Hand Cutting Instrument Used In Dentistry a2l2q

HAND CUTTING INSTRUMENT USED IN DENTISTRY

Introduction 

Many dental procedures require the use of hand

instruments with sharp cutting edges. This cutting instrument group used in operative dentistry includes : – – – – –

Excavators Chisels Hatchets Hoes Gingival margin trimmers. They are used in the cavity preparation of both amalgam and composite (resin) restorations.

Materials  The

hand cutting instruments are manufactured from two main materials : – – –

Carbon steel Stainless steel In addition some instruments are made with carbide inserts to provide more durable cutting edges.

Classification Chisels 2. Excavators 3. Special form of chisels 4. Miscellaneous 1.

Chisels 1. 2. 3. 4.

Straight Monoangle Biangle Triple angle

1.

Straight chisel :

– – – 

Straight plane line with shank. Primary cutting edge perpendicular to the long axis of handle Single plane instrument

Mechanism of action : – –

It can’t be right or left. It can be used both side.

Mono-angle :

2.

• • •

One angle between shank and blade Can be mesially or distally beveled. Otherwise same as straight chisel.

3.

Bin-angle : Two angle.

4.

Triple-angle : Three angle.

Bin-angle Chisel

Excavators  Hatchets  Spoon  Discoid  Cleoid

Hatchet Excavator •

Features :   

•

Mechanism of action :   

•

Cutting edge of the blade in the same plane with the handle. Single plane instrument. So it is direct cutting instrument. Bi-bevelled. Cut by being pushed or pulled in direction Can be used also in lateral cutting instruments Direct + lateral cutting used sometimes

Use : 

Delicate cutting within preparation in anterior tooth like sharpening of line or point angle or flattening the floor.

Hatchet Excavator

Hoe Excavator –

Design:  

–

Mechanical use :  

–

Primary cutting edge in perpendicular to the plane of handle. Single plane instrument. Vertical pull or push / direct cutting. Right and left / lateral cutting.

Use :  

Planning tooth preparation walls in case of class iii and class v cavity. Longer and heavier blade design are used for posterior tooth.

Cleoid –

Design :    

–

Movement :  

–

Shape of cutting edge like a claw. Blade comes to end-like points. They are double plane instruments. So lateral cutting instruments are made in pairs. Right and left cutting movement Lateral scrapping motion

Use :   

Excavation of soft caries Carving wax particles Deeper most caries removal, without harming pulp.

Cleoid Excavator

Discoid –

Design :   

–

Movement :  

–

Circular cutting edge. They are double plane instruments. So lateral cutting instruments are made in pairs. Right and left cutting movement Lateral scrapping motion

Use :   

Excavation of soft caries Carving wax particles Deeper most caries removal, without harming pulp.

Discoid Excavator

Special form of chisel      

 

Enamel hatchets Gingival margin trimmer Angle former Wedel-staedt chisel Off-set hatchet Off-set hatchets with cutting edges makin an angle other than a perpendicular angle with the long axis of the shaft. Triangular chisel Hoe chisel

Wedel-staedt Chisel

Enamel Hatchet • • • •

Same as ordinary hatchet. Special form of chisel. Hatchet shank has one or more angle, blade and cutting edge. Difference :  

•

Blade is larger and heavier and beveled on mesial/distal side. Ordinary hatchet is single plane instrument.

Use : 

Splitting and cleaving of undermined enamel.

G.M.T. (Gingival Marginal Trimmer) – Blade is curved as in spoon excavators. – Primary edge is at an angle to axis of the blade other than 90. – Double plane and single beveled. – Two pair instruments. – Total 4 instruments like :    

Mesial right side instrument Mesial left side instrument Distal right side instrument Distal left side instrument

 Mechanism of action : – Two plane instruments – primarily a lateral cutting instrument. – Trims margins of various walls.

Miscellaneous  Dental

probes.  Knives :  Gold knives.  Amalgam knives.  Finishing knives.

 Dental

files.

Dental Probe

Prepared by :  Dhairya

Patel  Abraham Johnson  Chandni Patel  Ravina Khimesra  Sejal Mehta