RECENT ADVANCES
IN DIAGNOSTIC AIDS

INDIAN DENTAL ACADEMY
Leader in continuing dental education
www.indiandentalacademy.co...
Specialized radiographic techniques

www.indiandentalacademy.com
•
•
•
•

Digital subtraction radiography
Xeroradiography
Ultrasonography
Laser holography

www.indiandentalacademy.com
Digital subtraction radiography

www.indiandentalacademy.com
• Requires two different images and the
subtracted image is a composite of
these two images representing their
different d...
• Sensitive enough to detect a .12 mm
change in the cortical bone.
• The ability of this technique to detect
minute change...
Technique
• In DSR two standardized radiographs of
anatomical region are made with
identical exposure geometry at differen...
www.indiandentalacademy.com
• The first reference image is digitized
and converted to a exact positive image
by the computer and displayed on the
TV s...
• Any differences between the two
images will be shown on neutral gray
background as brighter or darker areas
depending on...
• By this process a radiograph is
converted to an array of points each of
which has a specific optical density.
• If each ...
• In clinical practice the two radiographs
are taken one after he other ,after some
time presuming some tissue changes
hav...
www.indiandentalacademy.com
Procedure
• Digitization
• To digitize a picture is taken using a
video camera
• Then computer digitizers place a grid
ove...
Limitations
• Diagnostic information can only be
obtained when orientation of the x ray
source,object and the image recept...
Overcoming the limitations
• Computer algorithms have been
developed for overcoming the variation
in density and contrast....
• Computer can be used to correct
distortion caused by film placement
• Reference points can be used to
superimpose sequen...
Applications
• Useful in diagnosis of periodontal and
carious lesions. (both of which are
characterized by insidious and s...
Applications
• Used for quantitative estimation of mass
or volume of a lesion. measurement
can be measured with the help o...
• Contrast enhancement with image in
color can detect small change in bone.

www.indiandentalacademy.com
• Useful in detection of small changes in
mandibular condyle position and
integrity of articular surfaces and or
remodelin...
• Assessment of failure of implant therapy
and progress of periodontal therapy.

www.indiandentalacademy.com
Image enhancement of mandibular
condyle through digital subtraction
• OOO 1987 ( south had et al )

www.indiandentalacadem...
Radiographic evaluation of the effect
of orthodontic retraction on the root of
the maxillary canine
• Perona and wenzel (d...
Digital subtraction radiography for
assessing alveolar bone
grafts:diagnostic accuracy and
sensitivity
• Maruko and Forbes...
Ultrasonography

www.indiandentalacademy.com
• By definition ultra sound has a
periodicity of greater than 20 kHz
• It is distinguished from other wave
forms simply ha...
How they work
• Scanners used for sonography
generate electrical impulses that are
converted to high frequency sound
waves...
www.indiandentalacademy.com
• Most commonly used piezoelectric
crystal is lead zirconate.
• The electrical impulse generated by
scanner causes dipoles...
• An ultra sound beam passes through or
interacts with the tissues of different acoustic
impedance,it is accentuated by a ...
www.indiandentalacademy.com
• Slice thickness of 0.5 mm or less.
• Real time imaging.
• Here image is produced by reflected
portion of the beam

www.i...
• The fraction of beam that is reflected
back depends on the acoustic
impedance of the tissue and is
characteristic for di...
Applications
• Imaging of the –
lymph nodes

www.indiandentalacademy.com
Applications
• Imaging of the –
thyroid gland

www.indiandentalacademy.com
Applications
• Imaging of the –
salivary glands

www.indiandentalacademy.com
Applications
Post surgical oedema and haematoma
Thickness of the masticatory mucosa
Displacement of soft tissue under forc...
Comparative data on facial
morphology and muscle thickness
using ultrasonography

• Fiikreet et al( EJO 2005)

www.indiand...
Xeroradiography

www.indiandentalacademy.com
• New method for recording images
without film.
• based on an electrostatic process
(similar to those used in paper copier...
Types of systems
• Medical 125 system (since 1970s)
• Dental 110 system (recently developed)

www.indiandentalacademy.com
How they work
• Image is recorded on a selenium
coated plate.
• Selenium plate given an electrostatic
charge in a conditio...
• The amount it discharges equals to the
amount of radiation striking the
receptor.
• The patter of electrical charge is
r...
Figure of process

www.indiandentalacademy.com
Development
• The plate is exposed to a cloud of
charged powder particles called as
toner.
• Individual toner particles ar...
www.indiandentalacademy.com
Dental 110 system
• Similar to the medical 125 system in
concept is physically different.
• The plates are of 1 and 2 size...
www.indiandentalacademy.com
www.indiandentalacademy.com
Advantages
• Edge enhancement (deposition of more toner
to the high charge side of the boundary and
less toner on the low ...
Applications
•
•
•
•

Mammography
Cephalometrty
Sialography
Detection of caries and alveolar bone
height ( progress of per...
TMJ tomography
• Bony margins are see in more detail
and sharply.
• Halender et al and Castrup and Shwatz
showed no signif...
www.indiandentalacademy.com
The role of xeroradiography in
cephalometry
• Davis et al (Journal dent 1977)

www.indiandentalacademy.com
Radiologic exposure conditions And
resultant skin doses in application of
xeroradiography to orthodontic
diagnosis

• Naka...
Conventional radiography vs.
xeroradiography
• Edge enhancement and wide latitude
• Greater ability to resolve structures
...
Laser holography

www.indiandentalacademy.com
Laser
• Light amplification by stimulated
emission of radiation.
• Coherence is the key property. (means
all the waves of ...
Holography
• Holos means whole
• Gramma means message
• An advanced form of photography,
allows an image to be recorded in...
History
• Denis Gabor – 1947 (Hungarian
physicist).
• Not until laser holography was so
popular. (conventional light sourc...
Lasers how they work
• Depends of certain characteristics of
certain atoms which have been raised
to an excited state,whic...
Two types of lasers
• Helium neon laser

www.indiandentalacademy.com
Two types of lasers
• Pulse ruby laser

www.indiandentalacademy.com
Holography basics
• Two step lens less imaging process
called as wavefront construction.
• An interference between the obj...
• The record known as hologram
captures the complete wave which can
be viewed at later date with appropriate
illumination....
• Because of need for interference
between the reference and object
beams, holograms typically need a
laser to produce the...
Types of holograms
• Reflection hologram
- most common type seen in
galleries
• Transmission hologram
- visa card

www.ind...
Holography in medicine

www.indiandentalacademy.com
X ray holography
• Imaging of internal body parts of the
body and living biological specimens
with very high resolution wi...
Multiplexed holography
• Complete display of 3d tomographic
medical data.
• Used in prostheses and craniofacial
surgery .
...
Endoscopic holography
• Potential for providing a powerful tool
for non contact high resolution 3d
imaging and non destruc...
Orthodontic applications
• Holographic study of variations in bone
deformations resulting from different
head gear forces ...
Holographic determination of the
centre of rotation produced by
orthodontic forces
• Burstone et al (AJO – DO 1980)

www.i...
Specialized radiographic techniques

Thank you
For more details please visit
www.indiandentalacademy.com

www.indiandental...
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Specialized radiographic techniques /certified fixed orthodontic courses by Indian dental academy

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The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and offering a wide range of dental certified courses in different formats.

Indian dental academy provides dental crown & Bridge,rotary endodontics,fixed orthodontics,
Dental implants courses.for details pls visit www.indiandentalacademy.com ,or call
0091-9248678078

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Specialized radiographic techniques /certified fixed orthodontic courses by Indian dental academy

  1. 1. RECENT ADVANCES IN DIAGNOSTIC AIDS INDIAN DENTAL ACADEMY Leader in continuing dental education www.indiandentalacademy.com www.indiandentalacademy.com
  2. 2. Specialized radiographic techniques www.indiandentalacademy.com
  3. 3. • • • • Digital subtraction radiography Xeroradiography Ultrasonography Laser holography www.indiandentalacademy.com
  4. 4. Digital subtraction radiography www.indiandentalacademy.com
  5. 5. • Requires two different images and the subtracted image is a composite of these two images representing their different densities www.indiandentalacademy.com
  6. 6. • Sensitive enough to detect a .12 mm change in the cortical bone. • The ability of this technique to detect minute changes is dependant on the degree of matching of the two images. www.indiandentalacademy.com
  7. 7. Technique • In DSR two standardized radiographs of anatomical region are made with identical exposure geometry at different time period. • The first radiograph is considered a reference image while the second radiograph taken at a later date is the image to be compared. www.indiandentalacademy.com
  8. 8. www.indiandentalacademy.com
  9. 9. • The first reference image is digitized and converted to a exact positive image by the computer and displayed on the TV screen as a positive image. • Then the second image is superimposed on the positive reference image www.indiandentalacademy.com
  10. 10. • Any differences between the two images will be shown on neutral gray background as brighter or darker areas depending on the nature of tissue changes. www.indiandentalacademy.com
  11. 11. • By this process a radiograph is converted to an array of points each of which has a specific optical density. • If each points of identical images is subtracted the result will be a neutral gray image. www.indiandentalacademy.com
  12. 12. • In clinical practice the two radiographs are taken one after he other ,after some time presuming some tissue changes have occurred • In DSR the changes otherwise not clinically visible are seen with subtle change in the densities of the two radiographs. www.indiandentalacademy.com
  13. 13. www.indiandentalacademy.com
  14. 14. Procedure • Digitization • To digitize a picture is taken using a video camera • Then computer digitizers place a grid over the radiograph and convert the continuous gray scale to different numbers between 0 –255 www.indiandentalacademy.com
  15. 15. Limitations • Diagnostic information can only be obtained when orientation of the x ray source,object and the image receptor is highly repeatable. • Subtracted image must be of the identical anatomical region. • Density and contrast of the original image should not effect that of the resulting image. www.indiandentalacademy.com
  16. 16. Overcoming the limitations • Computer algorithms have been developed for overcoming the variation in density and contrast. • The occlusal stants can be used to stabilize relationships between teeth film and x ray source. • Cephalostat can be used to stabilize x ray films and the teeth. www.indiandentalacademy.com
  17. 17. • Computer can be used to correct distortion caused by film placement • Reference points can be used to superimpose sequential radiographs. www.indiandentalacademy.com
  18. 18. Applications • Useful in diagnosis of periodontal and carious lesions. (both of which are characterized by insidious and slow rate of resorption). www.indiandentalacademy.com
  19. 19. Applications • Used for quantitative estimation of mass or volume of a lesion. measurement can be measured with the help of a wedge. www.indiandentalacademy.com
  20. 20. • Contrast enhancement with image in color can detect small change in bone. www.indiandentalacademy.com
  21. 21. • Useful in detection of small changes in mandibular condyle position and integrity of articular surfaces and or remodeling around granular hydroxyapatite implants. www.indiandentalacademy.com
  22. 22. • Assessment of failure of implant therapy and progress of periodontal therapy. www.indiandentalacademy.com
  23. 23. Image enhancement of mandibular condyle through digital subtraction • OOO 1987 ( south had et al ) www.indiandentalacademy.com
  24. 24. Radiographic evaluation of the effect of orthodontic retraction on the root of the maxillary canine • Perona and wenzel (dentomaxillofacial radiology 1996) www.indiandentalacademy.com
  25. 25. Digital subtraction radiography for assessing alveolar bone grafts:diagnostic accuracy and sensitivity • Maruko and Forbes ( 1993 ) www.indiandentalacademy.com
  26. 26. Ultrasonography www.indiandentalacademy.com
  27. 27. • By definition ultra sound has a periodicity of greater than 20 kHz • It is distinguished from other wave forms simply having a vibratory frequency greater than the audible range. • Diagnostic ultrasonography, the clinical application of ultrasound uses wave on the frequencies of 1 to 20 MHz www.indiandentalacademy.com
  28. 28. How they work • Scanners used for sonography generate electrical impulses that are converted to high frequency sound waves by a transducer. • The transducer consists of a thin piezo electric crystal or material made up of great number of dipoles arranged in a geometric pattern. www.indiandentalacademy.com
  29. 29. www.indiandentalacademy.com
  30. 30. • Most commonly used piezoelectric crystal is lead zirconate. • The electrical impulse generated by scanner causes dipoles within the crystal to realign themselves in the electric field . • This causes a change in the thickness which releases a series of vibrations that produces sound waves. www.indiandentalacademy.com
  31. 31. • An ultra sound beam passes through or interacts with the tissues of different acoustic impedance,it is accentuated by a combination of absorption, reflection, refraction and diffusion. • Sonic waves that are reflected back to the transducer cause a change in thickness of piezoelectric crystal, which in turn produces a signal which is processed and displayed on a monitor. www.indiandentalacademy.com
  32. 32. www.indiandentalacademy.com
  33. 33. • Slice thickness of 0.5 mm or less. • Real time imaging. • Here image is produced by reflected portion of the beam www.indiandentalacademy.com
  34. 34. • The fraction of beam that is reflected back depends on the acoustic impedance of the tissue and is characteristic for different tissues. (internal echo pattern). www.indiandentalacademy.com
  35. 35. Applications • Imaging of the – lymph nodes www.indiandentalacademy.com
  36. 36. Applications • Imaging of the – thyroid gland www.indiandentalacademy.com
  37. 37. Applications • Imaging of the – salivary glands www.indiandentalacademy.com
  38. 38. Applications Post surgical oedema and haematoma Thickness of the masticatory mucosa Displacement of soft tissue under forces of occlusion www.indiandentalacademy.com
  39. 39. Comparative data on facial morphology and muscle thickness using ultrasonography • Fiikreet et al( EJO 2005) www.indiandentalacademy.com
  40. 40. Xeroradiography www.indiandentalacademy.com
  41. 41. • New method for recording images without film. • based on an electrostatic process (similar to those used in paper copiers) www.indiandentalacademy.com
  42. 42. Types of systems • Medical 125 system (since 1970s) • Dental 110 system (recently developed) www.indiandentalacademy.com
  43. 43. How they work • Image is recorded on a selenium coated plate. • Selenium plate given an electrostatic charge in a conditioner. • Then the plate is exposed and the x-rays penetrate the body parts and strike the plate causing an electrical discharge. www.indiandentalacademy.com
  44. 44. • The amount it discharges equals to the amount of radiation striking the receptor. • The patter of electrical charge is referred to as a latent image. • This is converted to visible image by a process called development. www.indiandentalacademy.com
  45. 45. Figure of process www.indiandentalacademy.com
  46. 46. Development • The plate is exposed to a cloud of charged powder particles called as toner. • Individual toner particles are attracted to surface of the plate . • The association of the toner and plate is related to the distribution of the charge and is controlled by electric fields. www.indiandentalacademy.com
  47. 47. www.indiandentalacademy.com
  48. 48. Dental 110 system • Similar to the medical 125 system in concept is physically different. • The plates are of 1 and 2 size and fit conveniently into the oral cavity. • The plates are charge and developed in a single piece of equipment. www.indiandentalacademy.com
  49. 49. www.indiandentalacademy.com
  50. 50. www.indiandentalacademy.com
  51. 51. Advantages • Edge enhancement (deposition of more toner to the high charge side of the boundary and less toner on the low charge side ) • A choice of positive and negative displays • Good detail • Wide exposure of latitude. (imaging of objects of broad range of densities in a single exposure) www.indiandentalacademy.com
  52. 52. Applications • • • • Mammography Cephalometrty Sialography Detection of caries and alveolar bone height ( progress of periodontal diseases). • Detection of oral cancer • Imaging of bio materials. www.indiandentalacademy.com
  53. 53. TMJ tomography • Bony margins are see in more detail and sharply. • Halender et al and Castrup and Shwatz showed no significant difference between tomographic images and xeroradiographs. www.indiandentalacademy.com
  54. 54. www.indiandentalacademy.com
  55. 55. The role of xeroradiography in cephalometry • Davis et al (Journal dent 1977) www.indiandentalacademy.com
  56. 56. Radiologic exposure conditions And resultant skin doses in application of xeroradiography to orthodontic diagnosis • Nakasima et al (AJO DO 1980) www.indiandentalacademy.com
  57. 57. Conventional radiography vs. xeroradiography • Edge enhancement and wide latitude • Greater ability to resolve structures • Greater visualization of minute details of bone and teeth. • Require about one third exposure of conventional film. www.indiandentalacademy.com
  58. 58. Laser holography www.indiandentalacademy.com
  59. 59. Laser • Light amplification by stimulated emission of radiation. • Coherence is the key property. (means all the waves of light are going up and down together ) www.indiandentalacademy.com
  60. 60. Holography • Holos means whole • Gramma means message • An advanced form of photography, allows an image to be recorded in dimensions. www.indiandentalacademy.com 3
  61. 61. History • Denis Gabor – 1947 (Hungarian physicist). • Not until laser holography was so popular. (conventional light sources gave too little light or too much light). www.indiandentalacademy.com
  62. 62. Lasers how they work • Depends of certain characteristics of certain atoms which have been raised to an excited state,which when brought back to ground state release a package of electromagnetic radiation . www.indiandentalacademy.com
  63. 63. Two types of lasers • Helium neon laser www.indiandentalacademy.com
  64. 64. Two types of lasers • Pulse ruby laser www.indiandentalacademy.com
  65. 65. Holography basics • Two step lens less imaging process called as wavefront construction. • An interference between the object field and background wave (reference wave) is formed and recorded with photographic material. • The aim is to record both amplitude and phase. www.indiandentalacademy.com
  66. 66. • The record known as hologram captures the complete wave which can be viewed at later date with appropriate illumination. • The object can be considered to be made up of a number of point sources distributed in 3 dimensions. www.indiandentalacademy.com
  67. 67. • Because of need for interference between the reference and object beams, holograms typically need a laser to produce them • The light from laser produces two beams one is the reference beam and the other illuminating the object called as object beam www.indiandentalacademy.com
  68. 68. Types of holograms • Reflection hologram - most common type seen in galleries • Transmission hologram - visa card www.indiandentalacademy.com
  69. 69. Holography in medicine www.indiandentalacademy.com
  70. 70. X ray holography • Imaging of internal body parts of the body and living biological specimens with very high resolution without the need for sample preparation. www.indiandentalacademy.com
  71. 71. Multiplexed holography • Complete display of 3d tomographic medical data. • Used in prostheses and craniofacial surgery . • Volumetric multiplexed holograms. www.indiandentalacademy.com
  72. 72. Endoscopic holography • Potential for providing a powerful tool for non contact high resolution 3d imaging and non destructive measurements inside natural cavities of human body or in any difficult to access environment. www.indiandentalacademy.com
  73. 73. Orthodontic applications • Holographic study of variations in bone deformations resulting from different head gear forces in a macerated human skull (Andrej Zetner – AO 1995 ) www.indiandentalacademy.com
  74. 74. Holographic determination of the centre of rotation produced by orthodontic forces • Burstone et al (AJO – DO 1980) www.indiandentalacademy.com
  75. 75. Specialized radiographic techniques Thank you For more details please visit www.indiandentalacademy.com www.indiandentalacademy.com

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