• G.V. Black is credited with the first acceptable nomenclature and classification of hand instruments.• His classification system enabled both dentists and manufacturers to communicate more clearly and effectively in regard to instrument design and function.
INSTRUMENTATION HAND INSTRUMENTS: Cutting Non-Cutting
HISTORY OF INSTRUMENTATION• In early Carbon Steel was primary used in instruments.• But it was harder material.• Nowadays stainless steel is main material.
Cutting Instruments• Before the invention of rotatory instruments Dentist could cut well shaped cavity using sharp hand instruments.• Drawback• Nowadays all tooth preparations are done with rotatory instruments• But hand cutting instruments are still important in finishing of tooth preparation.
DESIGN• Hand cutting instruments consist of three parts:• Handle• Shank• Blade• There is a slight angulation.
List Of Cutting Instruments• The terminology organized by GV Black is still used with some modifications.• He named the instruments according to their shapes.• He called all cutting instruments as Excevators.
Sharpening Of Hand Instruments• Look at the cutting edge in bright light.• Presence of “Glint” indicates edge is rounded or dull.
The cutting edge of the hand instrument shouldalways be kept sharp as dullinstruments1. Loss of control.2. More pain.3. Prolonged time for the operative procedure.4. Reduce the quality and precision of tooth preparation
Other Instruments• Mirrors• Explorers• Periodontal probes• Forceps
Instrumentation Grasps• Two types:• Pen grasp• Palm-thumb grasp
Pen Grasp• Provide more flexibility of movement• Most frequently used
Palm or thumb Grasp• Provide more control.• Thumb is placed at most top point.
Rotatory Instruments• Handpiece• Two types:• Straight• Contra-Angle
Straight• The long axis of bur is same as long axis of hand piece.• Used in laboratory as well as in clinics.
Contra-Angle• Primary handpiece used in mouth.• Head of handpiece is angled first away and then back toward ,the long axis of handle.
Types of Contra-Angle Hand piece• Low speed• 500-15000 rpm• Use for removal of carious dentin• High speed• 160,000-5,00,000 rpm• Use for cutting enamel and dentin