2. Periodontium refers to the tissues that invest
and support the tooth such as gingiva and
Normal anatomic structures of alveolar bone
includes lamina dura, alveolar crest and
periodontal ligament space.
Lamina dura: in health lamina dura appear as
dense radiopaque line around each root. It is a
radiographic representation of alveolar bone
3. Alveolar crest: healthy alveolar crest is located
1.5 to 2 mm apical to cemento enamel junctions
of adjacent tooth.
Shape and density of alveolar crest varies
between anterior and posterior tooth.
In anterior regions the alveolar crest appears
pointed and sharp ,normally very radiopaque.
In posterior regions appears flat ,smooth and
parallel to line between adjacent CEJ.
Slightly less radiopaque than that in anterior
4. Although these are normal features of healthy
periodontium , they are not always evident.
Their absence from radiograph does not
necessarily mean that periodontal disease is
Failure to see these features may be due to:
Normal anatomic variation in alveolar bone
density and shape.
8. Periodontal ligament space: The normal PDL
space appears as a thin radiolucent area
between root of the tooth and lamina dura.
It is continuous around root and slightly wider
around cervical portion of the root especially in
adolescents with erupting teeth.
10. Periodontal means around the tooth.
Periodontal diseases refers Group of diseases
that affects the tissues around the tooth.
They are set of conditions characterised by
inflammatory host response in periodontal
tissues may lead to localized or generalized
alterations in the soft tissues and bone
ultimately loss of tooth.
Periodontal diseases are classified into:
11. Gingival diseases are :
caused by trauma
Acute ulcerative gingivitis
Acute herpetic gingivo
12. Periodontal diseases:
Acute periodontal abscess
Early onset periodontitis:
13. Systemic or generalized conditions that affect the
14. The main radiographic projections used to
show the periodontal tissues include:
Bitewings: horizontal and vertical ,used
normally for posterior tooth.
Panoramic radiography: where there is
pocket area more than 5mm.
15. Radiographs play integral role in the assessment of
They provide information about the status of
periodontium that cannot be obtained clinically.
Radiographs are especially helpful in evaluation of
Amount of bone present
Condition of alveolar crest
Bone loss in the furcation areas
Width of PDL space
Local irritating factors that increase the risk of
Calculus and poorly contoured restorations
16. Root length and morphology
Crown to root ratio
Open interproximal contacts
position of maxillary sinus
Missing ,super numerory and
17. Limitations of the radiographs:
1.Radiographs provide a two dimensional
view of three dimensional situation. Because
the radiographic image fails to reveal
3dimensional picture bony defects
overlapped by higher bony walls may
2.Radiographs typically show lesser boneloss
than actually present.
3.Donot demonstrate soft tissue to hard
4.Bone level measured from CEJ ,their
reference point not valid in over eruption
,passive eruption and attrition.
18. Gingivitis is an inflammatory condition
confined to gingiva no significant changes
in underlying bone.
In periodontal diseases changes can be
Morphology of supporting alveolar
Changes to the internal density
Changes in Trabecular pattern
19. Changes in morphology of surrounding bone:
Become apparent as a result of loss of
interproximal bone and bone overlapping
the buccal and lingual aspect of tooth
Early bony changes : Appear as areas of
localized erosion of the interproximal
alveolar bone crest.
Anterior and posterior regions show loss
of normal sharp angles b/n lamina dura
and alveolar crest.
In early stages this angle may loss
normal cortical surface and appear round
21. As lesion progresses it may induce variety of
defects in morphology of alveolar bone.
The patterns of bone loss have been divided into:
Bone loss defined as a difference between the
present septal bone height and assumed normal
bone height for any particular patient.
Horizontal bone loss
Vertical bone loss
Inter dental craters
Buccal or lingual cortical plate bone loss
Furcation involvement in multi rooted
22. Horizontal bone loss: The CEJ of adjacent tooth
can be used as a plane of reference in
determining the pattern of bone loss present.
With horizontal bone loss occurs in a plane
parallel to the CMJ of adjacent tooth but
positioned apically more than couple of mms
Horizontal bone loss may be mild ,moderate
Mild: 1-2mm loss of supporting bone.
Moderate : greater than 2mm upto loss of half of
Severe: anything beyond half.
25. Vertical bony defects: Also called angular
Bone loss does not occur in plane parallel to
the CEJ of adjacent tooth.
It may be three walled, two walled, one walled.
Three wall defect: surrounded by 3bony
walls.Buccal and lingual cortical plates
Two wall defect: one of these plates has been
One wall defect: Both plates have been lost.
28. Inter dental craters: It is a two-walled
,through like depression that forms in the
crest in the interdental bone between
R/G : It presents as a bandlike or irregular
region of bone with less density at the crest
,immediately adjacent to more dense
normal bone apical to base of crater.
30. Buccal or lingual cortical plate loss:
Loss of cortical plate may occur alone or
associated with horizontal bone loss.
It is indicated by an increase in
radiolucency of the root near the alveolar
Shape is usually semi-circular shadow
with apex of R/L directed apically in
relation to tooth.
31. Furcation involvement in multi rooted tooth:
Furcation involvement describes the r/g
appearance of bone loss in the furcation area of
Most commonly seen on mandibular molars
,they can also seen on maxillary molars despite
the superimposed shadow of palatal root.
34. Distribution of bone loss:
Distribution is described as a localized
Localized : Bone loss occurs in isolated
Generalized: Bone loss occurs evenly
35. Severity of bone loss:
Classified as a :
Mild bone loss -crestal changes.
Moderate bone loss- Bone loss of 10-
Severe bone loss- Bone loss of 33% or
36. Changes to internal density and trabecular
pattern of bone:
Changes reflect either reduction or an increase
in bony structure.
The peripheral bone may appear : more R/L
Mixed r/l and r/o.
R/L: Loss of density and no of trabeculae.
Trabeculae are faint ,seen in acute phases.
R/O: Sclerotic bone reaction may appear r/o
because of deposition of bone.
37. Classification of periodontal diseases:
Based on amount of bone loss can be
ADA case type1
ADA case type2
ADA case type3
ADA case type4
38. ADA case type1: Gingivitis
No bone loss associated, no r/g
ADA case type2: Mild periodontitis
Bone loss is mild crestal changes.
ADA case type3: Moderate periodontitis
Bone loss is moderate,10 to 33%
Horizontal or vertical
ADA case type4: Advanced periodontitis
Bone loss is severe 33% or more
39. Other patterns of bone loss:
Acute periodontitis or Periodontal abscess: It is a
rapidly progressing, destructive lesion that
usually originates from deep periodontal
R/G: If lesion is acute no visible r/g changes.
In chronic cases R/L lesion appears
,often superimposed over the root of tooth.
41. Chronic periodontitis: Most common form
The main pathological features are:
Destruction of PDL fibers
Resorption of alveolar bone
Loss of epithelial attachment
Formation of pockets
42. R/G features of chronic periodontitis:
Loss of corticated interdental crestal margin
,the bone edges becomes irregular or blunted.
Widening of PDL space at the crestal margin.
Loss of normally sharp angle b/n crestal bone
and lamina dura.
Localized or generalized bone loss of alveolar
Loss of bone in furcation area of multi rooted
43. Associated complicating secondary factors:
Over hanging filling ledges
Lack of contact points
Over erupted and tipped tooth
Poor restoration contours
Perforation by pins and posts
47. Early onset juvenile periodontitis: This is
localized severe form of disease develops
R/G findings :
Severe vertical bone loss affecting 1st
molars and incisors.
Arch or saucer shaped defects.
Migration of incisors with diastema
Rapid rate of bone loss.
50. Dental conditions associated with periodontal
Occlusal trauma: traumatic occlusion causes
degenerative changes in response to occlusal
forces that is greater than physiologic tolorence.
R/G findings : increased width of PDL space.
Thickening of lamina dura.
Increase in number and size of
51. Tooth mobility : may due to occlusal trauma or
loss of bone support.
Affected tooth has single root ,socket may
develop hour-glass appearance.
Affected tooth has multi-rooted,it may show
widening of PDL space at the apices and
region of furcation.
These changes result when the tooth moves
about an axis of rotation at some mid point on
52. Open contacts: When mesial and distal surfaces
of adjacent tooth do not touch patient has a
This space is potential for entrapment of food
Trapped food debris may damage soft tissue
and induce localized inflammatory reaction
and contribute to development of localized
56. Evaluation of periodontal therapy:
Radiographs may show signs of
successful treatment of periodontal disease.
In some cases, there may be reformation of
interproximal cortex and sharp line angle
between the cortex and lamina dura.
The relatively R/L margins of bone that were
undergoing active resorption before treatment
may become more radiopaque after successful
Oral Radiology Principles and Interpretation-
Stuart C. White and Michael J.Pharoah-6th edition
Essentials of dental radiography and radiology-
Eric Whaites-3rd edition
Dental radiology principles and techniques-Joen
Iannucci Haring-2nd edition