RADIOGRAPHS IN ENDODONTICS
AND LOCAL ANAESTHESIA - II
IMPORTANCE OF RADIOGRAPHY IN ENDODONTICS
The evaluation of pathologic lesions of the head and neck
routinely involves the use of radiographs in attempting to
determine the nature of the disease process
Radiographs are also essential to all phases of endodontic
therapy. They help in :
• During various treatment steps and
• Evaluation of the success or failure of treatment.
Identifying the Pathosis :
The radiographs help in identifying the lesion whether it is
Determining the Root and Pulpal anatomy :
The number of roots/ root canals
Unusual root morphologies
Canal locations with respect to the pulp chamber
Characterizing Normal Structures :
Helps in differentiating the normal from abnormal
1. Determining Working Lengths
2. Moving superimposed structures:
Certain normal anatomic
structures may superimpose on
the apices of the teeth.
Changing the angulations help in
Locating canals :
Evaluating the Obturation:
The radiographs help us to assess the quality of
obturation by helping us to evaluate the
1. Length - if the working length has been maintained
2. Density - the radiopacity of the material
3. Taper of the preparation of the configuration
RECALL / FOLLOW UP
Most of the times the patient does not know the status of
the root canal treatment.
In most cases the patient may be asymptomatic.
In such cases only radiographs help in diagnosing the
There may be evidence of
new lesions :
Or evaluation of the healing / progress of the treatment
LARGE PERI APICAL LESION
LESION DECREASES IN SIZE
LESION REMAINS SAME
LESION INCREASES IN SIZE
RETREATMENT / RETREATMENT +
I. Diagnostic :
The number of films used would depend upon the diagnostic
The first film should give us the basic details about the
Caries → Pulpal involvement → Periapical status
A properly positioned film should permit the visualization of
atleast 3 to 4mm beyond the apex
The most accurate radiographs are made using the paralleling
Less distortion and more clarity
Reproducibility of film and cone placement [ using the XCP ]
Reproducibility : ability to take two or more radiographs of a
given tooth at different time intervals and producing an image
of same/ near to same characteristics.
Especially useful in evaluating the healing of large lesions
In cases of low palatal vault, exceptionally long roots, or
maxillary tori, the paralleling technique is not possible. In such
cases the bisecting angle technique is used
II. WORKING FILMS
These are the films which are used during the treatment
Not essentially given to the patient for a record
Working length radiograph
During obturation [ intermediate ]
Exposure and Film Speed
The exposure gradients
for the working films are similar to
that of the Diagnostic radiographs.
The films should be clear and the apical extent of the image
should be same as that for diagnostic films i.e 3-4mm beyond
the apex must be shown .
The tip of the roots and the tips of the files/master cones
should be easily identified.
The exposure time for the films depends on the speed.
basic principles as those required for diagnostic
But after obturation it is advisable to take atleast two
radiographs at different angulations to visualize any missed
Extrusion of obturation
Obturation short of apex
Normal findings in x-rays
– dentin and enamel have different shades
• due to variation in mineralization
– radiopacity: enamel > dentin > pulp
– cemento-enamel junction should be recognized
– lamina dura
is a layer of compact bone (i.e., cribriform plate or
alveolar bone proper) that lines the tooth socket
– periodontal ligament space
• thin radiolucent area between root and lamina dura
– alveolar crest
• bone that extends between the teeth
• normal level no more than 1.5 mm from cemento-enamel junction
The most consistent radiographic feature aiding diagnosis of
pulpal and periapical lesions is the continuity and shape of
the lamina dura and the width and shape of the PDL space.
Endodontic lesions must encroach on the junction of the
cancellous bone and cortical bone for radiographic detection.
Lesions are larger than they appear radiographically
The cortical plate must have 12.5% volume of bone loss or
7.1% of mineral bone loss to be detected radiographically.
The radiographic description of any lesion can give us
Tissue of origin
Diagnosis or a Differential Diagnosis
A radiograph helps in describing the lesion’s
Effect on adjacent structures
Localized or generalized
Unilateral or bilateral
Relation of the lesion to other structures and anatomic landmarks
If the radiolucency is above the inferior alveolar nerve canal
(IAC), the likelihood is greater that it is odontogenic in origin.
If it is below the IAC, it is unlikely to be odontogenic in origin.
If it is within the IAC, the tissue of origin probably is neural or
vascular in nature.
Many anatomic structures and osteolytic lesions can be
mistaken for periradicular pathoses.
Among the more commonly misinterpreted anatomic
structures are the mental foramen and the incisive foramen.
Initial / immature phase of
Periapical cemental dysplasia
Mature phase of Periapical
These radiolucencies can be differentiated from pathologic
conditions by exposures at different angulations and by
Radiolucencies not associated with the root apex will move
or be projected away from the apex by varying the
• Other anatomic radiolucencies that must be differentiated from
periradicular pathoses are
Median Palatal Suture
Incisive Canal Foramen
Radiolucent lesions :
1. Apical /radicular lamina dura is absent
2. A hanging drop of oil shape . Though a lesion ca be of
3. Radiolucency stays at the apex regardless of change in
4. The cause for pulp necrosis is ,in most cases ,evident
A and B, A straight-on view will cause superimposition of the buccal object (yellow circle)
with the lingual object (red triangle). C and D, Using the tube-shift technique, the lingual
object (red triangle) will appear more mesial with respect to the mesial root of the
mandibular first molar, and the buccal object (yellow circle) will appear more distal on a
second view projected from the mesial. E and F, The object (red triangle) on the lingual
surface will appear more distal with respect to the mesial root of the mandibular first
molar, and the object (yellow circle) on the buccal surface will appear more mesial on a
view projected from the distal aspect.
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