Electronic Apex Locators

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ELECTRONIC APEX LOCATORSELECTRONIC APEX LOCATORS

LCDR Marc E. ArenaLCDR Marc E. Arena

03 February 200003 February 2000

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 Apex Locators Apex LocatorsSIRSIR

EDMUND HILLARY EDMUND HILLARY 

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 APEX LOCATORS APEX LOCATORS

Locating the ApicalLocating the Apical

Foramen withForamen with

Modern TechnologyModern Technology

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Electronic Apex LocatorsElectronic Apex Locators

HISTORY:HISTORY:

Suzuki (1942)Suzuki (1942)-- Consistent electrical resistanceConsistent electrical resistance

between instrument in a root canal and anbetween instrument in a root canal and an

electrode on the mucosa.electrode on the mucosa.

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Electronic Apex LocatorsElectronic Apex Locators

History:History:

The Resistance MethodThe Resistance MethodSunada (1962)Sunada (1962)

Root Canal Meter (1969)Root Canal Meter (1969)

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Electronic Apex LocatorsElectronic Apex LocatorsHistory:History:

Change in FrequencyChange in Frequency

Inoue (1971)Inoue (1971)

SonoSono--ExplorerExplorer

Not a type of SonarNot a type of Sonar

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Electronic Apex LocatorsElectronic Apex Locators

History:History:High FrequencyHigh Frequency

Hasegawa (1979)Hasegawa (1979)

EndocatorEndocatorable to make correct measurement in theable to make correct measurement in the

presence of conductive fluids withpresence of conductive fluids with

specially coated filespecially coated file

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Electronic Apex LocatorsElectronic Apex Locators

History:History: Voltage Gradient Voltage Gradient

Ushiyama (1983)Ushiyama (1983)

Maximum potential obtained at the apicalMaximum potential obtained at the apicalconstrictionconstriction

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Electronic Apex LocatorsElectronic Apex Locators

History:History:Relative Values of Frequency ResponseRelative Values of Frequency Response

 Yamaoka (1984) Yamaoka (1984)

 Apit (1989) Apit (1989)detects the apical constriction bydetects the apical constriction by

calculation the difference between twocalculation the difference between two

direct potentialsdirect potentials

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Electronic Apex LocatorsElectronic Apex LocatorsHistory:History:

Ratio MethodRatio Method

Kobayashi (1991)Kobayashi (1991)

Root ZX Root ZX 

Simultaneous measurement of the impedanceSimultaneous measurement of the impedance

of two different frequenciesof two different frequenciesthe quotient of which is expressed as thethe quotient of which is expressed as the

position of the electrode in the canalposition of the electrode in the canal

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ReliabilityReliability Apex locator is Apex locator is

more reliablemore reliablethan radiographthan radiograph

-- Pratten and McDonaldPratten and McDonald

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ReliabilityReliabilityRoot ZX Root ZX located Apex withinlocated Apex within

.5mm 84.72% of the time in.5mm 84.72% of the time in Vitro Vitro

--Ounsi and NaamanOunsi and Naaman

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ReliabilityReliabilityRoot ZX Root ZX located Apex withinlocated Apex within

.5mm 96.2% of the time in.5mm 96.2% of the time in Vivo Vivo

--Shabahang and othersShabahang and others

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ReliabilityReliability

Root ZX Root ZX 

more accurate than themore accurate than the

 Apit Apit

--Weiger and othersWeiger and others

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Using an Electronic Apex LocatorUsing an Electronic Apex Locator

Check electrical connectionsCheck electrical connections

Beware of cervical leakageBeware of cervical leakage Keep the pulp chamber dryKeep the pulp chamber dry

Keep the canal wetKeep the canal wet

Beware of high readings in long rootsBeware of high readings in long roots

Lateral canals may give false readingsLateral canals may give false readings

Not for use with open apex Not for use with open apex 

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Using The Root ZX Using The Root ZX 

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Using The Root ZX Using The Root ZX  Turn on the unit before plugging inTurn on the unit before plugging in

attachmentsattachments

Dry the pulp chamberDry the pulp chamber

 Advance the file until an apex reading is Advance the file until an apex reading is

obtainedobtained

Take multiple readings beforeTake multiple readings before

instrumenting the canalinstrumenting the canal

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Trouble ShootingTrouble ShootingCheck Check 

BatteriesBatteries ConnectionsConnections

 Volume adjustment Volume adjustment

 All parts clean and free of corrosion All parts clean and free of corrosion

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Trouble ShootingTrouble Shooting

The meter in the display does not moveThe meter in the display does not move

�� Calcified canalCalcified canal�� Canal obstructedCanal obstructed

�� Dry canalDry canal

�� Root form restricts navigationRoot form restricts navigation��  Apex surrounded by pustule Apex surrounded by pustule

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Trouble ShootingTrouble Shooting

Meter overreacts as file enters the canalMeter overreacts as file enters the canal

Large foramen (self correcting)Large foramen (self correcting)

Pulp chamber wetPulp chamber wet

PerforationPerforation

Small FileSmall File

Pulp in canalPulp in canal

File touching metal restorationFile touching metal restoration

Leaking restorationLeaking restoration

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Trouble ShootingTrouble Shooting

Meter gives erroneous readingsMeter gives erroneous readings

Retreatment of silver pointsRetreatment of silver points Large lateral canalLarge lateral canal

PerforationPerforation

Incomplete apex Incomplete apex 

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Electronic Apex LocatorsElectronic Apex Locators

Questions ?Questions ?

Comments ?Comments ?

Complaints ?Complaints ?

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Happy Mardi GrasHappy Mardi Gras