Introduction to Endodontics Forth Year

1. RADIOGRAPHS IN ENDODONTICS
AND LOCAL ANAESTHESIA - II

2. 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 :
• Diagnosis
• During various treatment steps and
• Evaluation of the success or failure of treatment.

3. DIAGNOSIS
Identifying the Pathosis :
The radiographs help in identifying the lesion whether it is
 Pulpal
 Periapical
 Periodontal
 Bony lesions

4. Determining the Root and Pulpal anatomy :
 The number of roots/ root canals
 Unusual root morphologies
 Root curvatures
 Canal locations with respect to the pulp chamber
 Bifurcations/ trifurcations
 Calcifications

5. Characterizing Normal Structures :
 Helps in differentiating the normal from abnormal
structures.

6. TREATMENT
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
separating them.

7. Locating canals :
 Extra canals
 Missed canals

9. 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
- overfilling
- underfilling
2. Density - the radiopacity of the material
3. Taper of the preparation of the configuration

10. 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
endodontic failures
•
There may be evidence of
development of
new lesions :
Periapical,
Periodontal,
Nonendodontic
Or evaluation of the healing / progress of the treatment

12. LARGE PERI APICAL LESION
ENDODONTIC THERAPY
LESION DECREASES IN SIZE
LESION REMAINS SAME
LESION INCREASES IN SIZE
PERIODIC RECALL
RETREATMENT / RETREATMENT +
APICAL SURGERY

16. RADIOGRAPHIC SEQUENCE
I. Diagnostic :
The number of films used would depend upon the diagnostic
difficulty.
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

19. Angulation:
The most accurate radiographs are made using the paralleling
technique

20. Advantages :
Less distortion and more clarity
Reproducibility of film and cone placement [ using the XCP ]

21. 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

23. II. WORKING FILMS
These are the films which are used during the treatment
procedure.
Not essentially given to the patient for a record
These include
 Working length radiograph
 Master cone
 During obturation [ intermediate ]

24. 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.
 D>E>F

25. III. Obturation
Similar
basic principles as those required for diagnostic
radiographs.
But after obturation it is advisable to take atleast two
radiographs at different angulations to visualize any missed
canals

27. Extrusion of obturation
material
Obturation short of apex

28. Normal findings in x-rays
• Teeth
– dentin and enamel have different shades
• due to variation in mineralization
– radiopacity: enamel > dentin > pulp
– cemento-enamel junction should be recognized
• Periodontium
– 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

29.  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.

30. 
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.

31. The radiographic description of any lesion can give us
indications of:
 Tissue of origin
 Biological behavior
 Prognosis
 Treatment concerns
 Diagnosis or a Differential Diagnosis

32. A radiograph helps in describing the lesion’s

Size

Shape

Location

Density

Borders

Effect on adjacent structures

33. Shape
• Regular
• Irregular shape

34. Location
 Localized or generalized
 Unilateral or bilateral

36. 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.

39. Density
Radiopaque
Radiolucent

40. Mixed density:

41. Effect on adjacent structures
• Resorption
• Displacement
[Space occupying lesions displace other structures]
• Destruction
• Remodeling
•
Expansion

42. Displacement of roots
Resorption of roots

43. Remodelling
Expansion

44.  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.

45. Initial / immature phase of
Periapical cemental dysplasia
Mature phase of Periapical
cemental dysplasia

46.  These radiolucencies can be differentiated from pathologic
conditions by exposures at different angulations and by
pulp-testing procedures.
 Radiolucencies not associated with the root apex will move
or be projected away from the apex by varying the
angulation

47. • Other anatomic radiolucencies that must be differentiated from
periradicular pathoses are
 Mental Foramen
 Lingual Foramen
 Submandibular Fossa
 Nutrient Canals
 Median Palatal Suture
 Incisive Canal Foramen
 Nasal Cavity
 Mandibular Canal
 Maxillary Sinus

48. Differential diagnosis
Endodontic lesions
Radiolucent lesions :
1. Apical /radicular lamina dura is absent
2. A hanging drop of oil shape . Though a lesion ca be of
any shape
3. Radiolucency stays at the apex regardless of change in
the angulation.
4. The cause for pulp necrosis is ,in most cases ,evident

51. Radiopaque lesions
Condensing / sclerosing osteitis

52. Non odontogenic lesions

53. (Idiopathic) Osteosclerosis

54. Special Techniques :
Bitewing Projections : Useful in diagnosing dental caries
Especially the relation ship of the alveolar bone to the dental
caries [ proximal lesions]

55. CONE SHIFT TECHNIQUE
SLOB RULE

56. 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.

57. Important considerations:
Film selection
Film Holders
Film Placement
Cone alignment

58. Latest Radiographic Devices
Digital Radiography

59. Micro Computed Tomography [Micro CT]
Cone beam CT