Instruments and techniques

INSTRUMENTS ANDTECHNIQUES

Dr. Mumena

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Tooth extraction instruments

Two types of instruments for simple extraction ofpermanent teeth and extraction of all primaryteeth, these are:

Dental forceps

Dental elevators

They are all made to conform to ISO (Internationalorganization of Standards).

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Dental forceps

Extraction instruments consisting of two blades witha joint to connect to the handle.

Many designs available

Designs fall into two groups:

Forceps for the Maxillary teeth:

Handle and beak of the forceps form more or less a straightline

Forceps for the mandibular teeth:

Handle form more or less a right angle with the beaks of theforceps

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Dental forceps cont….

Choice of forceps depends on

Morphology of the tooth

Root anatomy

Number of roots

Extraction is a surgical approach care must betaken when extracting tooth (Aseptic technique)

Instruments must be sterile before extraction

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Maxillary forceps

Forceps for upper teeth have:

Handles in the same long axis as the blades except forupper molars which is slightly sigmoid (Reason is toallow the beaks to align with long axis of the teeth)

Anterior teeth (Incisors & Canines) and retainedroots forceps have rounded tips

Shorter blade forceps can be used for canines becauseof their bulkier roots than anteriors

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Maxillary forceps cont…

Molar forceps have two broader blades

One is pointed or beaked

Recall morphology of maxillary molars (3 roots: 2buccal roots, one palatal)

Forceps are designed one for left side, another forright side)

Forceps has beaked and smooth blades

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Maxillary molars cont…

•Cont;

Beaked blade designed to fit into the trifurcationbetween mesiobuccal and distobuccal root (beak tocuccal

Smooth blade designed to approximate closely to thepalatal root

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Maxillary premolar forceps;

Blades and handle not in a perfectly straight line

Palatal and buccal lips of the blades consist ofsingle curves that conform to the curvature of theroot of the tooth.

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Maxillary anterior teeth:

Blades and handle in pretty straight line.

Inside of blades differ in that the palatal beak isslightly smaller and the area is also slightly smaller.

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Maxillary root forceps:

Blade is thinner (securing small root fragment).

Angle between blade and handle differ slightlydepending on the specific design.

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Lower teeth forceps

All the forceps have a straight handle at right angleto the blades

The blade pattern for anterior teeth (Incisors &canines) is the same for the upper teeth

They have rounded tips

Forceps for molars recall anatomy (Two roots)

Forceps have two beaked blades to fit between buccaland lingual root birfurcation (Mesial and Distal roots)

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Lower anterior forceps applied toone root of lower molars

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Mandibular forceps:

Mandibular molar forceps:

Both blades has protrusion/beaks to fit in betweenthe two roots of molars.

Variation in

wisdom teeth:

One for left 8 and one for right 8.

Another design is cowhorn;

beak has two conically bent parts that during extractionwedge in between the mesial and buccal roots (It is like thecow’s horn)

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Position of lower molar forcepsbeaks at the neck of tooth

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Use of forceps for extraction(Technique)

Successful extraction technique depends on:

Careful use of controlled force

Obtaining adequate access to the tooth

Creating unimpeded path of removal

Degree of force is greater for molars than for theanterior teeth,

care taken ensure that forceps blade shave closecontact with root surface

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Use of forceps for extraction(Technique)

Care taken:

Intimate contact of the whole inner edge of the beak tothe crown of the tooth is ideal (Correspond to the forceapplied).

Cross sectional shape of the root governs themovement the operator has to make to achieveextraction with forceps in close contact

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Use of forceps for extraction(Technique)

•E.g. incisors are thinner mesiodistally then buccolingual(movement

Movement should be in the plane the tooth is thestrongest (labiolingually)

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Elevators

Elevators are single bladed instrument used to aidextraction or complete extraction of tooth

Uses:

Luxation of tooth: widening periodontal ligamentmaking tooth mobile

Complete extraction of tooth or root:

Elevate tooth out of socket using bone as fulcrum (Not tooth)

There are many different types of elavators

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Elevators

Two common example of elevator are

Warwick james

Coupland

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Warwick James elevators

Have small operating hands

Available as left, right & straight

Tip inserted between the tooth root and the socketwall,

Rotational movement applied

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Warwick James elevators

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Warwick James elevating retainedprimary roots

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Couplands

Are available in straight pattern only

Three sizes only available (1, 2 & 3)

Can be used as bone chisels or to releaseperiodontal membrane

As chisel used to press gentle under the gingivalmargin of the tooth to be extracted

Used in rotational manner

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Couplands

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Use of elevators

Mechanical principles of elavator application are:

Lever

Wedge

Wheel and axle

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Elevators as lever

Elevator are used primarily as a lever

A dental lever is a dental mechanism fortransmitting a modest force, with the mechanicaladvantages of

a long lever arm and

a short effectors arm, into a small movement againstgreat resistance.

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Elevators as lever

When a dental elevator is used for tooth extraction,

a purchase point and a dental crane pick can be usedto elevate the tooth or a tooth root from the socket.

The small, straight dental elevator is frequentlyused to help mobilize teeth in a similar fashionwithout the preparation of a purchase point.

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Elevators as a wedge

Used as a wedge

Dental forceps is useful for the extraction of teeth in severaldifferent ways.

First, the beaks of the dental extraction forceps are usuallynarrow at their tips; they broaden as they go superiorly.

There should be a conscious effort made to force the tips ofthe dental forceps into the periodontal ligament space toexpand the bone and force the tooth out of the dental socket

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Elevators as a wedge

The wedge principle is useful when a straight dentalelevator is used to luxate a tooth from its socket.

A small dental elevator is forced into theperiodontal ligament space, which displaces theroot toward the occlusion and therefore out of thesocket

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Elevators used as a wheel and axle

This is most closely identified with the triangular, or pennant-shaped dental elevator.

When one root of a multiple-rooted tooth is left in the alveolarprocess, the pennant-shaped dental elevator is positioned intothe socket and turned.

The dental handle then serves as the axle and the tip of thetriangular elevator acts as wheel and engages and elevatesthe tooth root from the socket.

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Dental forceps

Principles of dental forceps use

The primary dental instrument used to remove atooth from the alveolar process is the extractiondental forceps.

Dental elevators may help in the luxation of a tooth,

But the instrument that does most of the work arethe dental forceps.

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Principles of dental forceps use

The goals of dental forceps use are two-folds:

expansion of the bony socket by use of the wedge-shaped beaks of the forceps and the movements of thetooth itself with the forceps, and

removal of the tooth from the socket, sometimes with theuse of dental microscopes.

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Tooth extraction:

The removal of teeth from the alveolar processemploys the use of several mechanical principlesand simple machines:

the lever, wedges, and the wheel and axle

Instruments for removing the tooth from the alveolarprocess (socket):

Dental extraction forceps (different types)

Dental elevators (different types)

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Principles of dental forceps use

There are five major motions that the forceps canapply to luxate the teeth and expand thebony socket:

Apical pressure.

Buccal pressure.

oLingual pressure.

Rotational pressure.

Tractional forces.

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Apical pressure.

Results in minimal movement of the tooth in an apicaldirection and expansion of the tooth socket by theinsertion of the beaks down into the periodontalligament space.

Thus apical pressure of the forceps on the toothcauses bony expansion.

A second major accomplishment of apical pressurewith the extraction forceps is that the fulcrum, thecenter of the tooth’s rotation, is places more apically.

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Apical pressure

Since the tooth is moving in response to the force placed on itby the forceps, the forceps becomes the instrument ofexpansion.

If the fulcrum is high, their is a larger amount of force on theapical region of the tooth, which increases the chance offracturing the root.

If the beaks of the forceps are forced a bit into theperiodontal ligament space, the center of rotation is movedapical, which results in greater movement of the expansionforces at the crest of the ridge and less force moving the apexof the tooth lingually. This process decreases the chance forapical root fracture.

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Buccal pressure.

Buccal pressure results in expansion of the buccalplate, particularly at the crest of the ridge.

It is important to remember that although buccalpressure causes expansion forces at the crest of theridge, It also cause lingual apical pressure.

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Lingual pressure.

Lingual pressure is similar to the concept of buccalpressure but is aimed at expanding the lingualcrestal born, at the same time, avoiding excessivepressure on the buccal apical bone.

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Rotational pressure.

Rotational pressure, as the name implies, rotates the tooth,which cause some internal expansion of the tooth, which causessome internal expansion of the tooth socket.

The teeth with single conical roots, such as the maxillary incisorsand mandibular premolars whose roots are not curved, aremost amenable to luxation and bony expansion by thistechnique.

Teeth that have other than conical roots or that have multipleroots-especially if those roots are curved- are more likely tofracture when using this type of pressure.

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Tractional forces.

Tractional forces are useful for delivering the toothfrom the socket once adequate bony expansion isachieved.

Tractional forces should be limited to the finalportion of the extraction process and should begentle.

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Conclusion:

there are a variety of forces that can be used toremove teeth.

A strong apical force is always useful and should beapplied whenever forceps are adapted to thetooth.

Most teeth are removed by a combination of buccaland lingual forces.

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Conclusion

Since maxillary buccal bone is usually thinner andthe palatal bone is a thicker cortical bone,maxillary teeth are usually removed by strong;buccal forces and less vigorous palatal forces.

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Conclusion

In the mandible the buccal bone is thinner from themidline posterior to the area of the molars.

The incisors, canines and premolars are removedprimarily as a result of strong buccal force and lessvigorous lingual pressure.

The mandibular molar teeth has stronger buccal boneand usually require stronger lingual pressure that theother teeth in the mouth.

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Conclusion

Rotational forces are useful for single rooted teeththat have conical roots and no severe curvaturesat the root end.

The maxillary incisors, particularly the centralincisors and the mandibular premolars especiallythe second premolars, are most amenable torotational forces

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