Fixed Prosthodontics
Rotary Instruments For Tooth Preparation
Rotary instruments are used to grind the tooth (tooth preparation) to receive crown or fixed partial denture.
Table of Contents
Mainly two types of rotary instruments:
- Diamond points
- Tungsten carbide (TC) burs are used for tooth preparation.
They are available in various shapes and grits. The diamond points are classified as coarse, medium course, medium fine, and super fine and color coded as red, green, blue, and yellow, respectively. They are rotary instruments used with contra-angled handpiece. Diamond points are widely used for tooth preparation.
Read and Learn More: Preclinical Prosthodontics Notes
Diamond points to be used with micromotor handpiece and air-rotor handpiece are different. Diamond points used with micromotor handpiece have latch type nonworking end to attach it with micromotor. The diamond point or TC bur used with air rotor has straight nonworking end which is attached to air rotor due to friction grip.
Diamond Points
These are commonly used rotary instruments for tooth preparation. The basic tooth preparation kit includes straight fissure diamond, flat-end tapering diamond, roundend tapering diamond, torpedo-shaped diamond, long needle diamond, wheelshaped diamond, and flame-shaped diamond.
Contra-Angle Handpiece
This is motor driven handpiece. It gets power from electric micromotor. This handpiece has high torque and low speed. In contra-angle handpiece the head of handpiece is first angled away from the long axis and then back toward the long axis of the handle. Because of such design, bur head lies close to long axis of the handle of handpiece which improves visibility and accessibility to working field.
This design also improves stability while working. Bur or diamond points with latch type attachment/nonworking ends are used with contra-angle micromotor handpiece.
Air Rotor Handpiece
This handpiece gives very high speed but with lower torque than low speed handpieces. It has speed of 250,000–500,000 revolutions per minute (RPM). The high speed is achieved by small air driven turbine or rotor mounted in bearing the head of handpiece. The sank of the bur is inserted into the rotor of handpiece and revolves with it. The handpiece always contains a system which directs water spray at cutting end of the bur and often also contains fiber optic light for better visualization of operating field.
Friction Grip To Latch Convertor
This is small convertor that facilitates use of friction grip bur/diamond with contra-angle handpiece. On one end of the converter, latch mechanism is provided while on the other end there is provision to attach friction grip bur/diamond with converter.
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