LATEST METHODS

1. Radiographic Aids In
Diagnosis of
Periodontal Diseases
SHIVANGANI ARYA
JR-III
DEPARTMENT OF PERIODONTOLOGY
FODS,KGMU,LUCKNOW

2. HISTORY

3. Discovery of X-Rays - November 8th , 1895
Wilhelm Conrad Roentgen
(1845 – 1923)
Forms of tube used by Roentgen in 1895–1896 for the
production of X rays.

4. First Dental Radiograph – 12th January,
1896
Dr. Otto Walkoff
(1860 – 1934)

5. First Intraoral Dental Radiograph – Early
1896
Dr. Edmund Kells
(1856 – 1928)

6. DENTAL RADIOGRAPHS
 The radiograph is a valuable aid in the:
Diagnosis of periodontal diseases
Determination of the prognosis
Evaluation of the outcome of treatment
 However radiograph is an adjunct to the clinical
examination, not a substitute for it.
 The radiograph reveals alteration in calcified tissues.
 It does not reveals current cellular activity but shows
effects of past cellular experience on the bone & roots.

8. INTRAORAL PERIAPICAL RADIOGRAPHS
Paralleling technique
• Also called as “right angle” or “long cone
technique”.
• X-ray film is placed parallel to long axis of
tooth and central ray of x-ray beam is directed
at right angle to teeth & film.
• Most accurately projects the alveolar bone and
the CEJ
( Fitzgerald GM :Dental radiography IV 1950)

9. INTRA ORAL PERIAPICAL
RADIOGRAPHS
• Bisecting angle technique
• Central ray is directed at right angles to a plane
bisecting the angle between long axis of teeth &
film.
• Makes the bone margin appear more closer to
the crown.

10. Prichard(1972) established the following four
criteria to determine adequate angulation of
periapical radiographs:
1. The radiograph should show the tips of molar cusps with little or none of
the occlusal surface showing.
2. Enamel caps and pulp chambers should be distinct.
3. Interproximal spaces should be open.
4. Proximal contacts should not overlap unless teeth are out of line
anatomically.
(Prichard JF: advanced periodontal disease: surgical and prosthetic management,ed 2,
Philadelphia 1968)

11. BITEWING RADIOGRAPHS
 Records the coronal part of upper & lower
dentition along with periodontium.
USES
1)To study height & contour of interdental
alveolar bone.
(2)To detect interproximal calculus.
(3)To detect periodontal changes
(4) In pediatric patients
 Horizontal bitewing radiographs
useful for proximal caries detection
limited use in periodontal treatment and
treatment planning if bone loss is advanced

12. VERTICAL BITEWING RADIOGRAPHS
 Vertical bitewing films usually are used
when the patient has moderate to
extensive alveolar bone loss.
 Orienting the length of the film vertically
increases the likelihood that the residual
alveolar crests in the maxilla and the
mandible will be recorded on the
radiograph.

13. EXTRAORAL PERIAPICAL RADIOGRAPH
 (Newman And Friedman 2003)
Limitations with intraoral periapical radiographic imaging:
 Advancing age
 Anatomical difficulties like large tongue, shallow palate, restricted mouth
opening,
 Neurological difficulties, and size of radiographic sensor
Chen et al in 2007 developed
a
sensor beam alignment aiming
device for performing
radiographs using this
technique

14. OCCLUSAL RADIOGRAPHS
 Intraoral occlusal radiographs enable viewing of a
relatively large segment of dental arch.
USES
 To precisely locate roots and supernumerary, unerupted,
and impacted teeth.
 To localize foreign bodies in the jaws and stones in the
ducts of sublingual and submandibular glands
 To demonstrate and evaluate the integrity of the anterior,
medial, and lateral outlines of the maxillary sinus
 To aid in the examination of patients with trismus, who
can open their mouths only a few millimeters;
 This condition precludes intraoral radiography, which
may be impossible or at least extremely painful for the
patient

15. ANALOG TWO DIMENSIONAL IMAGING
TECHNIQUES
TECHNIQUE IMPLICATIONS
PERIAPICAL RADIOGRAPHS Asses root apex and severe bone loss
HORIZONTAL BITEWING Detect bone height along tooth root
VERTICAL BITEWING Assess moderate to severe bone loss
(Hausmann E. A contemporary perspective on techniques for the clinical assessment of alveolar bone. J
Periodontol. 1990;61:149–56)
(Jeffcoat MK, Wang IC, Reddy MS. Radiographic diagnosis in periodontics. Periodontol
2000. 1995;7:54–68 )

16. LIMITATIONS OF RADIOGRAPHS
 Conventional radiographs are specific but lack
sensitivity
• More than 30% of bone mass at alveolar crest must be
lost to be recognized on radiographs.
• Radiographs provide a 2-dimensional view of a 3-
dimensional image.
• Provides only information about inter proximal bone
level.
• Radiographs do not demonstrate soft tissue to hard tissue
relationship hence no information about depth of soft
tissue pocket.

17. NORMAL INTERDENTAL BONE
• Radiographic evaluation of bone changes in periodontal
diseases is based mainly on appearance of interdental
bone , because the relatively dense root structure
obscures the facial and lingual bony plates.
• The interdental septum normally presents a thin
radiopaque border that is adjacent to the PDL and at
alveolar crest, termed as Lamina dura.
• Because the lamina dura represents the cortical bone
lining the tooth socket, the shape and position of the root
and changes in the angulation of the x-ray beam produce
considerable variations in its appearance.
(Manson JD; The lamina dura 1963)

18. NORMAL INTERDENTAL BONE
 The width and shape of the interdental bone and
the angle of the crest normally vary according to
the convexity of the proximal tooth surfaces and
the level of the cementoenamel junction (CEJ) of
the approximating teeth.
(Ritchey B, Orban B: The crest of interdental
septa,J periodontal 1953)
 The facio-lingual diameter of the bone is related
to the width of proximal root surface.

19. BONE DESTRUCTION IN
PERIODONTAL DISEASE
 Early destructive changes of bone that do not remove sufficient
mineralized tissue cannot be captured on radiographs.
( Bender IB,Seltzer S: 1961)
 Therefore slight radiographic changes of the periodontal tissues suggest
that the disease has progressed beyond its earliest stages.
 The earliest signs of periodontal disease must be detected clinically

20. BONE LOSS
 The radiographic image tends to underestimate the severity of bone loss.
(Rees TD et al 1962)
 The difference between the alveolar crest height and the radiographic
appearance ranges from 0 to 1.6 mm, mostly accounted for by x-ray
angulation.
(Regan JE,Mitchell DF 1962)

21. BONE LOSS
 Radiographs are an indirect method for determining the amount of bone loss
in periodontal disease.
 They image the amount of remaining bone rather than the amount lost.
 The amount of bone lost is estimated to be the difference between the
physiologic bone level and the height of the remaining bone.
 A distance of 2 mm between CEJ and alveolar crest reflects normal
periodontium; this distance may be greater in older patients.
(Greenstein G, Polson A, Iker H, et al: Associations between crestal lamina
dura and periodontal status. J Periodontol 52(7):362–366, 1981).
(Hausmann E, Allen K, Clerehugh V: What alveolar crest level on a bite-wing
radiograph represents bone loss? J Periodontol 62:570, 1991).

22. PATTERN OF BONE DESTRUCTION
 In periodontal disease the interdental bone
undergoes changes that affect
• the lamina dura
• crestal radiodensity
• size and shape of the medullary spaces
• height and contour of the bone.
 Height of interdental bone may be reduced,
with the crest perpendicular to the long axis of
the adjacent teeth (horizontal bone loss) or
angular or arcuate defects (angular, or
vertical, bone loss) could form.

23. Generalized horizontal bone loss.

24. PATTERN OF BONE
DESTRUCTION
 Radiographs do not indicate the internal
morphology or depth of craterlike defects.
 Also, radiographs do not reveal the extent of
involvement on the facial and lingual surfaces.
 In most cases, it can be assumed that bone losses
seen interdentally continue in either the facial or
the lingual aspect, creating a troughlike lesion.
 A reduction of only 0.5 to 1.0 mm in the thickness
of the cortical plate is sufficient to permit
radiographic visualization of the destruction of the
inner cancellous trabeculae. (importance: crater-
like defects)
Interdental lesion that extends to the facial or
lingual surfaces in a troughlike manner.

25. Radiographic Appearance of Periodontal
Disease
PERIODONTITIS
 Fuzziness and disruption of lamina dura
• Crestal cortication continuity is the earliest radiographic change in
periodontitis and results from bone resorption activated by
extension of gingival inflammation into the periodontal bone.
• Depicting these early changes depends greatly on the radiographic
technique, as well as on anatomic variations (thickness and density
of interdental bone, position of adjoining teeth).
• The presence of an intact crestal lamina dura may be an indicator of
periodontal health, whereas its absence lacks diagnostic relevance
(Armitage G: Periodontal diseases: diagnosis. Ann Periodontol 1:37, 1996.)
( Bragger I: Radiographic diagnosis of periodontal disease progression. Curr Opin
Periodontol 3:59–67, 1996. )

26.  Continued periodontal bone loss and
widening of the periodontal space
results in a wedge-shaped radiolucency
at the mesial or distal aspect of the
crest.
Fuzziness and a break in the
continuity of the lamina dura
at the crest of the bone distal
to the central incisor . There
are wedge-shaped radiolucent
areas at the crest of the other
interdental bone.

27.  Subsequently, the destructive process
extends across the alveolar crest, thus
reducing the height of the interdental
bone.
Radiolucent projections from the crest into the
interdental bone indicate extension of destructive
processes. D, Severe bone loss.

28. INTERDENTAL CRATERS
 Interdental craters are seen as irregular areas of reduced density on the
alveolar bone crests. ( Ree 1982)
 Craters are generally not sharply demarcated but gradually blend with the rest
of the bone.
Conventional radiographs do not accurately depict the morphology or depth of
interdental craters, which sometimes appear as vertical defects.

29. FURCATION INVOLVEMENT
 Definitive diagnosis of furcation involvement is
made by clinical examination, which includes
careful probing with a specially designed probe
(e.g., Nabers).
 Radiographs are helpful, but root superimposition,
caused by anatomic variations and/or improper
technique, can obscure radiographic representation
of furcation involvement.
A, Furcation involvement indicated by triangular radiolucency in bifurcation
area of mandibular first molar. The second molar presents only a slight
thickening of the periodontal space in the bifurcation area. B, Same area as A,
different angulation. The triangular radiolucency in the bifurcation of the first
molar is obliterated, and involvement of the second molar bifurcation is
apparent.

30. FURCATION INVOLVEMENT
 To assist in the radiographic detection of furcation
involvement, the following diagnostic criteria are
suggested:
1. The slightest radiographic change in the furcation area
should be investigated clinically, especially if there is bone
loss on adjacent roots.
2. Diminished radiodensity in the furcation area in which
outlines of bony trabeculae are visible suggests furcation
involvement.
3. Whenever there is marked bone loss in relation to a
single molar root, it may be assumed that the furcation is
also involved.

31. PERIODONTAL ABSCESS
 The typical radiographic appearance of the periodontal abscess is
a discrete area of radiolucency along the lateral aspect of the root.
However, the radiographic picture is often not characteristic. This
can be due to the following:
1. The stage of the lesion.
2. The extent of bone destruction and the morphologic changes of the
bone.
3. The location of the abscess.

32. Figure 31-18 Radiolucent area on lateral aspect of root with chronic periodontal abscess.
Figure 31-19 Typical radiographic appearance of periodontal abscess on right central
incisor.
Chronic periodontal abscess.
A, Periodontal abscess in the
left maxillary first premolar
area. B, Extensive bone
destruction on the mesial
surface of the first premolar.
Gutta-percha point traces to
the root apex.

33. LOCALIZED AGGRESSIVE
PERIODONTITIS
 Initially, bone loss in the maxillary and mandibular incisor and/or first
molar areas, usually bilaterally, resulting in vertical, arc like destructive
patterns
 As the disease progresses, loss of alveolar bone may become generalized
but remains less pronounced in the premolar areas.

34. Localized aggressive periodontitis.
The accentuated bone destruction in the anterior and first
molar areas is considered to be characteristic of this
disease.

35. TRAUMA FROM OCCLUSION
 Trauma from occlusion can produce radiographically
detectable changes
• in the thickness of the lamina dura
• morphology of the alveolar crest
• width of the PDL space
• density of the surrounding cancellous bone.
(Burgett FG: from occlusion. Periodontal concerns.
Dent Clin North Am 39:301–311, 1995 )
Widened periodontal space
caused by trauma from
occlusion. Note the increased
density of the surrounding
bone caused by new bone
formation in response to
increased occlusal forces.

36. TRAUMA FROM OCCLUSION
 The injury phase of trauma from occlusion produces a loss of the lamina dura that
may be noted in apices, furcations, and marginal areas. This loss of lamina dura
results in widening of the PDL space.
 The repair phase of trauma from occlusion results in an attempt to strengthen the
periodontal structures to better support the increased loads.
 Radiographically, this is manifested by a widening of the PDL space, which may
be generalized or localized.

37. TRAUMA FROM OCCLUSION
 More advanced traumatic lesions may result in deep angular bone loss,
which, when combined with marginal inflammation, may lead to intrabony
pocket formation.
 In terminal stages, these lesions extend around the root apex, producing a
wide, radiolucent periapical image (cavernous lesions).

38. EXTRAORAL RADIOGRAPHS
 Extraoral radiographs are taken
when large areas of the skull or
jaw must be examined
 when patients are unable to
open their mouths for film
placement.
 Useful for evaluating large areas
of the skull and jaws but are not
adequate for detection of subtle
changes such as the early stages
of dental caries or periodontal
disease.

39. LIMITATIONS OF OPG
 Image distortion
 Lingual structures would be projected higher than buccal
surfaces.
 Use of screen film combination results in less details than
intra oral images
 Production of ghost images
 It can be used as a alternative for intra oral full mouth series
when combined with bite wing radiographs

40. Tugnait et al. 2000,2005
 The periodontal structures of interest noted on periapical radiographs are
also noted on panoramic radiographs.
 The radiographic features of interest on a panoramic radiograph
supplemented when necessary by a small number of intra-oral views, is
sufficient for the management of periodontal diseases.
Pepallasi EA et al 2000
 Panoramic radiographs may not reveal alveolar bony defects as
accurately as periapical radiographs.

41. ADVANCED 2D IMAGING TECHNIQUES
The limitations of traditional 2D imaging techniques could be
overcome with the evolution of advanced 2D imaging techniques.
 Xeroradiography
 Stereoscopy
 Scanography
 I125 absorptiometry
 Nuclear medicine.
(Takagi S, Chow LC, Brown WE, Dobbyn RC, Kuriyama M. Application of an x-ray image magnifier
to the microradiography of dental specimens. J Dent Res. 1985;64:866–9).
(Lopez J., Jr Xeroradiography in dentistry. J Am Dent Assoc. 1976;92:106–10).
(White SC, Pharaoh MJ. 5th ed. St. Louis, Missouri: Mosby Publication; 2004. Oral Radiology
Principles and Interpretation; pp. 248–50).

42. ADVANCED 2D IMAGING TECHNIQUES
TECHNIQUES IMPLICATIONS
XERORADIOGRAPHY To asses osseous repair after periodontal
surgery
(Lopez J., Jr Xeroradiography in dentistry. J Am
Dent Assoc. 1976)
I125 ABSORPTIOMETRY Mineral content of alveolar bone
(Hausmann E, Ortman LF, McHenry K, Fallon J
Periodontol. 1982)
SINGLE PHOTON
ABSORPTIOMETRY
Total thickness of alveolar ridge both soft and
hard tissues
DUAL PHOTON
ABSORPTIOMETRY
Determines the bone mass
NUCLEAR MEDICINE Detects alteration in bone metabolism
(Matteson SR, Deahl ST, Alder ME, Nummikoski
PV. Advanced imaging methods. Crit Rev Oral
Biol Med. 1996)

43. XERORADIOGRAPHY
 Xeroradiography is a promising imaging technique first introduced
by Carlson in 1937.
 In 1963, Stronezak first used it in dentistry.
 It accomplishes the property of edge enhancement by which small
structures and areas of minimal density differences are better
visualized.
 it is an excellent aid in evaluating initial osseous changes,
assessment of osseous repair after periodontal therapy, and to clearly
visualize the crestal heights.
(Lopez J., Jr Xeroradiography in dentistry. J Am Dent
Assoc. 1976;92:106–10)

44. I125 ABSORPTIOMETRY
 was introduced into dentistry by Hausmann et al. in 1962.
 In 1982 Ortman used this method to measure the mineral content of
alveolar bone.
 It is the most sensitive technique for analyzing periodontal bone changes
and can be used as a standard for comparing the sensitivity of other
techniques.
 Other variants of this technique include single photon absorptiometry that
measures the total thickness of the alveolar ridge (hard and soft tissue)
and dual photon absorptiometry that determines the bone mass.
(Hausmann E, Ortman LF, McHenry K, Fallon J. Relationship between alveolar bone measured
by 125I absorptiometry with analysis of standardized radiographs: 1. Magiscan. J
Periodontol. 1982;53:307–10)

45. NUCLEAR MEDICINE
 Nuclear medicine colloquially termed “bone scanning” is used to study
alterations in bone metabolism using radio labeled bone seeking
radiopharmaceutical like 99 m-technitium.
( Matteson SR, Deahl ST, Alder ME, Nummikoski PV. Advanced imaging methods. Crit
Rev Oral Biol Med. 1996;7:346–95).
 Nuclear medicine depicts changes that indicate bony metastases, primary
bone tumors, metabolic bone diseases, and stress fractures.
( Bell EG. Nuclear medicine and skeletal disease. Hosp Pract. 1972;8:49–60.)
( Jacobsson S, Hollender L, Lindberg S, Larsson A. Chronic sclerosing osteomyelitis of the
mandible. Scintigraphic and radiographic findings. Oral Surg Oral Med Oral
Pathol. 1978;45:167–74).
( Mettler FA, Guiberteau MJ. New York: Grune and Stratton; 1983. Essentials of Nuclear
Medicine Imaging; pp. 214–47.)

46. NUCLEAR MEDICINE
Nuclear medicine is useful in dentistry for the early detection of
periapical pathologies and growth disorders
(Garcia DA, Jansons D, Kapur KK. Bone-imaging and semiconductor probe measurements of technetium-
99m-polyphosphate in the detection of periapical pathology in the dog. Arch Oral Biol. 1976;21:167–74.)
( Donoff RB, Jeffcoat MK, Kaplan ML. Use of a miniaturized detector in facial bone scanning. Int J Oral
Surg. 1978;7:482–7)
(Kaban LB, Cisneros GJ, Heyman S, Treves S. Assessment of mandibular growth by skeletal scintigraphy. J
Oral Maxillofac Surg. 1982;40:18–22).
( Cisneros GJ, Jeffcoat MK, Kaban LB. Bone-seeking radiopharmaceutical uptake as an indicator of
mandibular growth in rats. Angle Orthod. 1985;55:336–44.)
Nuclear medicine has three categories of imaging devices: Those used
for planar nuclear imaging, single-photon emission computed
tomography (SPECT), and for positron emission tomography (PET).

47. PLANAR NUCLEAR IMAGING
This technique efficiently images large anatomical areas from a
wide variety of directions.
 It is used to view areas of the alveolar process in the laboratory
and clinical studies of periodontitis.
(Garcia DA, Sullivan TM, Jungman C, O’Neil DM. An experimental evaluation of endodontic
procedures and filling materials. Oral Surg Oral Med Oral Pathol. 1981;52:641–7)
(Jeffcoat MK, Kaplan ML, Weinstein M, Goldhaber P. Semiconductor probe measurements in
beagle pups during deciduous tooth development. J Dent Res. 1978;57:743–7)
(Kaplan ML, Davis MA, Aschaffenburg PH, Adelstein SJ, Goldhaber P. Clinical, radiographic and
scintigraphic findings in experimental periodontal disease in dogs. Arch Oral Biol. 1978;23:273–8)
 SPECT is an enhancement of planar imaging with improved
image resolution.
 PET: Clinical applications of PET scanning include cardiac
imaging and tumor diagnosis.

48. SPECIALIZED TECHNIQUES
 Introduction of digital radiography in dentistry
Early detection
Quantitative assessment
3 D imaging
applications with
meaningful diagnostic
utility

49. DIGITAL RADIOGRAPHY
 Digital radiography is a superior alternative for film based imaging
Digital in digital radiography means numeric format of image content as
well as its discreteness
 Images are numeric and discrete in two ways –
• Spatial distribution of picture elements (pixels)
• In terms of different shades of gray of each of pixels
DIGITAL IMAGE
Collections of individual pixels organized in a matrix of rows and
columns

50. DIGITAL RADIOGRAPHY
 Direct Method
Uses a Charge Couple Device (CCD)
or CMOS sensor linked with fiberoptic
or other wires to computer system
CCD receptor is placed intraorally as
traditional films , images appear on a
computer screen which can be printed
or stored
 Indirect Method
This method uses a phosphor
luminescence plate, which is a
flexible film like sensor placed
intraorally & exposed to
conventional x-ray tube.
A laser scanner reads the exposed
plates & reveals digital image data.
a. F speed film, b. phosphor plate, c. CCD sensor,
d. CMOS sensor

51. DIRECT TECHNIQUE INDIRECT TECHNIQUE

52. ADVANTAGES OF DIGITAL IMAGING
1.The elimination of chemical processing
2.Shorter exposure to display time
3.Imaging processing can be used to enhance the perceived quality .
4.The software offers a variety of measurement tools
5.One of the key features is the ready availability of the image.

53. DISADVANTAGES
 Familiarity with digital nature of images and understanding of
principles of image manipulation is required
 Lack of infection control.
 Patient discomfort during placement.
 As image can be easily manipulated, it can be misused in legal
proceedings.
 Grossly overexposed or underexposed images cannot be corrected

54. RADIOVISIOGRAPHY
(RVG)
 Duret F et al (1988)
 Based on use of CCD
Radio – X-ray generator connected to sensor
Visio – storage of incoming signals during exposure and
conversion to gray levels
Graphy – digital mass storage unit – connected to various
video printout devices
latest version
 Trophy has released a wireless version of their RVG
intraoral sensor named the RVG 6500.

55.  A.R. Talaiepour et al in 2005
evaluated the accuracy of RadioVisioGraphy (RVG) in the linear
measurement of interproximal bone loss in intrabony defects.
Comparison between RVG measures and intrasurgical estimates were
performed in 56 teeth with intrabony defects
The radiographic measurements overestimated interproximal bone loss
as compared to the intrasurgical measurements

56. DIAGNOSTIC EFFICACY OF DIGITAL
IMAGING WITH REGARD TO PERIODONTAL
LESIONS
 Nair et al. 2000 investigated the accuracy of alveolar crestal bone
detection utilizing Ektaspeed Plus film, Sidexis direct digital images,
and brightness-enhanced digital images. No significant differences were
found
 Wallace et al 2004 Demonstrated that E film displayed the highest
sensitivity and specificity followed by PSP and CCD images when
observers were able to adjust digital image contrast and brightness
enhancements.

57.  The main difficulty encountered during radiographic
interpretation is demarcating the pathology from the normal
anatomic background.
 The critical component of interpretation is the elimination of
irrelevant structures (noise). This was made possible with the
emergence of subtraction radiography.

58. DIGITAL SUBTRACTION RADIOGRAPHY
 Zeidses des Plantes (1935) : 1st demonstrated use of subtraction imaging
Depends up on conversion of serial radiographs into digital images.
The serially obtained digital images are superimposed & image intensities of
corresponding pixels are subtracted
If change has occurred
 The brighter area represents gain
 Darker area represents loss

59. This technique facilitates both qualitative &
quantitative visualization of even minor density
changes in bone by removing the unchanged anatomic
structures from image
Application of digital subtraction radiography for detection and quantification
of periodontal bone healing. A, Baseline image. B, Standardized l-year follow-up
image. C, Subtraction image showing increase in bone (arrow).

60.  Ortmann (1994)- 5% of bone loss can be detected.
 Diagnostic subtraction radiography (DSR) can be used for enhanced
detection of crestal or periapical bone density changes and to
evaluate caries progression

61. COMPUTER ASISTED DENSITROMETRIC
IMAGE ANALYSIS SYSTEM
 Introduced by Urs Brägger et al 1988
A video camera measures the light transmitted through the a radiograph
Signal are converted to grey scale images
Camera is interfaced with computer and image processor for storage
and mathematic manipulation of image
Offers an objective method for studying alveolar bone changes
quantitatively
High degree of sensitivity ,accuracy and reproducibility

62.  Urs Brägger et al in 1988
CADIA was more sensitive than subtraction radiography
CADIA was capable of assessing differences in remodeling activity over 4–6
weeks after periodontal surgery
Objective method to quantify alveolar bone density
 Deas et al 1991
on monitoring the relationship of CALs and CADIA, found that prevalence of
progressive lesions as detected by radiograph is higher than previous accepted data.
CADIA is still used in research purposes for detecting quantitatively the alveolar
bone density

63. EXTRAORAL DIGITAL IMAGING

64. CONVENTIONAL TOMOGRAPHY
 Designed to image a slice or plane of tissue
 Accomplished by blurring the images lying outside the plane of
interest
 It consists of an x ray tube and radiographic film rigidly connected
which moves about a fixed axis and fulcrum
 As exposure begins tube and film move in opposite direction
simultaneously .
 Objects located with in the fulcrum remain in fixed positions and
are viewed clearly

65. CONVENTIONAL TOMOGRAPHY
 Used less frequently with the introduction of: MRI , CT and Cone beam
imaging
 OPG is a variant of conventional Tomography

66. COMPUTED
TOMOGRAPHY
 Godfrey Hounsfield and Allan MacLeod
Cormack (1979) shared Nobel prize
Consists of a x ray tube emitting finely collimated
x ray beam directed through the patient to a series of
scintillating detectors or ionizing chambers
Detectors form a continuous ring and x-ray tube
moves in a circle with in the ring
Patients lie stationary and x ray tube rotates one
turn .then the table will move 1 to 5 mm to next scan

67. HELICAL CT
 Introduced in 1989
 The gantry containing x ray tube and
detectors continuously revolve around
the patient ,where as patients table
advances through the gantry.
 Result is acquisition of a continuous
helix of data.
 DETECTORS
 Gas filled ion chambers -xenon
 Solid state detectors- cadmium
tungstate

68. Computer algorithms use photon counts to construct digital images
 Images are displayed in individual blocks -----VOXELS
 Each square of the image is matrix----PIXELS
 Each pixel is assigned a CT number representing tissue density
 CT number HOUNSFIELD units
Range -1000 to 1000
CT IMAGE CONSTRUCTION

69.  ADVANTAGES
Eliminates superimposition of images of structures outside area of
interest
High contrast resolution – differences between tissues that differ in
density < 1% - can be distinguished
Images can be viewed in axial coronal and sagittal planes

70.  Naito T et al. 1998, Pistorius A et al. 2001.
 Used Computed tomography (CT) in studies in relation to periodontal
defects.
 CT does not offer any favourable cost benefit, dose exposure or
therapeutic yield advantage in periodontal practice and is unlikely to find
a routine

71. CONE BEAM COMPUTED TOMOGRPHY
Developed in 1982 for angiography
Utilizes cone shaped source of ionizing radiation & 2D area detector fixed
on a rotating gantry .
Multiple sequential images are produced in one scan
• Rotates 360° around the
head
• Scan time typically < 1
minute

72. CONE BEAM COMPUTED TOMOGRPHY
 Image acquisition involves a Rotational scan of a x-
ray source and reciprocating area detector moving
synchronously around patients head
• Many exposures are made at fixed intervals to form
basic images.
• Software programs are used to reconstruct 3D images

73. INDICATIONS
 Evaluation of the jaw bones
 Implant placement and evaluation
 evaluation TMJ
 Bony & Soft tissue lesions
 Periodontal assessment
 Endodontic assessment
 Alveolar ridge resorption
 Orthodontic evaluation
 Airway assessment
 Need for 3D reconstructions

75. CT V/S CBCT
 Conventional CT scanners make use
of a fan-beam and provides a set of
consecutive slices of image
 Conventional CT makes use of a lie-
down machine with a large gantry.
 Greater contrast resolution & More
discrimination between different tissue
types (i.e. bone, teeth, and soft tissue
 Utilize a cone beam, which radiates
from the x-ray source in a cone shape,
encompassing a large volume with a
single rotation.
 a sitting-up machine of smaller
dimensions
 Commonly used for hard tissue
 Ease of operation
 Dedicated to dental
 Both jaws can be imaged at the same
time
 Lower radiation burden
Artifacts arising from metal
restorations are more severe
using
conventional CT.
artifacts that arise from metallic
restorations are less severe

76. Kelly A. Misch et al . 2006
 Compared radiographs with CBCT
 Results: Three-dimensional capability of CBCT offers a significant advantage in
linear measurements for periodontal defect
 All defects can be detected and quantified.
Mol A and Balasundaram 2008
 Evaluated The NewTom 9000 CBCT scanner
 Results: Better diagnostic and quantitative information on periodontal bone
levels in three dimensions than conventional radiography can be obtained
 B. BEZAK et al 2010
 Assessed reliability and accuracy of Cone Beam Computed Tomography (CBCT)
against CAL
 CBCT measurement protocol is reliable.
 Accuracy of CBCT measurements correlates with CAL gold standard
measurements.

77. Walter C et al..2011-
 Suggests that cone-beam CT may provide detailed
information about furcation involvements in
patients with chronic periodontitis and so may
influence treatment planning decisions

78. SMALL VOLUME CT
 Form of CBCT
 utilizes small field high resolution
detector to generate high resolution 3D
volume
 Generally comparable to size of intraoral
radiographs
Van Daatselaar 2003
 based on comparison made between a
full CT geometry and a local CT
geometry.
 “local CT of dental structures appears to
be a promising diagnostic instrument.”

79. TACT-TUNED APERTURE CT
Based on the principles of tomosynthesis
Low cost, low dose ,3D Imaging system
Series of radiographs taken from different angles
Soft ware (work bench) stacks the basic images
and reconstruct in to multi planar images
Caries detection
Vertical root fracture
Helps to detect osseous defects around implants
Detection and localization of osseous changes in
crestal bone

80. DENTA SCAN
 Denta Scan is a unique computer
software program provides computed
tomographic (CT) imaging of the
 mandible and maxilla in three planes of
reference:
 axial, panoramic, and oblique sagittal

81. USES OF DENTA SCAN
 visualization of internal bone morphology in three dimensions ; precise
treatment planning
 In cross sectional view, observation regarding bone quality, density can be
made
 pre-operative planning of endosseous dental implants and subperiosteal
implants
 to visualize the bony structures preoperatively
 Denta scan CT provides information of the internal structures that cannot
even be gained by direct intra-operative visualization
the precise location of the mandibular canal
the location of the floor of the maxillary sinuses

82. MAGNETIC RESONANCE
IMAGING
 It does not involve the use of ionizing
radiation
 It involves the behaviour of protons in a
magnetic field.
 Hydrogen protons are used to create the MR
image.
 The image itself is another example of a
tomograph or sectional image that at first
glance resembles a CT
 Used for imaging intracranial and soft tissue
lesions

83. USES IN HEAD AND NECK REGION
 Assessment of intracranial lesions involving particularly the posterior
cranial fossa, the pituitary and the spinal cord.
 Investigation of the salivary glands
 Tumour staging
 Investigation of the TMJ to show both the bony and soft tissue
components
 Implant assessment

84. ULTRASONOGRAPHY
PRINCIPLE
 Scanners used for sonography generate electrical impulses that are
converted into ultra-high-frequency sound waves by a transducer.
 The most important component of the transducer is a thin piezoelectric
crystal or material made up of a great number of dipoles arranged in a
geometric pattern.
 The following Modes are in use :
 • A Mode Amplitude mode – not in use
 • B Mode Brightness Mode – Producing different echogenicity
 • TM Mode Motion mode – used in foetal
 • Time Motion ECG and Doppler study.

85. ULTRASONOGRAPHY
 Diagnostic ultrasound – the ultrasonic intensities used are typically 5 to 500
mW/cm2 and
it includes:
 Swellings in orofacial region
 Salivary glands disorders
 Periapical lesions
 Lymph nodes – benign/malignant
 Intraosseous lesions
 Temporomandibular disorders
 Primary lesions of the tongue

86. CONCLUSION
 Radiography must not be a substitute for clinical investigation
 X-rays as a component of periodic examinations cannot be condoned.
 Radiographic examination in clinical periodontology is only justified if
changes in treatment plans from those treatment plans developed on the
basis of clinical examination supplemented by any already available
radiographs are anticipated

87. CONCLUSION
 Advanced imaging systems like CTs ,CBCTs, have enabled better
visualization of periodontal structures and pathologies in3D thus helping
in better diagnosis and treatment planning
 The cost factor and other technical difficulties have limited their clinical
utility but their utility as a research tool is unquestionable.
 In near future these imaging techniques will become routine diagnostic
tools.

88. THANK YOU