03 hand cutting instruments/dental implants course by indian dental academy

cross section more pressure that is concentrated and more efficient the instrument will be.

Direct cutting and lateral cutting instruments: A direct cutting instrument is one in which the forces applied in the same plane as that of the blade and handle. It is a single planed instrument. Lateral cutting instrument is one in which the force is applied at the right angles to the blade and handle. These instruments have generally curved blades and called double planed instruments.

The single planed instrument may have two or more curves or angles in their shanks, all in the same plane to handle. Double planed instruments have an angle in the shank angle to the handle.

Single planed instruments can be used for direct and lateral cutting. Double planed instruments can be used for only lateral cutting.

Contrangling: In order to gain access, many instruments have the shank bent at one or more points to the angle the blade relative to the handle. The extent of this arrangement generally depends upon the length of the blade and degree of the angulation of the shank.

If the working point is moved out of the line of the axis of the handle and if it is more than 3 mm the instrument is said to be out of balance. To solve this problem in the modern instrument the shank is angled in such a way that the working end is placed within 3 mm of the long axis of the blade. This principle design is called contrangling.

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