INSTRUMENTS

Prof. Faten M Kamel

Bchd, Msc, Phd.

Removal & shaping of tooth structure are essential aspects of

restorative dentistry.Initially, it was a difficult task that

was accomplished entirely by hand instruments. Rotary &

powered cutting equipment was a major breakthrough in dentistry.

Instruments

• Hand cutting

• Rotary cutting

General classification of instruments

1. Instruments used for removal of tooth structure and restoration

2. Instruments used for manipulation and packing or condensation of restoration

3. Instruments used for finishing and polishing

4. Instruments used for isolation

5. Instruments used for miscellaneous purposes

Instrument design

Most hand instruments are composed of three parts:

1.      Shaft - it’s the part grasped by the operator hand - available in various sizes & shapes2.      Shank - connect the shaft to the working end of the instrument - may be straight, single, double or triple angled

3.      Blade/nib For many non cutting instruments, the part

corresponding to the blade is termed Nib. Some instruments have a blade on both ends of the handle & termed Double ended instruments.

The cutting edge

working part of the instrument, usually in the form of bevel with different shapes

The blade angle

angle between the long axis of the blade and the long axis of the shaft

The cutting edge angle

angle between the margin of the cutting edge and the long axis of the shaft

Hand instruments are named according to:

1. Purpose of use

2. Position of use

3. Form of its working

4. Angles on the shank

Instrument formula

1. First number: width of the blade in tenth of mm

2. Second number: length of the blade in mm

3. Third number: angle between the blade and long axis of shaft in centigrade

4. Fourth number: edge of the blade is at an angle other than 90º to the blade. It is placed next to the blade width