Dr. Ahmed M. Adawy, Professor Emeritus, Dep. Oral & Maxillofacial Surgery. Former Dean, Faculty of Dental Medicine, Al-Azhar University. Conventional radiography may revel a variety of radiolucent legions in the mandible. Interpretation of such radiolucencies can be challenging either because the clinical presentation may be non specific or because the ;legion is detected incidentally. Further, interpretation may vary from one examiner to another. thus, systemic approach is necessary to diagnose the legion or at least provide a meaningful deferential diagnosis. This approach should focus on specific radiographic parameters. Initially, the legion should be placed in the category of either normal or abnormal. The presented parameters includes describing the legion in terms of: 1- Location, 2- Margins, 3- Size and shape, 4- Effect on surrounding structures. Obviously, however diagnosis of a legion should never be made exclusively on the bases of radiographic interpretation. Radiographic interpretation should be used along with clinical information and other tests to formulate a deferential diagnosis.

2. Dr. Ahmed M. Adawy
Professor Emeritus, Dep. Oral & Maxillofacial Surg.
Former Dean, Faculty of Dental Medicine
Al-Azhar University

3. Conventional radiography may reveal a variety of
intraosseous lesions in the mandible. These represent a
broad spectrum of odontogenic and non-odontogenic
lesions with a varying degree of malignant potential.
Mandibular lesions can be described as having either
a radiolucent, radiopaque, or mixed appearance. The
vast majority of jaw lesions (more than 80%) are
radiolucent (1)

4. Various mandibular lesions. Panoramic radiographs
Show radiolucent, radiopaque, or mixed appearance

5. Based on another classification, intraosseous lesions can
be classified as inflammatory lesions, cysts, benign
tumors, malignant neoplasms and osseous manifestations
of systemic conditions. Differentiation of these lesions
from normal anatomic structures of the jaws is of
particular importance and since a dentist might be the first
individual to diagnose these lesions, it is very important to
have a proper knowledge of the prevalence and
characteristics of these lesions for diagnosis and treatment
planning

6. Interpretation of radiolucent lesions of the mandible can
be challenging either because the clinical presentation may
be non-specific or because the lesion may be detected
incidentally (2). Further, interpretations may vary from
one examiner to another (3). Thus, systematic approach to
the evaluation of radiolucent jaw lesions is necessary to
diagnose the lesion or at least provide a meaningful
differential diagnosis. Such approach should focus on
specific radiographic parameters (4), which could allow
greater diagnostic accuracy, mainly in the case of lesions
of difficult radiographic interpretation

7. Location (5)
Certain lesions have a predilection for a particular site,
whereas others can occur anywhere in the jaw. Non-
odontogenic lesions usually have no specific relationship to
the dentition or can involve the bone around two or more
teeth, whereas odontogenic lesions typically involve only one
tooth or a specific part of the tooth. A tooth-related lesion
may also arise or persist at the site of a congenitally
absent or extracted tooth. A single periapical radiolucency
of an anterior mandibular tooth would suggest a diagnosis of
periapical inflammatory disease, while multiple periapical
radiolucencies would be more consistent with cemento-
osseous dysplasia

8. A B
C D
A- Single periapical lesion B- Multiple periapical lesions
C- At the site of extracted molar D- Paradental

9. The relative position of the lesion can also be extremely
helpful. Some lesions might be located around the tooth
root, around the crown and in the inter-radicular area,
whereas others might have no relation with teeth

10. Relationship of the lesion with respect to the inferior
alveolar canal indicates tissue types that compose the
lesion. Lesions above the canal are likely to be
odontogenic, whereas lesions below it are usually non-
odontogenic in nature. Lesions close to the inferior
alveolar canal would be suggestive of a neural origin
Lesion below the inferior
alveolar canal
Lesion within the inferior
alveolar canal.

11. Similarly, unilateral defects are more suggestive of a
disease process while bilateral symmetrical defects would
most likely represent normal (or variations of normal)
structures. If the abnormal appearance affects all the
structure of maxillofacial region, systemic disorders such
as metabolic or endocrine abnormality should be
considered.
Bilateral numerous
mandibular radiolucencies

12. Margins (5)
The margins can either be described as well-defined or
ill-defined. Well-defined margins usually represent
benign processes. They may have corticated margins,
a thin radio-opaque line around the periphery of the
defect (sclerotic margins), and a wider, non-uniform
radio-opaque periphery. A lesion with an ill-defined
(diffuse) border is suggestive of a lesion enlarging by
invading the surrounding bone, such as in aggressive
inflammatory or neoplastic pathology

13. Well-defined margin
Ill-defined margin

14. Measure the lesion with a ruler. If you must estimate, use
surrounding structures as guide. Measurements should
include the width and height in mm or cm
Small radiolucency
Large midline radiolucent lesion

15. The shape of the lesion (5) can provide pertinent clues for
diagnosis. Regular shapes like round, triangular and
rhomboid are mostly seen. Irregular shape like circular
or scalloped-multilocular appearance is sometimes
encountered. A unilocular, well-demarcated defect would be
most consistent with a slow proliferating benign process. A
multilocular radiolucent lesions with well-defined borders,
also referred to as honeycomb, soap-bubble, tennis racket or
scalloped pattern, with well-defined borders would be
highly suggestive of a benign yet aggressive process such as
an ameloblastoma, or odontogenic myxoma. Moth eaten
osteolytic pattern signals either an inflammatory condition,
such as chronic osteomyelitis or a primary or metastatic
malignant lesion

16. Unilocular radiolucency Multilocular, soap-bubble radiolucency
Moth eaten osteolytic pattern

17. Evaluating the effect of the lesion on the surrounding structures
is a good measure of the clinical behavior of the disease
process (6). Slow growing benign processes frequently result in
tooth displacement. Dentigerous cyst, for example, displace the
tooth apically. Chronic inflammatory processes would result in
tooth resorption rather than displacement. However, malignant
lesions also occasionally resorb teeth. Slow-growing lesions
often cause expansion with cortical bowing, while cortical
destruction denotes aggressive inflammatory or neoplastic
lesions. Presence of periosteal reaction is also suggestive of an
inflammatory or malignant aetiology. Some types of periosteal
reactions are quite specific, like the sunburst type in
osteosarcoma

18. Large radiolucent lesion involving
mandibular angle and ramus.
Note displacement of third molar
Large mandibular radiolucency.
Tooth resorption is clearly seen

19. Multilocular radiolucency. The
lesion causes expansion of
buccal and lingual plates
Mandibular lesion causing
destruction of the buccal cortex

20. Systematic radiographic interpretation should be started
by placing the “lesion” in the category of either normal or
abnormal. If the lesion is abnormal, then it is either
developmental or acquired. This step is followed by
adding a description to the disease process, such as
benign, malignant, slow-growing, inflammatory, or fibro-
osseous. Obviously, however, diagnosis of a lesion should
never be made exclusively on the basis of radiographic
interpretation. Appropriate radiographic interpretation
should be used along with clinical information and other
tests to formulate a differential diagnosis. The best way to
establish a definitive diagnosis is to perform a biopsy

22. 1. DelBalso AM. An approach to the diagnostic imaging of jaw lesions,
dental implants, and the temporomandibular joint. Radiol Clin North Am,
36: 855, 1998.
2. Dunfee BL, Sakai O, Pistey R, et al. Radiologic and pathologic
characteristics of benign and malignant lesions of the mandible.
Radiographics 26: 1751, 2006.
3. Stheeman SE, Mileman PA, Hof M van’t, et al. Room for improvement?
The accuracy of dental practitioners who diagnose bony pathoses with
radiographs. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 81: 251,
1996.
4. Mourshed F. An approach to the teaching of radiographic interpretation of
bone lesions. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 50: 92,
1980.
5 . Neyaz Z, Gadodia A, Gamanagatti S, et al. Radiographical approach to
Jaw lesions. Singapore Med J. 49: 165, 2008.
6 . Theodorou S, Theodorou D, Sartoris D. Imaging characteristics of
neoplasms and other lesions of the jaw bones Part 1. Odontogenic tumors
and tumor like lesions. J Clin Imaging. 31: 114, 2007.