Anatomy and Clinical Significance of the Root Apex

11/13/2018 1
Don’t just follow your
dreams
CHASE THEM . . . .
Anatomy of Root Apex

Presented by: Dr Abhisek Guria
Dept. of Conservative Dentistry & Endodontics
SHDCH , Hassan
Date of Presentation : 20/06/2018

11/13/2018 3Anatomy of Root Apex

Contents
• Introduction
• Development of root apex
• Accessory canal formation
• Root length & apical closure
• Apical root anatomy
• Apical constriction
• Topography of apical constriction
• Clinical significance
• CDJ
• Location & diameter

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• Apical foramen
• Exit ofAF
• Number of AF
• Size of AF
• Variations in morphology of apical third of the
root & its significance in endodontics
1. Accessory canals
2. Areas of resorption
3. Repaired resorption
4. Pulp stones – attached, embedded & free
5. Varied amount of irregular secondary dentin

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• Radiographic Assessment Of Apical Third
• Types Of Root Apex
• Thin Pinched Apex
• Bulbous Apex
• Resorbed Apex
• Blunderbuss Apex
• Histology OfApical Dentin And Pulp
• Termination Point For Root Canal Procedures
• Challenges Faced Due To Apical Third Anatomy During
Endodontic Procedures

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• Isthmus
• Classification
• Clinical Significance
• Working Width
• Shape & Size Of The Apical Preparation
• Preflaring
• Final Width Of Canal
• Root End Resection
• Extent Of Apical Resection
• Bevel Angle

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• Procedural errors seen atthe rootapex
• Ledging
• Apical transportation
• Perforation
• Zipping
• Loss of patency
• Conclusion
• References

Introduction
Morphologically - most complex region
Therapeutically - most challenging
Prognostically - most important
Radiographically - most obscure unclear area

Mountain pass theory
• Kronfeld, 1939
• Rationale for non surgical
endodontic treatment
• Zone A: bacteria – invaders
AF- mountain pass
• Zone B: granulomatous tissue at
periapex- mobilized army
• Zone C: complete elimination of
invaders

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• Begins after enamel & dentin formation reached future CEJ

HERS
• Molds the shape of root
• Initiates radicular dentin formation

HERS takes a bend horizontally
towards dental papilla to form
Epithelial Diaphragm
Ectomesenchymal cell start
proliferating
Root dentin formation begins
Epithelial Diaphragm will remain in
place while crown and supporting
structure move occlusally ( Orban)

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Epithelial Diaphragm &
Apical foramen

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Disintegration of HERS
Cells of dental sac comes in contact of dentin
Deposition of cementum
Odontoblast
Predentin
Root dentin
Dentino cemental
Junction
Pulp
Cementoid
Cementum
Cementoblast
Cementocyte
Dental sac
Dental sac cell
Becoming a
Cementoblast
Formation of
Periodontal ligament
Epithelial rests
Of Malassez
Developing bone

• Cellular cementum at apical third
• Continues throughout life
• Maintains length of root
• Constricts apical foramen
• Deviates apical foramen
• Apical cementum is thicker than coronal third

ACCESSORY CANAL FORMATION
• Source of collateral circulation for pulp
• More prevalent in apical third
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• Defect in the epithelial root sheath
• Failure in the induction of
dentinogenesis
• The presence of small blood vessels
produce a gap -
accessory canal

APICAL CLOSURE
• Plays important role in repair of dental pulp
following Endodontic Therapy
• Early in females
• Apical closure of Maxillary posterior is later than
mandibular teeth
(Moorees et al 1963)

Three anatomic & Histologic landmarks
Apical constriction
CDJ
Apical foramen

Apical constriction
Narrowest diameter of the root canal with the smallest
diameter of blood supply & preparation to this point results
in a small wound site & optimal healing condition.
(Ricucci & Langeland)
• usually occurs within the dentin
• Just prior to initial layer of cementum – called ‘’MINOR
DIAMETER’’ ( Kuttler )

Some called as
‘’ Physiologic foramen’’
AC which is generally 0.5–1.5 mm
inside the AF
Increase distance in older individual
is because of cementum deposition

Mean perpendicular distance from the
root apex to the apical constriction
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Mesiodistal (mm) Labiolingual (mm)
0.370 0.428
0.307 0.369
0.313 0.375
Teeth
Vertical (mm)
Central incisor
0.863
Lateral incisor
0.825
Canine
1.010
Mizutani T, Ohno N, Nakamura H.

• Briseno Marroquin et al did a study on Egyption
population and concluded that
† Shape – oval (70%)
High percentage of 2 physiologic foramina in
† Mesial root of mandibular ( 87%)
† Mesio-buccal root of maxillary first molar (71%)
Morphology of the Physiological Foramen:I. Maxillary and Mandibular
Molars VOL. 30, NO.5,MAY2004

ROOT CANAL MORPHOLOGY
11/13/2018Anatomy of Root Apex 28

GULABIVALA Classification

Topography of apical
constriction
( Dummer )

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Radiograph (A) and histologic section (B) of ideal apical constriction on
tooth #7.

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Radiograph (A) and histologic section (B) of palatal root of tooth
#15 with no apical constriction

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Radiograph (A) and histologic section (B) of mesial root of
tooth #19 with apical foramen well short of radiographic apex.

Clinical significance
• Canal preparation & obturation should terminate at minor
diameter
• Provide a bottle neck area during obturation – rapid
development of Apical dentin matrix
• Retaining filling material & sealers
within the canal
• Painfree treatment can be done
without damaging periapical tissue

CDJ
• It is the point in canal where cementum meets dentin
• Where pulp tissue end and Pdl tissue begins
• Histological landmark, cannot be located clinically or
radiographically

Location & diameter
• Ponce & Vilar Fernandez et al evaluated histologic
section of maxillary ant. To determine the location &
diameter
 Extension differed considerably on opp. Canal wall
 Extend till same level in 5%
 Greatest extension on the concave side of canal
curvature
 CDJ & AC are generally not coinciding with the same
area

• Diameter of canal at CDJ was highly
irregular
 Max. central incisor – 353 µm
 Lateral incisor – 292 µm
 Canines – 298 µm
 Located 0.5 - 3 mm short of the anatomic apex
(Tamse A,KaffeI, Fishel D, 1980)

 Theoretically, the CDJ is the appropriate apical limit
for root canal treatment
 As at this point the area of contact between the
periradicular tissues and root canal filling material is
likely to be minimal
(Palmer et al. 1971, Seltzer 1988, Katz et al. 1991, Ricucci &
Langeland 1998)

• ‘’ theoretically ‘’ – because it is a histologic
landmark
• Clinically impossible to identify
• Therefore, it cannot be an ideal landmark to
use clinically as the end-point for root canal
preparation and filling.

Apical foramen (AF)
Circumference or rounded edge, like a funnel
or crater, that differentiates the termination
of the cemental canal from the exterior
surface of the root. ( Cohen)

Apical foramen (AF)
• From AC or Minor Diameter the canal
widens as it approaches the AF or the
Major Diameter
• Shape between AC & AF has been
described as
 Funnel shaped
 Hyperbolic
 Morning glory

Mean distance
b/w major & minor
diameter
0.5 mm- young
person
0.67 – older
individual
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Age (yrs)
• 18- 25
• > 55
Diameter (µ)
• 502
• 681 Kuttler

EXIT OF AF
• Doesn’t normally exit at the anatomic apex but
is offset 0.3 – 0.5 mm
• Both root apex & AF of central incisors & canine
showed distolabial displacement
• Lateral incisor – distolingual displacement
( Mizutani et al)

• AF situated directly at the apex
in maxillary centrals, laterals, cuspids, first
premolars and mandibular second premolars
• AF coincide less frequently
In the maxillary molars and all the
mandibular teeth with the exception of the
2nd PM.
GREEN(1955 1956 1960)

Number of AF
• Morfis et al studied apices of 213 permanent teeth
with SEM & determined :
• > 1 AF was observed in all teeth except for distal
root of mand. Molars & palatal root of max. molars
• Highest % of multiple AF was observed in
 Mesial root of mand molars - 50%
 Maxillary premolars – 48.3%
 Mesial root of max molars – 41.7 %

Size of AF
• All groups of teeth exhibited at least 1
accessory foramina
• Max. premolars have largest no & size of
accessory foramen (53.4um) with most
complicated apical makeup
• Followed by mand. premolars

Size of main apical
foramina
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Teeth Mean values (u)
Maxillary incisors 289.4
Mandibular incisors 262.5
Maxillary premolars 210.0
Mandibular premolars 268.2
Maxillary molars
Palatal 298.0
Mesiobuccal 235.05
Distobuccal 232.20
Mandibular molar
Mesial 257.5
Distal 392.0
*Results published previously in: Morfis A, Sylaras SN, Georgopoulou M, Kernani M, Prountzos F.Study of
the apices of human permanent teeth with the use of a scanning electron microscope. Oral Surg Oral
Med Oral Pathol Oral Radiol Endod 1994: 77(2):172–176.

• Inadequate knowledge and mismanagement of
apical foramen may affect long and short
term success of RCT
• May change due to functional influences-
occlusal pressure, mesial drift

Variations in morphology of apical third
of the root & its significance i
• Major et al found tremendous variations in
morphology of apical region of root
1. Accessory canals
4. Pulp stones

1. Accessory canals
• Accessory canal branches off from
the main root canal in the apical region
• Lateral canal is located at right angles to main root
canal
• Furcation canal seen at furcation
• Formed when
1. the root sheath disintergrates when dentin is
elaborated
2. lack of dentin formation around a blood vessel

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• Tissue-fibroblasts, collagen
fibres , nerves, macrophages
(resemble CT of PDL rather
than pulp)
Lateral canals are more
common in bifurcation
and trifurcation
region of molars

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 accesory canals have a
mean diameter of 6- 60 µm
(HESS et al, 1963)
 Accessory canals form
apical deltas in the root
apex
 In distal root of
mandibular molars and
palatal of maxillary molars
–these canals fan out
towards the apex in a
canoe –shaped
arrangement

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Shows 3 distinct patterns in the mandibular first molars.
A. In 13% a single furcation canal extends from the pulp chamber
to the intraradicular region.
B. In 23% lateral canals extends from the coronal third
(80% extend from the distal root canal).
C. About 10% have both lateral and furcation canals.

Apical delta
•Y shaped branching of root
canal near apex.
•Difficult to instrument &
obturate
•Mostly not visible in radiograph

• No of accessory canals – not a significant
factor in success of endodontic therapy
• following endodontic therapy in teeth with vital pulps they
become obliterated by the deposition of cementum
• In non-vital teeth, inflammatory tissue will get resorbed
and replaced with uninflammed connective tissue.
(Hess 1983)

• They are avenues for interchange of
metabolic and breakdown products
between pulp and periodontal tissue
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If present in the floor of pulp
chamber they transmit toxins and
irritants from pulp
Establish a lesion in furcation
which may appear radiographically
as periodontal disease

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o They are usually not detected in
intraoral radiographs
o They may become noticeable
subsequent to the necrotization of
the main canal
o Thickening of the PDL or development
of a frank lesion in the lateral wall of
the root
o Become apparent in the post –obturation x-ray where
radio-opaque material is seen extending to surface of
root

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Presence of these
canals emphasize the
need for employing
effective irrigation
solution and technique
and also three
dimensional filling of
root canal

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• When the pulp is extirpated from
a vital tooth ,pulp stump may
remain in these canals –causing
post- pulpectomy pain and also
pain felt when sealer is pushed
into these canals

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• May harbour micro
organisms and
continue to irritate
periapex
• Lesion may grow
despite radiographic
evidence of proper
filling of principal
canal.
• Require periapical
surgery

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Although the
incidence of
occurrence of these
canals is high – the
percentage of failures
due to unfilled canals
is small in clinical
practice
because of the
biological hard tissue
closure(cementum)
subsequent to the
elimination of chronic
inflammation and
irritants from main
canal

• Shallow resorption of dentin in apical
portion
• Resorption of cementum and dentin
occurs on the body of the root also at
the periapical region
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Mainly due to
1. Orthodontic tooth movement
2. Inflamation of apical pulp &
periodontal tissue

• Resorption widens apical foramen
• As inflammation subsides , repair of resorbed
region occurs by deposition of secondary
cementum
• As a result position of AF shifts laterally

3. Pulp stones / denticles
• Formed around the foci of mineralizing pulp
tissue components
• Can be free, attached or embedded
• In the apical third 15 % of the teeth shows
denticles

Apical calcification
• In chronic inflammation & aging, calcification
of the canal occurs
• In some cases only apical 1/3rd is calcified-
obturation become difficult
• Effort should be made to negotiate with EDTA
& thin files

4. Varied amounts of irregular
secondary dentin
• Deposited continuously by the radicular pulp
tissue
• Twards the apex, the dentinal tubules appear
to blend with cementum canaliculi
• Continuous deposition will reduce the size of
AF, but complete closure doesn’t occure as
long as vital pulp present

Canal curvature
• Apical third of roots are complex also in
curvature
• Usually show a distal curvature
• A buccal or lingual curvature may not
be discernible in radiograph

Clinical management

Learn everything you can, anytime you can,
from anyone you can.
There will always come a time when you
will be grateful you did.
- sarah caldwell

Presented by: Dr Abhisek Guria
Dept. of Conservative Dentistry & Endodontics
SHDCH , Hassan
Date of Presentation : 22/06/2018

11/13/2018 72
Edward Maynard (1813- 1891)
pioneer of endodontic hand instruments

Contents
• Introduction
• Development of root apex
• Accessory canal formation
• Root length & apical closure
• Apical root anatomy
• Apical constriction
• Topography of apical constriction
• CDJ
• Location & diameter

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• Apical foramen
• Exit ofAF
• Number of AF
• Size of AF
• Variations in morphology of apical third of the
root & its significance in endodontics
1. Accessory canals
4. Pulp stones – attached, embedded & free

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• Root canal morphology
• Measurement of canal curvature
• Radiographic Assessment Of Apical Third
• Types Of Root Apex
• Thin Pinched Apex
• Bulbous Apex
• Resorbed Apex
• Blunderbuss Apex
• Histology OfApical Dentin And Pulp
• Termination Point For Root Canal Procedures
• Challenges Faced Due To Apical Third Anatomy During
Endodontic Procedures

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• Isthmus
• Classification
• Clinical Significance
• Working Width
• Shape & Size Of The Apical Preparation
• Preflaring
• Final Width Of Canal
• Root End Resection
• Extent Of Apical Resection
• Bevel Angle

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• Procedural errors seen atthe rootapex
• Ledging
• Apical transportation
• Perforation
• Zipping
• Loss of patency
• Conclusion
• References

ROOT CANAL MORPHOLOGY

GULABIVALA Classification

Schneider’s method
•Mild < 5
•Moderate 10 -20
•Severe > 20
11/13/2018 82
Journal of Restorative Dentistry / Vol - 3 /
Issue - 3 / Sep-Dec 2015 • 59

Weine’s method
11/13/2018 83
Journal of Restorative Dentistry / Vol
- 3 / Issue - 3 / Sep-Dec 2015 • 59
• angle is measured at
the point of
intersection between
the two lines

Lutein method
• Modification of Schneider’s
method
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Issue - 3 / Sep-Dec 2015 • 59

Cunningham’s and Senia’s method
• focuses on multiple root
curvatures, that is, S-shaped
canals
• angle is measured separately
at the coronal and apical ends
• Angle X – AB & BC
• Angle Y – BC & CD
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Issue - 3 / Sep-Dec 2015 • 59

Danger zone & Safe zone

Radiographic assessment of apical
third
• Root canal that descends from the pulpal floor &
suddenly stops in the apical region
• To confirm, a 2nd radiograph exposed from mesial
/ distal angulation
• Shows vertical lines indicating peripheries of
additional root surfaces

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Dividing into
two
• If canal shadow abruptly stops in the
middle third
• diameter suddenly narrows down
• common in mand. Premolars
Lateral
radiolucency
• possibility of lateral canal/accessory
canal / Pdl lesion

• Radiolucent line running along the diagnostic
instrument whose long axis is not in relation to the
instruments – additional canal

CT

Types of root apex
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THIN PINCHED
APEX
proper care required
during instumentation
Over enlargement may
lead to perforation

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BULBOUS APEX
 usually due to
hypercementosis
 proper care required
during length
determination
 Apical constriction is
significantly shorter
from radiographic apex

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RESORBED APEX
caused due to advanced
inflammation at the periapex
resorption of cementum and
dentin and widening of apical
foramen
WL determination ,preparation
and condensation of guttapercha
is difficult-
Preparation should stop 1-2mm
short of radiographic apex

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newly erupted tooth showing
open apex
therapy
BLUNDERBUSS APEX
An incompletely formed
root having a wide canal
pulp may get necrosed due
to caries or trauma and
may require root canal
therapy
standard
instrumentation and
obturation techniques
are not favorable

HISTOLOGY OFAPICAL
DENTIN AND PULP

APICAL PULP TISSUE

APICAL DENTIN

TERMINATION POINT FOR ROOT
CANAL PROCEDURES
• Controversial
• Clinical determination of apical morphology is
difficult
• Existence of apical constriction is more
conceptual than real
• Traditional single apical constriction present in
less than half the time when apical root
resorption & periapical pathosis is factor
(Dummer et al )

Weines recommendation

Wu et al
• It is difficult to locate AC or AF clinically, so radiographic
apex is more reliable point
• For vital teeth point of termination = 2-3mm short of apex
• Apical pulp stem prevents extrusion of irritating material
to periapex
• For necrotic pulp 2 mm short of apex
• Shorter than 2mm decline success rate by 20%
• In retreatment case 1-2 mm short of apex

• Most favorable prognosis – Apical constriction
• Worst prognosis – beyond AC
• Sealer or GP in periapex, lateral canals always
caused severe inflammatory reaction
(Langeland & Ricucci )
• Lim & Stock stated that 0.3mm of dentin
approx. is the minimal canal wall thickness that
should remain after prep in order to provide
sufficient resistance to obturation forces

Challenges faced due to apical third
anatomy during endodontic procedures
• The initial file chosen for exploring the canal anatomy &
for binding in canal is used as measure of apical
diameter
• This does not accurately gauge the size of oval shaped
canal
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Mandibular first premolar with three separate roots trifurcating at
midroot. B, Radiograph of three views.

WU et al
attempted to
gauge the size of
the oval shaped
root canal
75% cases initial
file contacted
only one side of
apical canal wall
25% failed to
contact any wall
In 90% the initial
diameter of the
instruments were
smaller than the
short diameter of
canal

In order to
counter this
problem,
Contreras et al
suggested
Coronal flaring
before canal
exploration –
removes interface
& increases the
initial apical file
size
This is advantage
of crown down
technique

ISTHMUS
• It is a narrow ribbon shaped
communication b/w 2 root
canals that contains pulp or
pulpally derived tissue
• They can act as bacterial
reservoir
• They must be found,
prepared & filled
• Any root with 2 or more
canals may have an isthmus

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• A complete or partial isthmus was found at 4mm
level (100%)
• In another study, partial isthmus was found more
often than complete isthmi
• Identification & treatment of isthmus are vital in
success of surgical procedures
Evangelos et al Braz Dent J (2010) 21 (5): 428-431

Classification ( Kim et al )

Conventional
mechanical
cleaning & shaping
cant physically
debride this area
Only way to clean
is thorough use of
chemical irrigants
such as NaOCL
Ultrasonics & their
associated tips can
be used in addition

In microsurgical endodontic therapy ,
clinicians are able to visualize the resected
root surface & identify the isthmus,
Preparing it with US tips & fill the root end
with acceptable materials
This reduced the failure rate of endodontic
surgery

working width
Objective of RCT – minimize no of microbes &
pathologic debris

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Thorough instrumentation of apical region
It was discussed as a critical step as early as 1931 by
Groove
Simon later recognized the apical area as the critical
zone for instrumentation.
Other authors - last few millimeters that approach the
apical foramen are critical in the instrumentation process.

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116
Difficult to investigate horizontal dimension as it varies
greatly at each vertical level
“forgotten dimension”
preparing each canal to a specific apical diameter as per its
initial apical size may better equip the clinician to provide a
more predictable canal preparation.
Horizontal dimension of RC system more complicated
than vertical

SHAPE
• Kuttler (1955) & Mizutani et al (1992)
oval, long oval, ribbon shaped or round
• Wu et al (2000) –
• 25% of AC had long oval shape
• Apical construction is not uniformly round, oval or
irregular

Size of the apical preparation:
Determine the pre-
operative canal diameter
by passing consecutively
larger instruments to the
WL until one binds
The first size that binds
at the WL is called the
initial apical file (IAF)

Preflaring
•Studies have reported that initial flaring before
determining the apical size may give a more
accurate measurement of the apex
• Apical diameter proved to be at least one file size
bigger once preflaring was done.
• Tan BT, Messer HH. The effect of instrument type and preflaring on apical file
size determination. Int Endod J 2002;35:752– 8.

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• The apical size to be two file sizes bigger after
preflaring with Gates-Glidden drills.
• The instrument used for preflaring played
a major role in determining the anatomical
diameter at the WL
Contreras MA, Zinman EH, Kaplan SK. Comparison of the first file that fits at the apex,
before and after early flaring. J Endod 2001;27:113– 6.
Pecora JD, Capelli A, Guerisoli DM, Spano JC, Estrela C. Influence of cervical
preflaring on apical file size determination. Int Endod J 2005

 The classic test for determining correct width
finding of clean, white dentin shavings on the
flutes of the reamers and files.
 But, does not necessarily indicate thorough
removal of tissue, debris, and affected dentin

• Many canals are oval or ribbon shaped in cross section.
• Clean, white dentin shavings are attainable from walls
close to each other, but the far walls may be completely
untouched while this sign is obtained

 Earlier research has shown that canals needed
to be enlarged to at least #35 file for
adequate irrigation to reach the apical third
•Salzgeber RM, Brilliant JD. An in vivo evaluation of the
penetration of an irrigating solution in root canals. J Endod
1977

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 a #25 file was as efficient as a #40 file for
reducing residual microorganisms.
 Yared GM, Dagher FE. Influence of apical enlargement on bacterial infection during
treatment of apical periodontitis. J Endod 1994
 Buchanan (2001) has advocated minimal apical
preparation (e.g. #20 or #25) based on his clinical
opinions.
• He proposed that enlarging the canal size would
cause apical transportation or zips.
• These techniques focus more on minimal apical
preparation for the prevention of iatrogenic
errors

 A 4-6 year clinical study on endodontic
outcomes favored smaller preparation
sizes with tapered shapes to larger
shapes.
 90% and 80% success rate respectively
 Treatment outcomes in Endodontics: the
Toronto Study. Phase I and II. Friedman
et al Journal of Endodontics 2004; 30:9

 An apical preparation size 20 would be
inferior to size 30 and 40 regarding canal
debridement but a larger taper (0.10) may
potentially compensate for smaller sizes.
 Baumgartner et al. influence of instrument size on
root canal debridement Journal of Endodontics
2004;30:110

 based on microbiological assays
found that apical preparation to size
30 is required to effectively clean
root canals
 Mickel AK, Chogle S, Liddle J. The role of apical size
determination and enlargement in the reduction of intracanal
bacteria. Journal of Endodontics 2007; 33:21

Large, small or Adequate ?

Reduction of intracanal bacteria using NiTi
rotary instruments & various medications

Root canal irrigants

Extent of apical resection
• 3mm apical resection –to eliminate most of
lateral canals and apical deltas

Bevel angle
• Earlier 45 degree bevel
angle placed to bring
apical foramen labially
• At present 0-10 degree
benefit of microsurgical
procedures

Advantages
 Minimizes removal
of excess buccal
cortical plate
 Exposes fewer
dentinal tubules
thus preventing
excess leakage and
contamination

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• Leakage through dentinal tubules originating at the beveled
root surface.
A. Reverse filling does not extend coronally to the height of
the bevel.
B. Reverse filling extends coronally to the height of the bevel,
blocking fluid penetration (arrows) into the root canal
space.

Case report
• A, clinical photograph of a 34-year-old man with swelling in
the buccal furcation area of his mandibular right first molar,
tooth #30.
• He gives a history of previous root canal treatment with silver
cones that required retreatment
• B, preoperativeradiograph.

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• C and D, After root resection, inspection of the root and root
tip is important. Note the accessory canals associated with the
root tip.
• E, clinical photograph taken after root end resection and
filling. Note the perpendicular resection as well as the
pathologic defect.
• F, radiograph of the completed root end filling

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. G and H, A 1-year recall photograph and radiograph
demonstrate resolution of the lesion and osseous
regeneration.

PROCEDURAL ERRORS
SEEN AT THE ROOTAPEX
some due to inattention to detail, and others totally
unpredictable

LEDGING
 Any deviation from the original canal curvature results in
the formation of a ledge.
CAUSES
 Inadequate access cavity preparation
 False estimation of pulp space direction
 Failure to pre-curve SS instruments
 Failure to use instruments in a sequential manner
 Attempt to retrieve separated instruments
 Attempt to prepare calcified canals

Relationship between the degree of curvature
and
incidence of ledge formation
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Journal of Restorative Dentistry / Vol - 3 / Issue - 3 / Sep-Dec 2015 • 61

11/13/2018 143
• Recognition:
• instrument can no longer be inserted into the canal
to full working length
• Correction:
 Pre-curved No. 10 file is used to bypass
 Use a lubricant, irrigate frequently to removal
dentin chip,
 Using short file strokes press the instrument
against the canal wall where the ledge is
located.
 Prevention:
• Pre-curving instruments and not “forcing” them in

APICAL transportation
 Moving the position of the canal’s
physiologic terminus to a new iatrogenic
location on the external root surface
 Correction:
• MTA is barrier of choice
• In severe cases where
barrier technique cant be
created corrective surgery
is required

 Prevention:
• Don’t use large instrument initially.
• Correct determination of working
length

PERFORATION
 An artificial opening in a tooth or its root ,
created by boring, piercing or cutting, which
results in a communication between the pulp
space and the pdl tissues
• Incidence 3-10%

• Level: More apical the perforation, more
favorable the prognosis.
• Size: Perforation size greatly affect the
clinician’s ability to establish a hermetic seal.
• Mathematically described as - r2 (r =
radius).
• Time: should be repaired as soon as possible to
discourage further loss of attachment and
prevent sulcular breakdown.

Treatment sequence:
• Should be repaired before proceeding with
definitive endodontic treatment.
1. Haemostatics:
• e.g. Calcium hydroxide, collagen, ferric
sulfate, leave a coagulum behind
• that may promote bacterial growth
compromising the seal

2. Barrier Material:
• Resorbable : Collagen materials: (Collacote)
Calcium sulfate: (Capset)
• Non Resorbable : MTA

Apical perforations
• Through the apical foramen or through the body of the root.
Etiology:
• Instrumentation of canal beyond the apical foramen.
• Incorrect WL or inability to maintain proper WL causes
blowing out of the apical foramen
Treatment:
 Establish a new WL
 The new WL should be established 1- 2mm short of the
point of perforation.

Zipping or ELLIPTICATION
• Transportation or transposition of the apical
portion of the canal

11/13/2018 152
Ledge
Zipping
Perforation

LOSS OF PATENCY
 Canal may suddenly loose patency during a
cleaning and shaping process.
Causes
 Tissue compression,
 Debris accumulation or
 Instrument separation.

Conclusion
• The morphological variation & technical challenges
involved in treatment of apical third is infinite
• The crux of endodontics revolves around efficient &
effective manipulation & obturation of apical third
• So endodontist should have detailed knowledge of the
anatomic variation and mechanical challenges
involved for effective & efficient management during
endodontic therapy

Referrences
• Pathways of pulp – cohen
• Endodontic therapy – weine
• Oral histology – Orbans
• www. Google.com

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