By Dr. Jyothish.k, GDC CALICUT

1. PRINCIPLES OF RADIOGRAPHIC
EXAMINATION

2. In the Land of 10,000 lakes,…

3. …we see the fish!

5. Liar, Liar!! Do Our Eyes Lie?

6. Radiographic interpretation as you do all other
aspects of evaluation – systematic and repetitive
NORMAL VS. ABNORMAL
•Anatomy (hard tissue, soft tissue)
•Variants (torus, root shape)
•Pathology ( decay, bone loss, disease

7.  VIEWING CONDITIONS:
 Ambient light in the viewing room should be reduced
 Intraoral radiographs should be mounted in a film
holder
 Light from the view box should be of equal intensity
across the viewing surface
 The size of the view box should accommodate the size
of the film
 An intense light source is essential for evaluating dark
regions of the film
 A magnifying glass allows a detailed examination of
small regions of the film

8.  2 basic approaches can be used:
1) Picture matching or ”Aunt Minnie” method
 This involves trying to match the radiographic image
with a mental picture or with a image in a favorite
textbook.
2) systematic and repetitive
 Step by step analysis of all the radiographic
characteristics of the abnormality and production of
a radiographic interpretation on the basis of these
findings.
 Helps to ensure recognition and collection of all the
information contained in the image and in turn
improves the accuracy.

9. • STEP;1
Localize The Abnormality

10. Localize The Abnormality
Localized or Generalized
• The anatomic location and limits of the abnormality should be
described. This information aids in starting to select various disease
categories.
• If an abnormal appearance affects all the osseous structures of the
maxillofacial region, Generalized disease mechanisms,
• Metabolic or
• Endocrine abnormalities of bone, are considered.
Localized
unilateral or bilateral.
• Variations of normal anatomy are more commonly bilateral.
• For instance, a bilateral mandibular radiolucency may indicate normal
anatomy, such as extensive submandibular gland fossa.

11. • Abnormal conditions are more commonly unilateral.
• For instance, fibrous dysplasia commonly is unilateral. This is not to
say that localized pathologic lesions cannot occur bilaterally in the
maxillofacial region.
• A few abnormalities, such as Paget’s disease and cherubism, are
always seen bilaterally in the jaws.
• when cherubism involves the mandible, the first region to be
involved is in the midramus region, and this is the mechanism behind
the anterior displacement of molars.

16. Position in the Jaws
• Identifying the exact location of the lesion in the maxillofacial
complex aids the diagnostic process in two ways:
• (1) It determines the epicenter
• (2) Some lesions tend to be found in specific locations.
• Epicenter - the point of origin assists in indicating the tissue types
that compose the abnormality in question.
• The epicenter can be estimated on the basis of the assumption that
the abnormality grew equally in every direction.
• This estimation may become less accurate with very large lesions or
lesions with ill-defined boundaries

17. If the epicenter is coronal to a tooth, the lesion probably is
composed of odontogenic epithelium
A, Cropped panoramic image of a lesion where the epicenter is
coronal to the unerupted mandibular first molar. B, Occlusal
projection providing a right-angle view of the same lesion

18. If it is above the inferior alveolar nerve canal (IAC), the likelihood is
greater that it is composed of odontogenic tissue
Panoramic image revealing a cystic ameloblastoma within the body of
the left mandible. The inferior alveolar nerve canal has been displaced
inferiorly to the inferior cortex (arrows), indicating that the lesion
started superior to the canal

19. If the epicenter is below the IAC, it is unlikely to be odontogenic
in origin
Cropped panoramic image displaying a lesion (developmental
salivary gland defect) below the inferior alveolar canal and thus
unlikely to be of odontogenic origin

20. If it originates within the IAC, the tissue of origin probably is
neural or vascular in nature
Lateral oblique view of the mandible revealing a lesion
within the inferior alveolar canal. The smooth fusiform
expansion of the canal indicates a neural lesion

21. If the epicenter is within the maxillary antrum, the lesion is not of
odontogenic tissue, as opposed to a lesion that has grown into the antrum
from the alveolar process of the maxilla
The lack of a peripheral cortex (arrows) on this retention pseudocyst
indicates that it originated in the sinus and not in the alveolar process.
Therefore, it is unlikely to be of odontogenic origin

22. • The probability of cartilaginous lesions and osteochondromas
occurring is greater in the condylar region.

23. • The other reason to establish the exact location of the lesion is that
particular abnormalities tend to be found in very specific locations.
Following are a few examples of this observation:
• The epicenters of central giant cell granulomas commonly are
located anterior to the first molars in the mandible and anterior to
the cuspid in the maxilla in young patients.
• Osteomyelitis occurs in the mandible and rarely in the maxilla.
• AOT
• Globulomaxillary cyst
• Stafne’s cyst vs ABC

26. • Single or Multifocal
• Establishing whether an abnormality is solitary or multifocal aids in
understanding the disease mechanism of the abnormality.
Additionally, the list of possible multifocal abnormalities in the jaws
is relatively short.
• Periapical cemental dysplasia,
• Keratocystic odontogenic tumors,
• Metastatic lesions,
• Multiple myeloma
• leukemic infiltrates.
Exceptions to all these points may occur occasionally. However, these
criteria may serve as a guide to an accurate interpretation

27. Cropped panoramic film revealing several small, punched-out
lesions of multiple myeloma (a few are indicated by arrows)
involving the body and ramus of the mandible

28. Size
•Finally, the size of the lesion is considered.
There are very few size restrictions for a
particular lesion, but the size may aid in the
differential diagnosis.
•differentiating between a dentigerous cyst
and a hyperplastic follicle

31. STEP 2: ASSESS THE PERIPHERY AND
SHAPE
Study the periphery of the lesion
2 types:
◦ Well defined
◦ Ill defined

32. WELL DEFINED BORDERS:
Punched out border
Sharp boundary no bone reaction
Analogous to punching a hole in a radiograph
Normal surrounding bone upto the edge of the hole

33. Corticated margin
• Thin
• Fairly uniform- Radiopaque line
• Reactive bone at the periphery of the lesion

34. Sclerotic margin
• Wide
• Non-uniform
• Radiopaque- Reactive bone
• Indicate- very slow rate of growth

35. Radiolucent borders
R.Opaque lesions may have soft tissue capsule
Seen in conjuction with corticated periphery

36. Ill- defined borders
Blending border
◦ Is ill defined because of gradual transition between
normal appearing bone trabeculae and abnormal
appearing trabeculae of the lesion .
◦ Example:
 Sclerosing osteitis
 Fibrous dysplasia

37. Invasive border
• Rapid growth / Malignant lesions
• Area of radiolucency with fewer or no trabeculae
• Represents marginal bone destruction
• Produces radiolucent fingerlike or bay-type extension at the
periphery
• Eg; Malignant lesions

38. Shape:
- Lesion may have a particular shape or it may be
irregular.
- Eg: a circular /fluid filled shape/ inflated balloon -
referred to as hydraulic is a characteristic of cyst.

39. Scalloped shape
•Series of contiguous arcs or semicircles- reflects the
mechanism of growth
•Provides a multilocular appearance
•Okc,Ameloblastoma

41. STEP 3 –ANALYSE THE INTERNAL STRUCTURE
Internal appearance of the lesion can be classified into three basic
categories:
- Totally radiolucent- cyst
- Totally radiopaque –osteomas
-Mixed radiolucent and radiopaque
Radiolucent Radiopaque Mixed (RL-RO)
Radiodensity

52. Fuzzy or irregular trabeculae.

57. STEP 4 – ANALYSE THE EFECTS OF THE LESION
OF SURROUNDING STRUCTURES
• Evaluating the effects of the lesion on the surrounding structures
allows the observer to infer its behavior which aids in identification
of the disease.
• But this requires the knowledge of the mechanisms of various
diseases.

58.  Teeth, lamina dura and periodontal space
 Displacement of the teeth is seen more commonly
with smaller growing space occupying lesions.
 Widening of the periodontal membrane space may
be seen with many diff kinds of abnormalities.
 Resorption of the teeth usually occurs with more
chronic or slowly growing process and may result
from chronic inflammation.

59.  Surrounding bone density and trabecular pattern
 The presence of reactive bone at periphery of a lesion, whether
corticated or sclerotic, usually signifies slow , benign growth and
possibly the ability to stimulate osteoblastic activity in the
surrounding bone.
 Inferior alveolar nerve canal and mental foramen
 Outer cortical bone and periosteal reactions

60. STEP 5; FORMULATE A RADIOGRAPHIC
INTERPRETATION
The preceding steps enable the observer to collect all
radiographic findings in an organized fashion.

62. Decision 1:
 The practitioner should determine whether the structure
of interest is a variation of normal or represents an
abnormality-crucial decision
Decision 2:
 If the area of interest is abnormal , the next step is to
decide whether the radiographic characteristics indicate
that the region of interest represents a developmental or
an aquired change.

63. Decision 3:
 If the abnormality is acquired the next step is to select the
most likely category of acquired abnormality: cysts,
benign tumors, malignant tumors, inflammatory lesions,
bone dysplasias, vascular abnormalities, metabolic
diseases, or physical changes such as fractures.
Decision 4:
 After analysing the images, the clinician must
decide in what way to proceed- further imaging
treatment biopsy or observation of the abnormality

67. THANK YOU