Tnn /prosthodontic courses

ANATOMIC CONDITIONS &
MORPHOLOGIC VARIATIONS
IN SUCCESS OF ENDODNTICS
INDIAN DENTAL ACADEMY
Leader in continuing Dental Education
www.indiandentalacademy.com

contents
• Introduction
• Anatomic components of root canal system
• Classification of root canal morphology
• General considerations
pulp chamber
orifice & coronal part of root canal
apical part of root canal
apical foramen
extra canal/s
accessory & lateral canals
buccolingual width
curved canals
age & Pathological changes
isthmus

• Special features
C-shaped canals
developmental anomalies
blunder buss canals
• Conclusion
• References

Introduction
• Reasons for failure of endodontic therapy
• Current advancements in the designing of
endodontic instruments and changes in the
procedural concepts are based in accordance
to the morphology of root canal system.
• Root canal anatomy being unchangeable,
judges and determines the fate of
instruments and instrumentation technique.

Anatomic components of root canal system

Classification of root canal morphology
According to Weine:

According to Vertucci

According to Gulabivala and coworkers

GENERAL CONSIDERATIONS
PULP CHAMBER:
• Cavity situated inside the crown portion of a tooth
containing pulp tissue.
• Locating orifices
• Floor: color, contour, periphery and its nature.
• Color & contour: dark and convex.
• Periphery of the floor: distinct and appear as groove
• Nature of the floor: 50% 0f molar possess accessory
canals in the floor.

Clinical implications:
1. Large lateral canal in the
pulp floor of a pulpally
involved molar may lead to
destruction and formation
of lesion in the furcal
bone.
2. Defective final restoration
– initiate formation of
pathological lesion in the
furca.

Orifice & coronal part of the root canal
• Careful preparation in the early phase of
instrumentation
• Generally termed ‘flaring’ & sometimes ‘widening’
or ‘enlarging’.

4 reasons for coronal preflaring:
1. Direct approach to apical 1/3rd.
2. Facilitates the passage of irrigation solution.
3. Debris & microorganisms found abundantly can be
eliminated which prevents inadvertent pushing of
these substance.
4. Spreaders and pluggers can be taken to adequate
depth which facilitates better obturation.

Hints for canal orifice location
1. know the tooth
anatomy
2. Radiographs
3. Create adequate
access
4. Use adequate
illumination
5. Use magnification
6. Use the dentinal map

7. Use an sharp endodontic
explorer
8. Use goose neck burs
9. Use long thin ultrasonic tips
for troughing

10. Use long shank burs
11. Use microopeners and small files
12. Transillumination

13. Use a dye
14. Sodium hypochlorite ‘champagne test’
15. Bleeding points

New Laws for finding pulp chamber & Canal Location
Karsner & Rankow
Relationship of the pulp
chamber to the clinical
crown:
• Law of Centrality
• Law of Concentricity
• Law of CEJ

Relationships on the
pulp chamber floor:
• Law of Symmetry 1
• Law of Symmetry 2
• Law of Color change
• Law of Orifice
Location 1
• Law of Orifice
Location 2
• Law of Orifice
Location 3

Apical part of the root canal
• Morphologically – most
complex region
• Therapeutically –
challenging zone
• Prognostically – an
important factor
• Unfortunately – most
obscure & unclear area.

Clinically significant features of the apical part:
1. Accessory canal:
• clinical significance:
canal 1mm long & 0.25mm
in diameter may harbor
80,000 streptococcus.
This morphologic feature
emphasizes the
importance of thorough
irrigation, cleaning,
shaping and filling of the
canal upto the apical
constriction.

2.Divisions:
may bifurcate or
trifurcate in the apical
third and may exist as
many foramina
3.Curvature:
clinical management –
preflaring of the
coronal part
- pre curving the files
• failure to precurve or
preflare may result in
ledging, ripping,
iatrogenic canal
formation or perforation
of the apical third.

4.Patency:
canals are almost always patent in the apical third.
clinical significance:
•knowledge of this feature is of great clinical
importance.
•Radiographic appearance of a hazy & obliterated root
canal coupled with difficulty that a clinician encounter
while tracing the orifice/s and maneuevering the
coronal part of a canal with an instrument may give a
false impression that the apical third is completely
calcified.
•This impression may not be clinically accurate; a canal
may be calcified at the orifice & coronal few mm of a
canal, but it seldom isat the apical part.

Radiographic appearances of apical third:
1. Thin (pinched) apex
2. Bulbous apex
3. Resorbed apex
4. Blunder buss apex

Apical foramen
Location & shape – great
endodontic significance.
Location:
Detecting the location:
1. Radiographs
2. Direction & location of
periapical lesion
3. Electronic apex locator
Clinical significance:
Overestimation: violation of
apical constriction
Underestimation: canal space
uncleaned & unfilled

Shape:
• Usually round or oval
Current description:
1. Round
2. Oval
3. Long oval
4. flattened

Variations in apical
constriction:
1.Traditional single
2.Tapering constriction
3.Multiconstricted
4.Parallel constriction

• It acts as a natural stop – advantage
• Disadvantage – debris or dentinal mud get accumulated,
instrumentation become difficult and leads to mishaps
“Maintaining the original position and shape of the apical constriction are two main
objectives of root canal preparation procedure.”
Recommended steps to preserve the apical foramen:
1. Working length – measured correctly.
2. Canal patency – maintained through recapitulation.
3. Irrigation.
4. Avoid using H-file instrument before determining the working
length.

Extra canals
• The word ‘extra canal’
• Failure to locate and treat an extra canal is one of
the common causes for failures of root canal
treatment.
• How to detect
1. Knowledge
2. Enthusiasm
3. Clinical
4. Radiograph

SLOB rule

Extra dark line

Outline of the root

Fast break

Accessory & lateral canals
•The principal or main root canal in a root may
communicate with the surrounding periodontium at any
level through lateral & accessory canal.
•Lateral canals – perpendicular to the principal canal.
•Accessory canal – mostly found in apical third.

1. Difficult to clean.
2. Their presence in the floor of the pulp chamber.
3. Causes post pulpectomy pain.
4. Multiple accessory canals.
Detection of lateral canals:
• Thickening of pdl.
• Development of frank lesion in the lateral waall of
the root.
• Post obturation radiograph.

Buccolingual width
Effective endodontic treatment, the root canal of a
tooth is required to be understood in its wholeness
i.e.., 3 dimensionally

Curved canals
How to assess the canal
curvature in the
radiograph:
1. Increased radiopacity
2. “Bull’s-eye” or “target”
appearence

Root canal curvature measurement techniques
1. Weine angle technique
2. Long axis technique
3. Schneider angle
technique
4. Canal access angle
technique
“Failure to note this morphological
feature during endodontic
instrumentation procedure is a
common cause for failure of
root canal treatment”.

Age & pathological changes
Secondary/tertiary dentin:
• Mostly occurs on the pulpal
floor
• Along with thickening &
elevation of pulpal floor, the
shape, size and position of the
orifice, and also the width of
cervical part of the root canal
changes.
• It is interesting & also
important to note that
dimension of the canal in the
apical third does not decrease
in size.

Type of calcification:
1. Concentric or linear
2. Irregular

Pulpal stones

Apex, Apical foramen & Age

Isthmus:
kim et al:

SPECIAL FEATURES:
C-SHAPED CANALS:
• Thin strip of groove
• True c- shaped canal
• False c- shaped canal
• Characteristic feature
is that their propensity
to occur among Asians
and in lower second
molar.

• Difficult to diagnose
the c-shape
radiographically
• Difficult to prepare the
canals
• Persistent hemorrhage
following initial pulp
extripation
• Interappointment pain
• No specific obturation
technique.

DEVELOPMENTAL ANOMALIES
Dens invaginatus:

Lingual radicular groove
• Gingivo palatal
groove
• Commonly seen in
maxillary lateral
incisors
• 2.5%
• Length & depth

Blunder buss canal
• Canals are thin & fragile
• Proper condensation is impossible due to
absence of barrier.
• Management depends upon vitality.

References:References:
• Pathways of the pulp; 9th
edition; Cohen
• Pathways of the pulp; 8th
edition; Cohen
• Advanced endodntics for clinicians; Jacob G.Daniel
• Endodnotic topics 2005; 10; 3-29
• Practical clinical endodontics: Churchchill
• Endodontic therapy;Weine; 6th
edition
• Endodontic practice; Grossman;11th
edition
• JOE; 2004; vol 30; N0 1; 5-16.
• JOE; 2005; No 11; Vol 31; 796-798.
• Endodontics; Stock & Gluabivala
• Ingle 5th
edition.

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