Endodontic Radiology

Question 1

DIAGNOSTIC RADIOGRAPHS? (2)

Answer 1

How many multi-rooted Maxillary Canines have you seen?
If it doesn’t look right; consider a better angulation

Question 2

(2) are paramount in
helping to determine a correct
Diagnosis

Answer 2

Optimization of image quality
and relationship to the area of
concern

Question 3

Must be distinct and include all of
the areas of concern in proper
orientation without cone cuts,
overlapping, elongation or
foreshortening. Must include all of
the tooth and at least – mm. apical
to the end of the root.

Answer 3

5

Question 4

All Posterior teeth
REQUIRE

Answer 4

2 P/A
radiographs (straight-
on and 20 degree H.
angled).

Question 5

Always a good idea to
take multiple angles to
help guess the

Answer 5

3-D
anatomy

Question 6

What does a 5 year old sloppy X-ray tell you?
*

Answer 6

It should tell you to take current radiographs!
Current is 1-2 mos. (UNLESS SOMETHING HAS CHANGED)
Drop-off perio pocket or a DST could indicate a new vertical
root Fx
A new restoration or any new information, complaint.
SEE WHAT IS HAPPENING NOW

Question 7

Do Radiographs have Historical Value?

Answer 7

A SERIES of RADIOGRAPHS over
time with similar angulation and
exposure can be very helpful when
following a new, developing or
healing lesion.

Question 8

1. Benefits of Endodontic Radiology
   (4)

Answer 8

*Suggests LEOs & other Pathosis
*May Indicate Unseen Canals & Proximal Anatomy
*Largely locates most curvatures
*Assists in Working-Length Determination

Question 9

2 CANALS:
Which Canal?

Answer 9

Changes of Horizontal
Angulation = “SLOB” rule

Question 10

Modern diagnostic digital radiography is
without risk when appropriate

Answer 10

radiation hygiene techniques are
employed.
There should be no question about X-Ray
safety for adequate diagnostic/TX
purposes

Question 11

Many
Opportunities exist
for CONFUSION and
Inaccurate
Interpretation

Result can be Inaccurate Dx
leading to INCORRECT
Treatment

Universal Temptation to Dx from
X-RAY alone. (3)

Answer 11

Artifacts
poor resolution
wrong angle

Question 12

Other Detractors:
(3)

Answer 12

Normal or Aberrant Anatomy
Apparent LEO is another entity
Oral manifestation of Systemic Disease Unexpected
Occurrence, etc.

Question 13

The 3 Biggest Risks of
Endodontic Radiology

Answer 13

Attempting to
DIAGNOSE
from
RADIOGRAPHS
ALONE
Seeing
SOMETHING on
the FILM that is
NOT THERE
FAILING TO SEE
SOMETHING
on the FILM
that IS THERE

Question 14

Unless you LIKE spending Time & $ HERE:
The Court deals with both:
ERRORS of —
ERRORS of —

Answer 14

COMMISSION
OMISSION

Question 15

— curvatures are
more easily noticed than
—

Answer 15

Mesio-distal
buco-lingual

Question 16

When you see a “Bullseye”
on an image, You are seeing
a

Answer 16

facial or lingual root tip “on
end”. You don’t know if it
curves to the Facial or the
Lingual (good opportunity to
refer).

Question 17

This 4th (Disto-Lingual) root is seen
most frequently in

Answer 17

Native American
and Asian populations. Often the D-L
root and canal curve sharply to the
facial to present this classic
appearance.

Question 18

This information can be of great value
to the operator in being able to

Answer 18

visualize the unusual anatomy
and avoid misadventures.

Question 19

If we place a file in a single canal at a
known length, and radiograph it, we
can thereby measure the

Answer 19

length of the
canal & adjust our file’s length to the
desired length (WL) at which we want
to do our work inside the tooth.

Question 20

How accurate would you be without a
radiographic image?
Radiographs extend our effective vision
We want to work and fill at —
mm. short of the canal exit in
most cases.

Answer 20

1.0

Question 21

How do you tell WHICH canal?
Since the radiograph is only 2 dimensions and
you can’t tell which is facial or lingual, a problem
is presented:
(3)

Answer 21

1. You could take a separate XR of each canal with a
   single file in a known canal. You would then need to
   label the X-rays carefully/correctly not to become
   confused. Wastes TIME*
2. You could place files of varying radiographic
   appearance in each of the canals and remember
   which file went in which canal. (Usually only 1 type
   of file available)
3. You could increase the vertical angle of the
   radiograph; the lingual canal would be longer, the
   buccal shorter. However the true lengths would be
   grossly distorted & it would be virtually useless for
   accurate length determination.

Question 22

How do you tell WHICH canal?

Answer 22

• You should take a straight-on
  radiograph and then a second
  radiograph with a 20º change in
  horizontal angulation as in taking a
  “Shift-Shot”. All you have to
  remember is which direction the X-
  Ray cone was moved from straight-
  on (i.e. Mesial or Distal)

Question 23

If you guess
wrong; you will
— the
problem you
hoped to
correct

Answer 23

compound

Question 24

Change the — angle for a Shift-Shot

Answer 24

horizontal

Question 25

Now apply the “SLOB RULE”: Same Lingual, Opposite Buccal
As the angle of the X-Ray cone is shifted,

Answer 25

the object furthest from the XR
cone (lingual) will move with the XR cone.
(Conversely, the object closest to the cone will move away from the
cone)

Question 26

So: Lower molar XR cone shifted mesially . .

Answer 26

The M-buccal canal will appear
to shift to the distal. (away from cone) The M-lingual canal will now
appear to have moved mesially to the facial canal. (toward the cone)
SLOB

Question 27

A distal cone shift will result in the

Answer 27

M-buccal canal appearing to shift to the
mesial and the M-lingual canal will appear to be distal to it.

Question 28

XR shifted to Mesial;

Answer 28

ML & DL
canals now appear to be mesial
to buccal canal and moving
TOWARD the cone & the MB &
DB canals move AWAY FROM the
cone toward the distal

Question 29

The lingual canal moves to the — on a mesial shift shot.

Answer 29

mesial

Question 30

Aim cone from Distal, now
mesio-buccal > to —;
palatal > to —

Answer 30

mesial
distal

Question 31

2. Common periapical Lesions of
   Endodontic Origin (LEO’s):
   (2)

Answer 31

1. Thickened PDL
2. P/A Radiolucency

Question 32

1. Thickened PDL

Answer 32

We can see the thickening of the PDL on this
radiograph but this does NOT PROVE it is a
LEO. (could be traumatogenic occlusion)
The radiograph is NOT DIAGNOSTIC as the
crown is NOT shown and we have no idea if
the etiology is a LEO (e.g. caries) or merely
thickening arising from traumatic occlusion or
recent trauma. Look 4 the INJURY
We must employ: Diagnostic XRs, History,
Clinical Examination, and Clinical & Sensibility
Testing to arrive at an ETIOLOGY to know.
Only then do we have our Supported Diagnosis.

Question 33

2. P/A Radiolucency

Answer 33

Here we can see readily see an
obvious etiology for the PAR.
With no medical or dental history
nor clinical findings to the
contrary . . . . we can be relatively
secure in our justification of a
LEO in this case based on pulp
testing and apparent depth of
injury from caries.

Question 34

A radiolucency of endodontic origin is often
BUT not always associated with a pulpal DX of

Answer 34

necrotic pulp.

Question 35

2. P/A radiolucency
   What is it:
   (3)

Answer 35

• Abscess
• Granuloma
• Cyst

Question 36

It is NOT possible to
accurately diagnose these
conditions from the
radiograph.
*If it is important or there
is a question that it may
be something else of
concern, a — may be
taken.

Answer 36

BIOPSY
*Some recommend a
BIOPSY of all surgical
tissue removed – some

Question 37

— often NOT seen on
standard dental XR

Answer 37

VRF

Question 38

— is either in the
plane of the film or
obscured by the root
itself (esp. in the case of
RCT teeth)

Answer 38

Crack

Question 39

— often visible on XR

Answer 39

HRF

Question 40

— here may be a
CLUE

Answer 40

Mobility

Question 41

A distinguishing characteristic of a radiographic lesion
of endodontic pathosis (LEO) is that

Answer 41

the radiolucency
stays at the apex regardless of cone angulation.

Question 42

can YOU tell the LEOs from normal
anatomy or systemic pathology?

Answer 42

*It is NOT TRUE that ALL “periapical
radiolucencies” that will be presented
radiographically are, in fact, LEOs.
*Again, it is a mistake to diagnose primarily
from the radiograph as Differential
Diagnosis must be made on a logical basis
as supported by evidence beyond the
appearance of the radiographic image itself.

Question 43

3. Differential DX: a. Common Anatomical
   Landmarks
   (5)

Answer 43

Maxillary Sinus
Nasal Cavities
Incisive Canal
Mental foramen*
Mandibular Depression (Concavity)

Question 44

MAXILLARY SINUS

Answer 44

The Maxillary sinus is often
superimposed on maxillary
posterior apices. Do not be
fooled!
Learn to carefully examine the
lamina dura and periodontal
ligament at the apex. You should
see the PDL space distinctly
uniform width and un-
interrupted.

Question 45

NASAL CAVITIES

Answer 45

The nasal cavities are often superimposed on
the central and lateral apices (especially when a
high bisecting angle technique is used)
Do your pulp testing, percussion, palpation.
Also take additional angled radiographs to see
the anatomical area move away from the apices.
Lamina Dura remains intact with normal teeth.
Look for a REASON for this to show pathology
(caries, trauma, etc.) if none seen, there IS no
reason and this is not LEO pathology.
Pathology is SELDOM bilaterally symmetrical

.

Again, the Lamina
Dura & Pulp Tests are
the key!

Question 46

Incisive Foramen/Canal

Answer 46

Don’t confuse normal anatomy with
pathology (Lamina Dura is key)
If radiolucent area moves AWAY FROM the
apex on multiple films, it is NOT associated with
the apex and therefore is probably NOT a P/A
lesion.
Test vitality of teeth in area. Why?
We MUST pulp test every
tooth which we plan to
restore.
Look for a REASON for LEO Pathology

Question 47

MENTAL FORAMEN

Answer 47

Possibly the most common
Anatomical Landmark to be
confused w LEO* = Classic
Can masquerade as P/A lesion. Angled XR
shows it moves AWAY from the apex = NOT a
P/A lesion. Confirm with Pulp Testing.
Lamina Dura is not disturbed. Is there a
REASON for pathology?
If radiolucent area moves WITH the apex on
multiple angled films, it is associated with the
apex and therefore is probably a P/A lesion.
Suspect all apparent bilateral lesions as being
anatomical or systemic and NOT of pulpal
origin until proven otherwise.

Question 48

3. Differential DX: b. Non-endodontic
   Radiolucencies which may mimic LEOs
   including oral manifestations of systemic disease
   (6)

Answer 48

Lateral Periodontal Cyst (abscess)
PCOD
FOD
Hyper-parathyroidism
Central giant cell granuloma
Neoplasias

Question 49

Lateral
Periodontal cyst (abscess)

Answer 49

*May be asymptomatic OR: may mimic
symptoms of SAP or AAA
(CC = pain, swelling, palpation +, perc++????).
Lesion is NOT generally at apex.
*PT’s =vital pulp VIP!
*LD may or may not be intact
*No restorations or clinical aberrations . . .
CAUSE??
*Etiology=infected perio. Pocket
–If it is able to drain = asymptomatic
–If unable to drain = symptomatic

Question 50

Non Endodontic Lesions: Periapical Cemental Osseous Dysplasia (PCOD)
AKA: “Cementoma”
Periapical fibrous dysplasia,
Periapical cemental dysplasia

Answer 50

A dysplastic, rather than pathologic or
inflammatory condition.
Characteristics:*
All teeth were vital and asymptomatic
Radiolucent vs radiopaque (mixed)

Question 51

PCOD
This is also one of the
more common
radiolucencies that
causes

Answer 51

unneeded endo
treatment!!!
Restorations as needed
No further TX is needed

Question 52

Non Endodontic Lesions: Central Giant Cell
Granuloma

Answer 52

CGCG is a benign intraosseous
lesion found in the anterior of the
maxilla and the mandible in
younger people (before age 20). It
is characterized by large lesions
that expand the cortical plate and
can resorb roots and move teeth.
It is composed of multi-nucleated
giant cells. It has a slight
predilection for females.
Radiographically it appears as
multilocular radiolucencies of
bone.
If it doesn’t look right or make
sense in a diagnostic sense,
DON’T do ANYTHING except
REFER to Oral Pathologist,
Endodontist, Oral Surgeon, MD

Question 53

Non Endodontic Lesions: Neoplasias
Metastastic Breast CA

Answer 53

*Causes “spiking” & resorption
of roots
*Poorly defined borders of
lesion
*Loosening of teeth
*Pulps may still be vital
*Symptoms of neoplasia, esp in
mandible—may be pain as well as
paresthesia
*VIP lesion is usually ragged and
asymmetrical!

Question 54

Many MORE non-endodontic
radiolucencies which appear to be
associated with root apices may
present:

Answer 54

Osteosarcoma
*Ameloblastoma
*Ameloblastic Fibroma
*Dentigerous Cyst
*Globulomaxillary Cyst
*Keratocyst
*Median Palatine Cyst
*Nasopalatine cyst
*Primordial Cyst
*Residual Cyst
*Scar Tissue
*Traumatic Bone Cyst

Question 55

BOTTOM LINE: Before you initiate ANY RCT,

Answer 55

be certain that
you have documented and supported justification for doing
so. (Standard of Care) Will your records stand up in Court 2
years hence?

Question 56

CBCT Radiography
*Capable of essential creating multiple sections
of an area to accurately display:
(4)

Answer 56

–Unusual or extra canals
–Location & Extent of cracks
–Aberrant anatomical features
–Otherwise unseen pathology
Becoming the STD. of
CARE in advanced
endodontics today.