This document provides an overview of the internal morphology of permanent teeth. It discusses root canal anatomy terminology and classifications. Details are given on the root canal morphology of each tooth in the maxilla and mandible, including number of roots and canals, root and canal shapes, and anatomical variations. The aim is to provide knowledge of root canal architecture to help with effective debridement, determination of working length, and obturation.

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Internal Morphology Of
Permanent Teeth
Seminar :1
Module :1
By: Dr. Arbiya Anjum S

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CONTENTS
o INTRODUCTION
o TERMINOLOGIES
o CLASSIFICATION
o MAXILLARY TEETH ANATOMY
o MANDIBULAR TEETH ANATOMY
o CONCLUSION
o REFERENCES

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INTRODUCTION
• “Of all the phases of anatomic study in the human system,
one of the most complex is the pulp cavity morphology” –
M.T.BARRETT
The knowledge of root canal architecture will help us in
• Effective debridement
• To know the apical termination of instrumentation
• 3d obturation of canal

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ROOT CANAL ANATOMY
Root canal system It is the space
within the tooth that contains
pulp tissue.
Roof of pulp chamber - Dentin covering the pulp
chamber occlusally or incisally.
Pulp horn -Accentuation of the roof of the pulp
chamber directly under a cusp or developmental
lobe.
Floor of pulp chamber- Runs parallel to the roof
and consists of dentin bounding the pulp
chamber near the cervical area of the tooth.
Canal orifices- Openings in the floor of pulp
chamber leading in to root canals

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A = Root apex
B = Apical constriction
C = Root canal
D = Cementum
E = Dentine
F = Apical foramen
Major apical foramen:
• It is the exit of the root canal onto the external root surface, located
within 3 mm of the root apex.
Minor apical foramen/Apical constriction:
• Apical part of the root canal with the narrowest diameter.
• 0.5–1 mm from the major apical foramen (Vertucci 2005).
• Often used as the reference point of apical termination of canal
instrumentation and filling procedures.

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• Space between major and minor apical diameter - FUNNEL
SHAPED, HYPERBOLIC or having the shape of a MORNING GLORY
THE CEMENTODENTINAL JUNCTION –
o The region where the dentin and cementum are united.
oCDJ does not always coincide with the apical constriction.
o The location of the CDJ ranges from 0.5 to 3.0 mm short of the
anatomic apex.

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LATERAL AND ACCESSORY
CANALS

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WEINE’S
CLASSIFICATION
Vertucci’s
classification

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Int Endod J. 2017 Aug;50(8):761-770. doi: 10.1111/iej.12685. Epub 2016 Oct 17.
A new system for classifying root and root canal morphology.
Ahmed HMA1, Versiani MA2, De-Deus G3, Dummer PMH4.

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ISTHMUS
An isthmus is a narrow, ribbon-shaped communication
between two root canals that contains pulp or pulpally
derived tissue.

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INDIVIDUAL ROOT CANAL
ANATOMY

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Root canal
morphology
shows presence
of one canal per
root except the
lower incisors ,
upper
premolars, mb
root of upper 1st
molar, mesial
root of lower
molars (2 root
canals).

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MAXILLARY CENTRAL INCISOR
Average Tooth Length- 22.8mm
Root chamber-
• Location - center of the crown equidistant from
the dentinal walls.
• Broad and ovoid - mesiodistally
• Broadest -incisally
• 3 pulp horns(mamelons)
Root and root canal- 1
.
• Centrally located, Conical in shape
• In c.s: Ovoid mesiodistally- cervical 3rd
Ovoid to round – middle 3rd
Round-apical 3rd

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MAXILLARY LATERAL INCISOR
Average Tooth Length-22.5mm
Root chamber-
• same as central incisor but smaller
• 2 pulp horns (mamellons)
Root and root canal- 1
• Conical, Finer diameter than central
incisor
• In c.s,
• Ovoid labiopalatally- cervical 3rd
• Ovoid -middle 3rd
• Round -apical 3rd

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MAXILLARY CANINE
Average Tooth Length-26mm
Root chamber-
labiopalatally - triangular in shape with
apex towards the single cusp and base in
cervical 3rd of the crown.
Mesiodistally – narrow as a flame
One pulp horn (one cusp)
Root and root canal- 1
Wider labiopalatally than mesiodistally &
on reaching middle 3rd tapers gradually at
apical constriction.

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MAXILLARY FIRST PREMOLAR
Average Tooth Length-21.5mm
Root chamber-
• narrow mesiodistally
• pulp horn under each cusp (buccal
higher level)
• 2 orifices (B&P)
Root and root canal- 2
• 2 roots – 54.6%(21.9% separated &
32.7% partially fused)

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The roots of upper first premolars are very
delicate and may curve quite sharply buccally,
palatally, mesially or distally, so instrumentation
needs to be carried out with great care.
Cross-sections taken at
different levels in a maxillary
first premolar showing the
division of the buccal canal.
Examples of upper
premolars with three
roots.

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MAXILLARY SECOND PREMOLAR
Average Tooth Length- 21.6mm
Root chamber-
narrow mesiodistally wider buccopalatally
2 pulp horns (B&P)
Root and root canal-
90.3% 1 root , 2% 2 well developed ,
7.7% partially fused 2 roots.
.

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MAXILLARY FIRST MOLAR
Average Tooth Length- 21.3mm
Root chamber- largest in the arch.
Roof– rhomboidal , pulp horns –mb,db,mp & dp.
Root and root canal- 3
Roots
P-largest(22mm), flat ribbon like
DB-(21mm) small, narrow
MB –(21mm) narrowest
Orifice
P-largest , round
MB-under the mesiobuccal cusp, broad buccolingually
DB- distal and to palatal mesiobucal orifice, ovoid

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Locating MB2 orifice – • Difficult as its buried under
dentine bridge formed as a result of aging

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MAXILLARY SECOND MOLAR
Average Tooth Length- 21.7mm
Root chamber-
Similar to maxillary 1st molar, except narrower
mesiodistally
Root and root canal- 3
MB Root
• Broad buccolingually
• 1 or 2 canals
DB Root
• Rounded / ovoid, single canal
• Orifice appears on same line joining mesiobuccal
& palatal canals
Palatal root
• Broad mesiodistally
• Ovoid, Single canal

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MAXILLARY THIRD MOLAR
• Average Tooth Length- 17.1mm
• Root chamber- similar to second molar
with 3 orifices
• It may also have oddly shaped chamber
with 4/5 rc orifices or conical shape
with 1 orifice
• Root and root canal-
• 3 well developed roots closely placed
• Fused roots or conical or 4/5
independent
• Root – curved , straight dilacerated
• C shaped canal may be seen

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MANDIBULAR CENTRAL INCISOR
Average Tooth Length- 20.8mm
Root chamber-
• smallest tooth in the arch
• Small & flat – mesiodistally
• Wide labiolingually
• Tapers incisally
Root and root canal- 1
• Straight - 60%

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MANDIBULAR LATERAL INCISOR
Average Tooth Length- 22.6mm
Root chamber-
Similar to central incisor but slightly larger
dimension
• Small & flat – mesiodistally
• Wide labiolingually
• Tapers incisally
Root and root canal-1
• Straight - 60%

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MANDIBULAR CANINE
Average Tooth Length- 25 mm
Root chamber-
Resembles maxillary canine but smaller
• Narrow mesiodistally
• One pulp horn
Root and root canal-1
• Straight - 68%

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Lower canines may occasionally be found with two separate roots.

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MANDIBULAR FIRST PREMOLAR
Average Tooth Length-21.9mm
Root chamber-
Narrow mesiodistally, wider buccopalatally
• Pulp horn under each cusp, buccal pulp horn more
prominent
• 2 canal orifices (lies deep in coronal third of root below
cervical line)
Root and root canal- 1 (70%)
• 1 canal bifurcates into 2 and ends in 2 foramina – 24%
• 2 -2– 1.5%
• 1-2-1 – 4%
• 3-3– 0.5%

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MANDIBULAR SECOND PREMOLAR
Average Tooth Length-22.3mm
Root chamber-
• Narrow mesiodistally
• Wider buccolingually
• Prominent Lingual pulp horn
Root and root canal-
• Single canal – 97.5%
• Some roots bifurcates exiting in 2 foraminas – 2.5%

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A lower second premolar with a severe distal curve at the apex.

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MANDIBULAR FIRST MOLAR
Average Tooth Length-21.9mm
Root chamber-
• 4 pulp horns : MB, ML, DB, DL
• 3 distinct orifices : MB, ML & distal
• Roof – Rectangular in shape
Root and root canal- Normally 2 m
and 1 d canal
.

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Lower first molars may occasionally be found with two separate distal roots.

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MANDIBULAR SECOND MOLAR
Average Tooth Length-21.4mm
Root chamber- Similar to 1st molar but
smaller in size
Root and root canal-
• Mesial root – higher incidence of 1 canal – 14%
• Higher incidence of root fusion
• C-shaped canals are frequent Mandibular 2nd
Molar
• In a mandibular second molar with two canals,
both orifices are in the mesiodistal midline.

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MANDIBULAR THIRD MOLAR
• Average Tooth Length-18.5mm
• Root chamber-
• Similar to 1st & 2nd molar but smaller in
size.
• Large
• c-shaped canal
• Root and root canal-
• canal 2 root and 2 canal
• Ocasionally, 1 root & canal or3 roots& 3
canals

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The developmental anatomy of lower third molars may be quite bizarre.

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CONCLUSION
• Root canal system is extraordinarily complex with
numerous intricacies , including accessory canals and
isthami.
• Therefore ,The endodontist should have the basic
knowledge of root canal system while appreciating the
complexity and its variations for the successful treatment
outcome.

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REFERENCES
• GROSSMAN -13TH EDITION
• COHEN- 9TH EDITION
• INGLE’S – 6TH EDITION
• MORPHOLOGY OF ROOT CANAL SYSTEM BRITISH
DENTAL JOURANL VOLUME 197.
• Int Endod J. 2017 Aug;50(8):761-770 A new
system for classifying root and root canal
morphology.

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