dental elevators

Dental Elevators

Indications • To reflect muco periosteal flap• Luxate the tooth which cannot be removed with forceps like 1. Removal of impacted teeth - 2. Removal of malposed teeth 3. Removal of extensively decayed teeth4. Removal of anteriorly tilted teeth• Loosen teeth before forceps application• To split teeth once a bur groove has been placed• To remove intra radicular bone • Removal of retained root• To remove the fractured roots ( gingival, middle , apical)

Classification • According to form- straight - Angular- Cross bar type

Principles for use of elevators

1. Lever principle 2. Wedge principle3. Wheel and axle principle

Components

Three components – • Handle • Shank• Blade

Components Handle • Handle large size to facilitate a good grip on the instrument while

working. • It may be 180 0 to the shank eg. straight elevator or at right angles

to the shank(cross bar elevator)

Shank • It connects handle to the blade • It should be strong enough to withstand and transmit the forces applied

to the handle.

Blade• Working tip• Used to transmit forces to the tooth or root• Blade might be straight , triangular or pick type

Level principle

Depending on the position of the fulcrum the lever may be divided into

• First order ,

• Second order and

• Third order levers.

Lever principle

Effort arm (a)

Lever arm(b)

Lever arm

Effort arm

Lever principle

In case of elevators ,• the handle of the elevator is the Effort arm, • the place where the elevator touches the crestal bone is the

Fulcrum and

• the point where the blade of the elevator contacts the tooth, is the Resistance

Lever principle • Maximum mechanical advantage is gained by keeping the

effort arm longer than the resistance arm

• Moving the fulcrum closer to the side where the effort is exerted increases the force required to lift the same object

• For eg to lift a heavy load from the ground with a stick , if the fulcrum is kept closer to the side where the effort is exerted( short effort arm ) , the effort exerted has to be much more to lift the load.

• On the other hand longer effort arm, lesser the effort to lift the same load

Lever principle

Effort arm (a)

Lever arm(b)

Mechanical advantage= Ratio of length of long arm(a) to the length of the short arm(b)Resistance (R) to effort( E)

Mechanical advantage = a/b : R/E = 3 if calculations are made based on the actual dimensions of an elevator , it is seen that each pound of pressure applied on the effort arm is multiplied by 3 times using lever principle

R

E

Wedge principle • Wedge is comparable to a movable inclined plane in which ,

when the effort is exerted at the base of the inclined plane, the resistance is seen on the slope side of the inclined plane .

E

Resistance is at right angles to the applied Effort

Wedge principle • The wedge elevator is forced between the root and the bone,

parallel to the long axis of the tooth

• wedge is a movable inclined plane which overcomes a large resistance at right angles to the applied effort

• Usually used in conjunction with the lever principle

Wedge principle

Mechanical advantage = length of slope (a)

Height of the base of inclined plane (b)

a/b = R/E = 2.5 timesIf calculations are made based on the actual dimensions of an elevator , it is seen that each pound of pressure applied on the effort arm is multiplied by 2.5 times using the wedge principle.

Wheel and axle principle • This works on a principle resembling a wheel of a vehicle

which is attached to a axle around which the wheel moves.• • A small rotation of the wheel creates a large rotation of the

axle which helps to lift the load

Mechanical advantage• When the blade of the elevator engages on to the tooth (load)

and the handle (which serves as wheel) is rotated, the force created on the blade of the elevator (which serves as the axle) is multiplied , created a greater mechanical advantage to elevate the tooth out of socket.

ME = Ratio of radius of the wheel(a) radius of the axle(b)

• ME= a/b = R/E = 4.6 Maximum mechanical advantage

Rules to be followed while using the elevators -

• Never use the adjacent tooth as the fulcrum, unless that adjacent tooth is also to be extracted

• Never use buccal cortical plate or lingual cortical plate as the fulcrum

• Only the crest of the alveolar bone is to be used as fulcrum

• Always use finger guards to protect the soft tissues if the elevator slips.

Rules to be followed while using the elevators -

• Support the shank of the elevator with the index finger to control the forces applied to the elevator

• Do no cross the midline when applying the elevator

• Always elevate from the mesial side of the tooth

• The concave or flat surface of the elevator faces the tooth / root to be elevated

Type of Grips used in application of elevator

Palm gripUsed for heavy forces where the handle rests against the heel of the palm

Finger grip Used for delicate applications

Elevators used in removal of tooth

Straight elevators

Eg coupland elevator • Large pear shaped handle with straight shank • Blade and shank in same plane • Shank narrows down in dimension gradually from handle to

blade • The blade has concave groove on one side, that faces tooth to

be elevated

• Based in lever and wedge principle

Coupland elevator

Coupland elevators - blade

Uses • To luxate impacted or mal-aligned teeth prior to forceps

extraction.• Working of this elevator is based on wedge principle and first

order lever principle.• The elevator is placed at 45 degree angle to the long axis of

the tooth with concavity of the blade facing tooth to be extracted

• The crest of the inter septal bone is used as fulcrum• It also may be applied parallel to long axis of the tooth when it

is wedge into the periodontal ligament space to luxate the tooth.

Removal of premolar using straight elevator

Hospital pattern elevator

Description

• The blade, handle and shank are in same plane.• Handle design is different from other elevators – it is flat,

triangular in shape with deep criss cross groves for an enhanced grip.

• The second is an smooth inclined al the way from the handle and the blade with an enhanced inclination closer to the tip.

• One side of blade is flat and has vertical serrations.• Other side of blade is convex and tip is pointed

Hospital pattern

Hospital pattern - blade

Uses • To luxate tooth prior to placing forceps

• The serrated flat side of the blade is placed facing the tooth to be extracted.

• It is placed at a 45 degree angle to the long axis of the tooth or may alternatively be wedged into the periodontal ligaments space vertically along the long axis of the tooth.

• This elevator works based on the wedge and 1st order lever principle.

Straight elevator

Cryer’s elevators • Offset blade – as the blade is at an angle to the shank and

handle.

• Blade is curved and triangular in shape with the pointed tip

• The working tip is angulated, with one convex and another flat surface.

• The flat surface is the working side

• Based in lever and wedge principle

• This elevator is available in pairs.

Cryer ‘s elevator

Uses• To remove impacted molars – the pointed tip is placed in buccal

furcation to luxate the tooth from the socket.

• To remove the fracture root tips in mandibular molars

• When one root tip of mandibular is fractured, the elevator is placed in to empty alveolar socket of the root which is removed. The inter radicular is first removed and then tip of elevator is engaged into the cementum of the fracture root.

• To assist removal of erupted maxillary third molar. Forces displaced the tooth in a distal, buccal and occlusal direction.

Cryer’s elevator

Cryer’s elevator

Winter’s cross bar elevator

• The blade appears similar to cryer’s elevator

• Offset blade design where blade is at an angle to shank

• Shank is at right angles to the handle

• Working tip is at an angle to the shank

• Flat surface is the working side

• Works on Wheel and axle principle

• This elevator has maximum mechanical advantage due to the cross

bar handle and the offset blade design

Blade – offset design

The blade is curved and triangular in shape and has a convex and a flat surface

Winter’s cross bar elevator

Uses of crossbar elevator • Used with rotational forces based on wheel and axial

principles• Used for removal of impacted mandibular tooth • Used with caution for removal of impacted mandibular third

molar as the force may cause fracture of the angle region of mandible.

• Used for removal of root fragments of mandibular molars similar to the way, a cryer’s elevators is used.

• Not used in maxillary arch.

Crossbar elevator

Warwick James • handle is less bulky and flat • Comes in set of 3 elevators • Has convex and flat surface . Flat surface is the working

surface• Working blade is at an angulation to the shank or straight • Available in Straight, right and left • Looks like hockey stick

Warwick James

Apexo elevators • These straight elevators of offset blade. • Blade is at an angle to the shank• The blade is narrow with concavity on one side and ends in a

sharp pointed tip.• It has large pears shaped handle.• Paired – right and left

Apexo elevators

Uses • To remove fracture root fragments at the cervical, middle or

apical one third.

• The pointed tip and concave surface of the blade is wedge between the tooth fragments and the alveolar bone from the mesial and distal aspect with the slight push motion.

• This elevator works based on the wedge principle.

Apexo elevator

Complications • Damage or extraction of adjacent tooth • Fracture of maxilla and mandible • Fracture of alveolar bone • Slippage of instrument leading to damage to adjacent

structures • Puncture wounds • Root forced into antrum • root forced into mandibular canal • Root displaced into space