PERIRADICULAR
LESIONS of pulpal
origin
Definition
 Apical
periodontitis is an inflammatory
disorder of the periradicular tissue caused
by a persistent microbial infection of the
root canal system of the affected tooth
In other words
 Apical
periodontitis (AP) is a host
response to infections by microbes and
the subsequent inflammatory response
 Apical
periodontitis includes the infection
and inflammation of the lateral and furcal
locations.
 The
root canal and the pulp chamber are
niche environments for the causative
organism
Biofilms

Bacteria form biofilms and these pathological
bacteria are embedded in the biofilms

Biofilms protect the bacteria from antibiotic
attack and make them a X 1000 more resistant
to the effects.
Infection portals
 Pulp
becomes infected by

Carious exposure

Leaking restorations

Dentinal tubules

Fractures or cracks
Inflammatory response
 The
antigens and bacterial toxins
percolate into the surrounding tissue
 Most
likely anaerobic bacteria invade that
provoke an inflammatory response i.e.

Chemotaxis

Enzymatic breakdown with the subsequent
release of antigens
The host mounts a immune response
consisting of several classes
intercellular messengers and antibodies.
This response destroys much of the
peripical tissue
This results in the formation of various
types of apical periodontal lesions.
The defence reaction minimises the
spread of infection.
It cannot eliminate the microbes
entrenched in a necrotic root canal , and
biofilm.
 Treatment
is required via surgical or non
surgical endodontic therapy as biofilms
protect the bacteria from the host
defenses.
Classification of AP
 Apical
periodontitis is an inflammatory
disease and classification is based on
symptoms , aetiology or histopathology.
Nomenclature and Classification
 Numerous
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terms are used such as
Apical granulomas
Apical cysts
Periapical lesions
Periapical osteitis
Three main clinical groups
 symptomatic(acute)
apical periodontitis
 asymptomatic(chronic)
periodontitis
 apical
abscess
apical
Symptomatic(acute)
Apical Periodontitis
The principal causes are irritants diffusing
from an inflamed or necrotic pulp.
Negative vitality test not always accurate
Pain!!!(WHY?)
Asymptomatic(chronic) Apical
Periodontitis
 Preceded
by an acute episode
 lesion frequently develops and enlarges
without any subjective signs and
symptoms
Causes
1. Inadequate endodontic procedure
2. Low grade pathogenicity/ irritant
3. Pathosis is a long-standing “smoldering”
lesion
Asymptomatic(chronic) Apical
Periodontitis(Cont)
 Non
vital respnse
 Radiographic evidence is the key
 Called a peri radicular granuloma or
periradicular cyst.
 Periradicular Granuloma. Nobuhara and
del Rio(JOE1993;19:315) showed that
59.3% of the periradicular lesions were
granulomas, 22% cysts, 12% apical scars,
and 6.7% other pathoses
Histologically, the periradicular granuloma
consists predominantly of granulation
inflammatory tissue with many small
capillaries,
fibroblasts,
numerous
connective tissue fibers, inflammatory
infiltrate, and usually a connective tissue
capsule
Apical periodontitis (granuloma) with contained
epithelium. Epithelial cells of periodontal ligament have proliferated
within new inflammatory tissue. The epithelium tends to ramify in a
reticular pattern (straight arrow) toward receding bone. It also may,
as in this case, apply itself widely to the root surface (curved arrow).
Infiltration of epithelium by round cells is everywhere apparent.
Human tooth. Reproduced with permission from Matsumiya S.Atlas
of oral pathology. Tokyo: Tokyo Dental College Press; 1955.
Periradicular Cyst.
 Periradicular
cyst shows a central cavity
lined by stratified squamous epithelium
 This lining is usually incomplete and
ulcerated
 The lumen contains a pale eosinophilic
fluid and occasionally some cellular debris
Apical cyst with marked inflammatory overlay. Round
cells permeate both the epithelium and the connective tissue immediately
deep to it. Spaces indicate where crystalline cholesterol has
formed within the cyst. Bone formation is evident (arrow). This
may reflect narrowing of the width of the connective tissue zone, as
occurs in some apical cysts. Human tooth. Reproduced with permission
from Matsumiya S. Atlas of oral pathology. Tokyo: Tokyo
Dental College Press; 1955.
Condensing Osteitis
 Inflammation
of periradicular tissues of
teeth usually stimulates concurrent
osteoclastic and osteoblastic activities.
 Osteoclastic (resorptive) activities are
usually more prominent than osteoblastic
(formative)
 Condensing osteitis is associated with
predominant osteoblastic activity
Condensing Osteitis

(CONT)
attributable to a special balance between host
tissues and the root canal irritants.
 Condensing osteitis, or chronic focal sclerosing
osteomyelitis, is a radiographic variation of AAP
and is characterized as a localized
overproduction of apical bone.
 usually observed around the apices of
mandibular posterior teeth with pulp necrosis or
chronic pulpitis
Condensing Osteitis

(CONT)
The tooth associated with condensing osteitis
may be asymptomatic or sensitive to stimuli.
Apical condensing osteitis that developed in response to
chronic pulpitis. Additional bony trabeculae have been formed and
marrow spaces have been reduced to a minimum. The periodontal ligament
space is visible, despite increased radiopacity of nearby bone.
APICAL ABSCESSES
 An
abscess is a localized collection of pus
in a cavity formed by the disintegration of
tissue
 Apical abscesses can be divided into
symptomatic or asymptomatic conditions
APICAL ABSCESSES
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Symptomatic Apical Abscess A sudden egress of
bacterial irritants into the periradicular tissues
severe sequelae, acute osteitis and cellulitis.
Accompanied by exudate formation within the
lesion
May occur without any obvious radiographic signs
infection and rapid tissue destruction arising from
within AAP( Phoenix abcess)
APICAL ABSCESSES/clinical

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May or may not have swelling
Swelling may be localized or diffuse
Varying degrees of sensitivity to percussion and
palpation
No pulp reaction to cold, heat, or electrical
stimuli as the involved tooth has a necrotic pulp
Radiographic features of the SAA vary from a
thickening of the periodontal ligament space to
the presence of a frank periradicular lesion
Radiographic features of symptomatic apical abscess.
The patient developed sudden symptoms of pain and facial
swelling. Radiographically, a lesion is apparent apically to the maxillary
left lateral incisor, that did not respond to vitality tests, confirming
pulpal diagnosis of necrosis.
Asymptomatic Apical Abscess
Asymptomatic apical abscess (AAA), also referred to as
suppurative apical periodontitis, is associated with a
gradual egress of irritants from the root canal system
into the periradicular tissues and formation of an exudate.
The quantity of irritants, their potency, and their
host resistance are all important factors in determining
the quantity of exudate formation and the clinical signs
and symptoms of the lesion. Asymptomatic apical
abscess is associated with either a continuously or
intermittently draining sinus tract.
 WHO
uses a symptomatic classification
based on clinical signs
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Acute apical periodontitis
Chronic apical periodontitis
Periapical abscess with sinus
Periapical abscess without sinus
Radicular cyst
Histopathological classification
(Nair PNR: Pathology of Apical Periodontitis)
In order to understand the disease
process a histopathological classification
is used:

1.
2.
3.
4.
The distribution of pathological cells in the
lesion
Presence or absence of epithelial cells
Transformation of a lesion into a cyst
The relationship of the cyst cavity to the
affected root
Histopathological classification
 Acute
apical periodontitis - an acute
inflammation of endodontic origin . A
distinct focus of neutrophils have to be
present


Primary or initial short lived inflammation in a
healthy periodontium.
secondary or exacerbating when an acute
episode occurs on a preexisting chronic
lesion *also called a phoenix abcess
Histopathological classification
 Established
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chronic apical periodontitis
Long standing inflammation
presence of granulomatous tissue
Cells are lymphocytes , plasma cells and
macrophages
Lesion may be epithelialised or nonepithelialised
Histopathological classification
 Periapical
true cyst is an apical
inflammatory cyst with a distinct
pathological cavity completely enclosed in
an epithelial lining so that NO
communication to the root canal exists
Histopathological classification
A
periapical pocket cyst is an apical
inflammatory cyst containing a saclike
epithelium lined cavity that is open and
continuous with the root canal
Histopathologically the lesions of AP can be classified as acute, chronic ,or cystic .AAP may be (A.)
primary or secondary(B) and is characterized by a focus of PMN, (C) major component are
lymphocytes plasma cells and macrophages, (D) true cysts enclosing the lumina and pocket cysts
(E)cavity is open to the root canal. Arrows indicate the direction of in which the lesion can change.
Important points
 Bacteria
are anaerobes
 Bacteria have to be present
 There has to be a portal for infection to
occur i.e.

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Caries
Clinical procedures
Fractures
Dentinal tubules
To treat or not to treat?
 Anatomic
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considerations
Root shapes?
Can you remove infected hard and soft tissue
Give disinfecting agents access to the apical
canal space
Create space for the delivery of medicaments
and subsequent obturation
Retain the integrity of the radicular structures
To treat or not to treat?
 Is
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the tooth restorable?
Is there an adequate ferule, the amount of
remaining tooth structure
Is root decay present
Vertical fractures
Post preparations in teeth
Anatomical positions of the tooth
Occlusal forces on the tooth
To treat or not to treat?


Restorative requirements of the tooth
Aesthetic requirements
 Sclerotic
canals
Surgical
 Posterior

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part of mandible
Inferior dental nerve
Thickness of mandible
Mental foramen
Facial artery
PDL
Consider alternative
Surgical
 Posterior
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Sinus perforation with infected root fragments
Palatal access
 Anterior


part of Maxilla
maxilla / mandible
Long roots
Inclinations (mandible) and mental
protuberance
 Prepared
teeth are anatomically more
difficult to treat
Endodontic and
periodontal relationships

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Vascular connections exist between the
pulp and periodontal ligament.
Pulp and periodontal problems are
responsible for more than 50% of tooth
mortality.
There is no doubt that an interrelationship
exists in diseases that affect both the pulp
and periodontium
 When
the pulp necroses for whatever
reason products from pulp degeneration
reach the supporting periodontium. This is
characterised by bone loss, tooth mobility ,
and sometimes sinus tract formation.
 Apically if this occurs , a periradicular
lesion forms which can extend crestally
(Reverse pocket is formed)
Periodontal disease may have a
gradual , atrophic effect on the
pulp.
Periodontal treatments such as
deep root planing or curettage, or
localized irritants e.g. acids may
cause pulpal irritation.is
Apical foramina have been shown to be the
most direct root of communication to the
periodontium.
In addition lateral or accessory canals with
28% at the furcation.
Periradicular periodontitis
 Acute,
painful to biting or percussion, the
vitality may or may not be positive. No
periradicular radiolucency and widened
PDL, Apical 1/3 of root
 Chronic , no clinical symptoms, negative
vitality test , periapical radiolucency ,
altered patient sensation
Periradicular abcess
 Acute,
sensitive to pressure and
palpation, negative vitality test , increased
mobility , increased pdl space, associated
temperature
 Chronic, no clinical symptoms, no vitality
response periradicular radiolucency on
radiograph, suppurative lesion(pus
drainage )
 Periodontal


considerations
Channels exist between pulp and periodontal
tissue
These include neural pathways, lateral canals
dentinal tubules, palato-gingival grooves
periodontal ligament alveolar bone , apical
foramina and vascular and lymphatic
pathways
Endodontic / Periodontic
Relationships
 Primary
endodontic -lesions lateral
aspects of the root sinus tract along the
root – gutta-percha trace
 Primary endodontic with secondary
periodontal involvement –accumulation of
plaque / calculus apical migration of tissue
Endodontic / Periodontic
Relationships
 Primary
periodontal lesions -deposit in
sulcus migrates apically. Vital pulp got to
distinguish this from previous both look
the same.
 Primary periodontal secondary endodontic
involvement-accentuated pain from lesion.
Hard to separate from endo perio
Endodontic / Periodontic
Relationships
 True
combined lesion- damage to pulp
and periodontium at the same time that
may coalesce classic ‘J’- lesion
 Treatment
can include the resection of
roots (multirooted) , but lesions associated
with cracked roots , older patients and
posts. Regeneration procedures.
NONENDODONTIC
PERIRADICULAR LESIONS

Got to differentiate between pulpal pathology and nonendodontic origins of alterations in bone morphology.


38 radiolucent lesions and other abnormalities of the
jaws.Three of these lesions, dental granuloma, radicular
cyst, and abscess, are categorized as being related to
necrotic pulps. In addition,16 radiopaque lesions of the
jaws, 3 of which, condensing osteitis, sclerosing
osteomyelitis, and Garré’s osteomyelitis, are also related
to pulpal pathosis
Never assume a radiolucency is pulpal pathology.
NONENDODONTIC
PERIRADICULAR LESIONS
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Lesions of the jaws categorized as odontogenic or
nonodontogenic in origin
Odontogenic lesions arise from remnants of
odontogenesis (or the tooth-forming organ), either
mesenchymal or ectodermal in origin.
Nonodontogenic lesions trace their origins to a variety of
precursors and therefore are not as easily classified.

Differentiating between lesions of endodontic and
nonendodontic origin is usually not difficult. Pulp vitality
testing, when done with accuracy, is the primary method
of determination; nearly all nonendodontic lesions are in
the region of vital teeth, whereas endodontic lesions are
usually associated with pulp necrosis, giving negative
vitality responses. Except by coincidence,
nonendodontic lesions are rarely associated with
pulpless teeth.
Odontogenic Cysts
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Dentigerous Cyst
Lateral Periodontal Cyst
Odontogenic Keratocyst
Residual Apical Cyst.
Lateral periodontal cyst.Well-circumscribed radiolucent
area in apposition to the lateral surfaces of the lower premolars
(black arrows demarcate the extent of lesions). No clinical signs or
symptoms were noted. Pulps tested vital.
Bone Pathology: Fibro-osseous Lesions
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Periradicular Cemental Dysplasia
Osteoblastoma and Cementoblastoma
Cementifying and Ossifying Fibroma.
A, Periradicular cemental dysplasia (osteofibrosis), initial stage. Pulps in both teeth are vital.
B,
Transition to the second stage is developing. C, Biopsy of periradicular osteofibrosis, initial
stage. Fibrous connective
tissue lesion has replaced cancellous bone.
Cementoblastoma. The lesion is a fairly well-defined
radiopaque mass surrounded by a thin radiolucent line. It has also
replaced the apical portions of the distal root of the first molar
Ossifying fibroma. The patient presented with pain.
The pulp was vital, indicating that this was not an endodontic
pathosis. Root canal treatment was followed by root end removal
and excision of the lesion. Biopsy confirmed the diagnosis
Odontogenic Tumors

Ameloblastoma.
Two examples of ameloblastoma. A, Surgical specimen
of infiltrating ameloblastoma of mandible. B, “Unicystic” ameloblastoma.
This solitary lesion has displaced teeth much as an apical cyst
would do. The teeth are vital.
Nonodontogenic Lesions
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Central Giant Cell Granuloma.
Nasopalatine Duct Cyst
Simple Bone Cyst.
Globulomaxillary Cyst
Enostosis.
Malignancies
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Carcinomas or sarcomas of various types are found in the jaws,
rarely as primary but usually as metastatic lesions
Carcinoma. Generally found in older patients, involvement of the
jaws (usually the mandible) is by metastasis from a primary lesion
elsewhere
Carcinoma lesions of the jaw may also manifest pain and swelling,
loosening of teeth, or paresthesia, similar to endodontic pathosis
Radiolucent jaw malignancies have been mistaken for periradicular
lesions.
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Radicular cyst
Residual cyst
Paradental and mandibular infected
buccal cysts
Mandibular Infected Buccal Cyst
Lateral periodontal cyst
Glandular odontogenic cyst
Odontogenic keratocyst
Gorlin syndrome