The endodontic periodontic lesion: a diagnostic dilemma

Question 1

Infection from PDL to pulp

Answer 1

Pathogenic bacteria and inflammatory products of perio –> accessory canal/ lateral canals/ apical foramen –> pulpal infection/ necrosis (retrograde pulpitis)

Question 2

Infection from pulp to PDL

Answer 2

Pulpal disease
Procedural errors in RCT
Perforations
Vertical root fractures
----->
Dentinal tubules
Peri-radicular inflammation
-------->
Bone loss + CAL +/- Pus discharge (retrograde periodontitis)

Question 3

Simplified classification of endo-perio lesions (look at diagram)

Answer 3

Primary endo lesion + secondary perio lesion
or
Primary perio + secondary endo lesion
or
'True' combined perio-endo lesion

Question 4

Primary endo secondary perio lesion

Answer 4

 Originally an endo lesion, the
infection spreads from the apex and
along the root to the gingiva
Pulpal infection can also spread from
accessory canals to the gingiva or
furcation

Question 5

Primary perio secondary endo lesion

Answer 5

A periodontal pocket can deepen to
apex & secondarily involve the pulp
Alternatively a perio pocket can infect pulp through lateral
canal

Question 6

‘True’ combined lesion

Answer 6

Two independent lesions (periapical and perio) can coexist and eventually
fuse with each other

Question 7

Abott and Castro Salgado 2009 classification

Answer 7

 Concurrent endodontic and
periodontal disease
without communication
 Concurrent endodontic and
periodontal disease with
communication

Question 8

Communication

Answer 8

 Knowing if the lesions are
communicating can be useful
 Non-communicating lesions
suggest a ‘true’ combined lesion
with independent aetiologies
 However, communicating
lesions may be ‘true’ combined
lesions which have merged, or
lesions which have started primarily as perio or endo and
then spread to the other
 Knowing original source of infection can have an
implication for management
and prognosis of case

Question 9

Diagnosis

Answer 9

History 
Examination
-endo
-perio
Special tests
-sensibility testing
-radiographs
-other tests?

Question 10

History - clinical symptoms

Answer 10

May be no symptoms
Swelling of gingiva
Pus discharge
Fistula tract
TTP
Mobility
Sign: pocket formation

Question 11

Examination

Answer 11

Endodontic
 Restorative status
 TTP
 Tenderness in sulcus
 Swelling/ sinus
Periodontal
 Probing around tooth (all the way around the tooth - pocket can be very narrow)
 Pus discharge from pocket
 Mobility

Question 12

Special testing

Answer 12

Sensibility testing
-cold testing (ethyl chloride)
-EPT
-tooth should be -ve to both tests to confirm non-vital status
Radiographs
Consider tooth sleuth
and transillumination to rule out root fracture if this is a possibility

Question 13

Radiographs

Answer 13

PA radiographs are most appropriate
modality to assess perio endo lesions
Vertical perio
defect often present
Radiolucency around apex will be present
‘J-shaped lesion’ may be present 
OPT can be used, but this would only be indicated if multiple sites
needed to be radiographed,
likely for perio
assessment
-further IO
radiographs would likely be needed in addition
CBCT scan only indicated when
conventional radiography
does not provide sufficient detail
-examples might include complex 3-D anatomy or
suspicion of other causes such as resorption or
perforation

Question 14

Management of perio endo lesion

Answer 14

Treatment depends upon initial diagnosis

• primary endo secondary perio lesion –> RCT only
• primary perio secondary endo –> RCT and perio therapy
• ‘true’ combined lesions –> RCT and perio therapy

Question 15

Rationale for management: Primary endo secondary perio lesions

Answer 15

Endo
aetiology
Endo infection just happens to be draining via PDL
Periodontal lesion usually presents as narrow defect
Endo treatment will usually resolve the issue as it will eradicate source of infection
Perio defect is often very narrow and not really conducive to
instrumentation
Review after 3 months and instigate
non-surgical periodontal therapy if the
pocketing is still present
Review after another three months – if
still no resolution consider other
options such as surgical intervention

Question 16

Rationale for management - primary perio secondary endo lesion

Answer 16

Primary perio secondary endo
lesions have a periodontal
aetiology, but the tooth has
become non-vital so also requires
RCT
This means endodontic therapy
and periodontal therapy are both
required and it is best to
undertake these simultaneously 
Review after 3 months and
instigate further non-surgical
periodontal therapy if the
pocketing is still present
Review after another 3 months – if still no resolution
consider other options such as
surgical intervention

Question 17

Rationale for management - ‘true’ combined lesions

Answer 17

 ‘True’ combined lesions have
an endodontic and
perio aetiology
 They may or may not communicate
 Either way, endodontic and
periodontal therapy is indicated
 Again, it is best to undertake these simultaneously
 Review after 3 months and
instigate further non-surgical
periodontal therapy if the
pocketing is still present
 Review after another three
months – if still no resolution
consider other options such as
surgical intervention

Question 18

Alternative management options

Answer 18

Some people advocate placing
CaOH inside
prepared canal rather than
obturating whilst assessing response to perio therapy
-obturation only undertaken once response to perio therapy seen
-no evidence to
suggest this is more preferable treatment regimen
Surgical intervention may be
indicated earlier with for example very deep pockets, not conducive to non-surgical perio therapy
In molars, if one
root considerably more affected than another root, consideration
should be given to
undertaking root
resection or hemisection
-often, root resection is
undertaken on the mesio-buccal
or disto buccal roots of upper
molar teeth and hemisection is
undertaken on lower molars

Question 19

Prognosis

Answer 19

Primary endo secondary perio: generally good

Primary perio secondary endo / ‘true’ combined lesions: prognosis depends on extent of perio bone loss

Question 20

Lesions masquerading as perio-endo lesions

Answer 20

 Developmental grooves
 Perforations
 Root fracture
 Resorption

Question 21

Developmental grooves

Answer 21

Developmental grooves can predispose to formation of
deep perio pocket, which if untreated can result in pulp death (primary perio secondary endo
lesion)
Management involves endo treatment and
perio therapy, but surgery may be required due
to groove

Question 22

Perforations

Answer 22

Perforations can occur during
endodontic treatment or
during placement of endo post or dentine pin
Clinically perforation may present as deep pocket
leading to site of
perforation

Question 23

Perforations - radiographically

Answer 23

Radiographically,
perforation will often lead to bone loss around site of perforation
Perforation may or
may not be
radiographically obvious as radiograph is a 2D
view of 3D object

Question 24

Management of perforations

Answer 24

Requires assessment of restorability of tooth
If unrestorable, the tooth will
require extraction
If restorable the tooth will
require repair of the
perforation, either internally or externally using a
biocompatible material such
as MTA or 
 Biodentine
This management is probably
best undertaken by an endodontist

Question 25

Root fracture

Answer 25

Root fracture may present very similar to a perio-endo
lesion (particularly primary endo secondary perio) with
a narrow, deep, isolated perio pocket
‘J-shaped’ lesion may also be present radiographically

Question 26

Root fracture management

Answer 26

Involves assessing extent of fracture

Any vertical fracture extending on to root face will require extraction

Question 27

Root resorptions

Answer 27

Root resorption relevant to this subject include:
External root resorption
 External cervical resorption
 External replacement resorption
Internal root resorption

Question 28

External cervical root resorption

Answer 28

 Unknown aetiology
 May be associated with previous
trauma
 Resorption usually starts
subgingivally in the cervical region
 The pulp is usually vital and only becomes involved when the lesion
has progressed extensively
 Often asymptomatic

Question 29

External cervical may be mistaken for

Answer 29

Perio endo lesion
-pocketing may be present around area of resorption
However, resorption lesion fills with gingival tissue, so pocketing is rarely deep
Additionally, radiographic appearance characteristic of resorption

Question 30

External cervical root resorption - special tests

Answer 30

 CBCT may be useful to assess the
extent of the lesion
 Treatment involves surgical
exploration of the lesion followed
by repair
 Endodontic treatment may or may
not be required
 This is specialist treatment and
referral should be instigated as
soon as a diagnosis is suspected

Question 31

External replacement resorption

Answer 31

Root surface gradually replaced with bone – also known as ankylosis
Often has a traumatic origin
Can be transient and self-limiting, but will often progress until complete root
replacement occurs
Clinically, when the lesion has progressed
significantly, a catch may be present at gingival margin, which can mimic a perioendo lesion

Question 32

External replacement resorption diagnosis

Answer 32

 Diagnosis is based on radiological appearance and clinical
examination, which will show a high-pitched, metallic
sound on percussion
 The tooth will be non-mobile and may become infraoccluded
in children who are still growing
 There is no treatment which can stop the ankylosing
process

Question 33

Internal root resorption

Answer 33

Occurs entirely within the canal system
Results in an ovoid expansion of the root
canal
Outline of the canal will be lost around
the area of resorption
The pulp will likely be chronically inflamed
A ‘pink spot lesion’ may be visible through
the enamel
Tooth usually partially vital and there
may be symptoms of pulpitis
If resorption
continues to expand
and eventually
perforates through root a perio
lesion may develop

Question 34

Management of internal root resorption

Answer 34

Endo treatment required
Obturation can be difficult due to unusual canal anatomy
Thermal obturation techniques
(involving backfill with molten GP)
required