Foramen LastForamen Last

eliminates constrictions in the coronal region cleans coronal 2/3’s of canal b/4 apical 1/3 is entered limits the engagement of each file ~ 2-5mmlimits the engagement of each file ~ 2-5mm reduces the impact of canal curvature better tactile awareness during apical shaping

eliminates constrictions in the coronal region cleans coronal 2/3’s of canal b/4 apical 1/3 is entered limits the engagement of each file ~ 2-5mmlimits the engagement of each file ~ 2-5mm reduces the impact of canal curvature better tactile awareness during apical shaping

allows greater volume of irrigant penetration minimizes transportation, zipping, ledgingminimizes transportation, zipping, ledging less irritants and toxins pushed through the foramen working length less likely to change less stress, minimizes breakageless stress, minimizes breakage

allows greater volume of irrigant penetration minimizes transportation, zipping, ledgingminimizes transportation, zipping, ledging less irritants and toxins pushed through the foramen working length less likely to change less stress, minimizes breakageless stress, minimizes breakage

Apical Control Zone

Apical Control Zone

The The ‘Apical Control Zone’‘Apical Control Zone’ is a matrix-like region created in is a matrix-like region created in the apical third of the root canal space. The zone the apical third of the root canal space. The zone demonstrates an exaggerated taper from the clinician demonstrates an exaggerated taper from the clinician defined apical constriction whether this is spatially a linear defined apical constriction whether this is spatially a linear or point determination. This enhanced taper in the apical or point determination. This enhanced taper in the apical control zone provides resistance form against the control zone provides resistance form against the condensation pressures of obturation and acts to prevent condensation pressures of obturation and acts to prevent the extrusion of the filling material during obturation.the extrusion of the filling material during obturation.

The The ‘Apical Control Zone’‘Apical Control Zone’ is a matrix-like region created in is a matrix-like region created in the apical third of the root canal space. The zone the apical third of the root canal space. The zone demonstrates an exaggerated taper from the clinician demonstrates an exaggerated taper from the clinician defined apical constriction whether this is spatially a linear defined apical constriction whether this is spatially a linear or point determination. This enhanced taper in the apical or point determination. This enhanced taper in the apical control zone provides resistance form against the control zone provides resistance form against the condensation pressures of obturation and acts to prevent condensation pressures of obturation and acts to prevent the extrusion of the filling material during obturation.the extrusion of the filling material during obturation.

Apical Control ZoneApical Control Zone

0.0 mm 20 0.25 mm 25 0.5 mm 30 0.75 mm 35 1.0 mm 40 2.0 mm 42 3.0 mm 44 4.0 mm 46

0.0 mm 20 0.25 mm 25 0.5 mm 30 0.75 mm 35 1.0 mm 40 2.0 mm 42 3.0 mm 44 4.0 mm 46

David Rosenberg

David Rosenberg

Distal Root1 mm from Apex

Distal Root1 mm from Apex

Canal not debrided and shaped Canal not debrided and shaped to the correct to the correct diameterdiameter

Canal not debrided and shaped Canal not debrided and shaped to the correct to the correct diameterdiameter

Necrotic Tissue

Necrotic Tissue

Distal Root1 mm from Apex

Distal Root1 mm from Apex

Canals not debrided and shaped Canals not debrided and shaped to the correct to the correct diameterdiameter

Canals not debrided and shaped Canals not debrided and shaped to the correct to the correct diameterdiameter

Necrotic Tissue and

Debris

Necrotic Tissue and

Debris

What does the literature say about canal diameters?

What does the literature say about canal diameters?

Median of maxillary canal diameters 1mm from apex Mx. cent. incisorMx. cent. incisor .34mm .34mm Lateral incisorLateral incisor .45mm.45mm Canine Canine .31mm.31mm Premolar Premolar .37mm.37mm MB1, MB2 (molar)MB1, MB2 (molar) .19mm.19mm DBDB .22mm.22mm PalatalPalatal .33mm.33mm

Median of maxillary canal diameters 1mm from apex Mx. cent. incisorMx. cent. incisor .34mm .34mm Lateral incisorLateral incisor .45mm.45mm Canine Canine .31mm.31mm Premolar Premolar .37mm.37mm MB1, MB2 (molar)MB1, MB2 (molar) .19mm.19mm DBDB .22mm.22mm PalatalPalatal .33mm.33mm

Wu et al 2000

What does the literature say about canal diameters?

What does the literature say about canal diameters?

Median of mandibular canal diameters 1mm from apex Md. central incisorMd. central incisor .37mm .37mm Lateral incisorLateral incisor .37mm.37mm Canine Canine .31mm.31mm Premolar Premolar .35mm.35mm MB (molar)MB (molar) .40mm.40mm MLML .38mm.38mm DistalDistal .46mm.46mm

Median of mandibular canal diameters 1mm from apex Md. central incisorMd. central incisor .37mm .37mm Lateral incisorLateral incisor .37mm.37mm Canine Canine .31mm.31mm Premolar Premolar .35mm.35mm MB (molar)MB (molar) .40mm.40mm MLML .38mm.38mm DistalDistal .46mm.46mm

Wu et al 2000

Radiographic terminus alters throughout life – cellular cementum deposition

Radiographic terminus alters throughout life – cellular cementum deposition

Apical foramenApical foramen

Radiographic Terminus – NOT!!Radiographic Terminus – NOT!!

Electric Foramenal LocatorsElectric Foramenal Locators

In 1962 Sunada determined that the In 1962 Sunada determined that the resistance between oral mucosa resistance between oral mucosa and periodontal ligament is a and periodontal ligament is a constant value 6.5 ohms (40/constant value 6.5 ohms (40/μμAmp)Amp)

In 1962 Sunada determined that the In 1962 Sunada determined that the resistance between oral mucosa resistance between oral mucosa and periodontal ligament is a and periodontal ligament is a constant value 6.5 ohms (40/constant value 6.5 ohms (40/μμAmp)Amp)

must turn unit on before attaching

probe to unit…

“might think in previous tooth” canals can be wet, but chamber must

be dry…

no shared fluid between canals instrument must be free in access

opening…

no contact with metal

must turn unit on before attaching

probe to unit…

“might think in previous tooth” canals can be wet, but chamber must

be dry…

no shared fluid between canals instrument must be free in access

opening…

no contact with metal

EAL = 0.0EAL = 0.0

Anatomic apexAnatomic apex

PDL,cementum & bone

PDL,cementum & bone

Bleeding pointBleeding point

**

Working LengthWorking Length

generic knowledge of root lengths measure radiograph –

advantage of digital images foramenal locators

USED REPEATEDLY final WL determined after

coronal debridement – lengths change with shaping

generic knowledge of root lengths measure radiograph –

advantage of digital images foramenal locators

USED REPEATEDLY final WL determined after

coronal debridement – lengths change with shaping

foramenal locators foramenal locators USED REPEATEDLYUSED REPEATEDLY

Guru ConclusionsGuru Conclusions

Several trends are increasingly evident:Several trends are increasingly evident:

most NiTi techniques are hybrid rotary file protocolsmost NiTi techniques are hybrid rotary file protocols most operators create tapered apical preparations, ranging most operators create tapered apical preparations, ranging

from .06 to .2 or more from .06 to .2 or more most use a thermolabile techniquemost use a thermolabile technique most use patency files all the timemost use patency files all the time all use foramenal locators as primary length determinantall use foramenal locators as primary length determinant not all take WL x-rays and some use paper points for not all take WL x-rays and some use paper points for

length confirmationlength confirmation presence of an ACZ is dependent on operator’s techniquepresence of an ACZ is dependent on operator’s technique

Several trends are increasingly evident:Several trends are increasingly evident:

most NiTi techniques are hybrid rotary file protocolsmost NiTi techniques are hybrid rotary file protocols most operators create tapered apical preparations, ranging most operators create tapered apical preparations, ranging

from .06 to .2 or more from .06 to .2 or more most use a thermolabile techniquemost use a thermolabile technique most use patency files all the timemost use patency files all the time all use foramenal locators as primary length determinantall use foramenal locators as primary length determinant not all take WL x-rays and some use paper points for not all take WL x-rays and some use paper points for

length confirmationlength confirmation presence of an ACZ is dependent on operator’s techniquepresence of an ACZ is dependent on operator’s technique