1 dental radiology


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1 dental radiology

  1. 1. Warning This publication is provided solely for theimmediate study needs of students enrolled at theUniversity of Al-Azhar, Cairo, A.R.E. for thecourse directed by Dr. Ossama El-Shall.All rights reserved. No part of this publication maybe reproduced, stored in a retrieval system, ortransmitted, in any form or by any means,electronic, mechanical, printed, photocopying,recording or otherwise without the writtenpermission of the author. 01/25/13 00:59 Ossama El-Shall
  2. 2. Dental Radiology Dental Radiology Dr. Ossama EL-Shall Professor and Chairman of OralMedicine, Periodontology, Diagnosis and Radiology Department. Faculty of Dental Medicine for Girls Al-Azhar University , Cairo Egypt. 01/25/13 00:59 E-mail address: oelshall@hotmail.com Ossama El-Shall
  3. 3. Dental Radiology course for post graduate students. Physics of Ionizing Radiation. X-ray Machine. Biological effects of Radiation. Safety &Protection in dentistry. Dental X ray Film composition, (intra & extra-oral), Types & uses of intra-oral films. X-Ray film processing. Intra-oral radiographic techniques . Plain Extra-oral film projections . Panoramic Imaging. Faults affecting dental radiographs. Normal Anatomical Landmarks. Dental radiographic interpretation. Specialized techniques for imaging (Conventional tomography, CT, MRI, Nuclear medicine, Ultrasonography, Sialography) Cone-Beam Computed Tomography 01/25/13 00:59 Ossama El-Shall
  4. 4. Contents of part I1- Terminology.2- Radiation Physics.3- Properties of X-ray4- Dental X-ray apparatus.5- Production of X-rays.6- Types of radiation.7- Dental X-ray films, both intra-oral and extra-oral.8- X-ray film processing.9- Intra-oral radiographic techniques.01/25/13 00:59 Ossama El-Shall
  5. 5. Terminology1- Radiology2- Roentgenology3- Dental radiology4- Dental radiography5- Radiograph6- Radiation7- Radiolucent8- Radiopaque01/25/13 00:59 Ossama El-Shall
  6. 6. Radiology Science that deals with diagnosis, therapeutic and researches application of high- energy radiation.01/25/13 00:59 Ossama El-Shall
  7. 7. RoentgenologyScience that deals with application of X-ray on any field.01/25/13 00:59 Ossama El-Shall
  8. 8. Dental radiology It is the branch of science that deals with the use of radiation in diagnosis of dental diseases. 01/25/13 00:59 Ossama El-Shall
  9. 9. Dental radiography It is the art of producing an image or picture for intra- or extra-oral structures on a dental film using X-ray.01/25/13 00:59 Ossama El-Shall
  10. 10. Radiograph It is the shadow features (image) received on a radiation-sensitive film emulsion by exposure to ionizing radiation directed through an area or region or substance of interest, followed by chemical processing of the film. It is basically dependent on the differential absorption of radiation directed through heterogeneous media.  01/25/13 00:59 Ossama El-Shall
  11. 11. Radiation It is the process of emission, propagation and transmission of energy by atoms in the form of waves.01/25/13 00:59 Ossama El-Shall
  12. 12.   Radiolucent Objects that permitting the passage of radiant energy with relatively little attenuation by absorption and appear black on the film, such as silicate restoration, pulp tissues, gingiva, and carious lesion. Another definition; Objects partly or wholly penetrable by roentgen rays; the image of such a material on the film ranges from dark gray to black. RL RL 01/25/13 00:59 Ossama El-Shall
  13. 13.   Radiopaque Objects that absorb X-rays and appear white on radiograph, such as amalgam restoration, enamel, and bone. Another def.:Objects that not freely penetrable by radiation. OR Objects highly resistant to penetration by roentgen rays; the image of such a material appears on the film within range of gray to white. 01/25/13 00:59 Ossama El-Shall
  14. 14. Clinical Exam + Radiographs Diagnosis Treatment01/25/13 00:59 Ossama El-Shall
  15. 15. Radiation physics01/25/13 00:59 Ossama El-Shall
  16. 16. Radiation physics Atomic structure:1- Atom is the fundamental unit of any particular element, i.e. the basic unit of an element.2- It is composed of a central nucleus and outer orbits which spaced at a definite distance from the nucleus and are identified by letters, K, L, M, N, O, P, Q. 01/25/13 00:59 Ossama El-Shall
  17. 17. 3-Electrons are negatively charged particles that orbiting shells.4-The central nucleus is composed of two kinds of particles, proton, +ve charged and neutrons with no charge.5-Since neutrons have no charge; the magnitude of the charge of the nucleus will depend on the number of protons (Atomic number), which are equal to the number of electrons. 01/25/13 00:59 Ossama El-Shall
  18. 18. Atom statesGround state (stable): It is the normal or ground state of atom on which the atom is electrically neutral with equal numbers of protons and electrons.Excitation state: It occurs when sufficient energy applied to the atom, results in removing of electron from its normal shell to a higher energy shell.Ionization state: It is the process by which an atom loses its electrical neutrality and become ions by either addition or removing of electrons. If electron is added or removed from the atom, the atom will termed as ion. If the electron is removed, the atom becomes a +ve ion while the removed electron is called –ve ion. 01/25/13 00:59 Ossama El-Shall
  19. 19. Atom (electrically stable)K-shell protons L-shell neutrons M-shell electrons Atomic Number (Z) = # of protons 01/25/13 00:59 Ossama El-Shall
  20. 20. ELECTROSTATIC FORCE Attraction between protons and electrons01/25/13 00:59 Ossama El-Shall
  21. 21. CENTRIFUGAL FORCE Pulls electrons away from nucleus01/25/13 00:59 Ossama El-Shall
  22. 22. EF CF Balance between electrostatic force and centrifugal force keeps electrons in orbit around nucleus01/25/13 00:59 Ossama El-Shall
  23. 23. Nature of radiation Radiation may be either Corpuscular radiation Electromagnetic radiation01/25/13 00:59 Ossama El-Shall
  24. 24. A- Corpuscular or particulate radiation1- It is that type of radiation given off from radium, radioisotopes, and during splitting of the atom.2- It is composed of solid subatomic particles having mass and charge.3- It travels in straight lines and is not used in dental diagnostic filed but in therapeutic means.4- Examples for corpuscular radiation: Alpha (α) rays. Beta (β) rays.01/25/13 00:59 Ossama El-Shall
  25. 25. B- Electromagnetic radiation1-It is that type of radiation formed of units of pure energy, which are propagated in the form of waves as a combination of electric and magnetic fields.2-It is made of pure energy propagate in a form of waves with no mass or charge.3-It is generated when the velocity of an electrically charged particle is altered.01/25/13 00:59 Ossama El-Shall
  26. 26. 4-They travel in straight lines with the same speed of light (3x108 meter/sec.)5-As they propagate in a form of waves, they have a wavelength (λ) and frequency (ν(01/25/13 00:59 Ossama El-Shall
  27. 27. λ Wavelength (λ) is the distance between 2 crests or bottoms of 2 successive waves. Frequency (ν) is the number of cycles or waves emitted/sec.01/25/13 00:59 Ossama El-Shall
  28. 28. λ λ F Wavelength x Frequency = Speed of wave01/25/13 00:59 Ossama El-Shall
  29. 29. According to the wavelengths, radiations can differ in their properties.Radiation may be ofShort wavelength Or Long wave length01/25/13 00:59 Ossama El-Shall
  30. 30. The short wavelength increased frequency increase the energy accompanied with it increase the power of penetration the rays will termed Hard radiation which characterized with low power of absorption into matter and low ionization.01/25/13 00:59 Ossama El-Shall
  31. 31. The long wavelength decreases frequency decrease the energy accompanied with it decrease the power of penetration the rays are termed Soft radiation which characterized with high power of absorption into matter and high ionization effects.01/25/13 00:59 Ossama El-Shall
  32. 32. A Highest energyB Shortest wavelength Highest frequencyC Highest energy?01/25/13 00:59 Ossama El-Shall
  33. 33. Examples of electromagnetic radiationarranged in an ascending order according to their wavelength: 1-Cosmic rays. 2-Gamma Ray 3-X.Ray. wavelength = 0.1-1Ao, Ao = 10-10 m 4-Ultraviolet rays. 5-Visible light. 6-Infra-red. 7-Microwaves. 8-Radio, radar, T.V waves. 01/25/13 00:59 Ossama El-Shall
  34. 34. Electromagnetic Spectrum radio tv visible x-rays gamma cosmic light rays rays01/25/13 00:59 Ossama El-Shall
  35. 35. History History History X-ray X-rays were first discovered in 1895 by Wilhelm Conrad Roentgen, the professor of physics and director of the physics institute at the University of Wurzburg in Bavaria. Hence the term ROENTGEN RAYS, often applied to mechanically generated x-rays. He won a Noble prize for his discovery of X-ray. Roentgen called them X-rays after the mathematical symbol X for unknown. 01/25/13 00:59 Ossama El-Shall
  36. 36. History History History X-ray of Bertha Roentgens Hand Roentgen soon found that photographic plates were sensitive to the newly discovered rays. He convinced his wife to participate in an experiment. Roentgen placed her hand on a cassette loaded with a photographic plate. He then aimed the activated cathode ray tube at her hand for fifteen minutes. When the image was developed, the bones of her hand and the two rings she wore were clearly visible. 01/25/13 00:59 Ossama El-Shall
  37. 37. History History History Within 2 weeks after Roentgen was made his discovery public, the first dental radiograph was made by German dentist Otto Walkoff, who placed in his own mouth small glass photographic plates wrapped in rubber dam and exposed them for 25 minutes. 01/25/13 00:59 Ossama El-Shall
  38. 38. History History History Early x-ray machine. Arrow points to “live” electrical wire. 01/25/13 00:59 Ossama El-Shall
  39. 39. Definition of X-ray - It is a type of electromagnetic radiation characterized by wavelengths between approximately 1 A and 10-4 A. - They are invisible, penetrative especially at higher photon energies, and travel with the same speed as visible light. - They are usually produced by bombarding a target of high atomic number with fast electrons in a high vacuum01/25/13 00:59 Ossama El-Shall
  40. 40. In brief: X rays are a form of pure energy units belonging to electromagnetic spectrum characterized by having a very short wave length and have the ability of producing shadiness’ or images of the body tissues.01/25/13 00:59 Ossama El-Shall
  41. 41. Properties of X-ray01/25/13 00:59 Ossama El-Shall
  42. 42. Properties of X-ray 1- They have a very short wave length: As the wavelength decrease, the power of penetration of the x-ray increased. The power of penetration depends on several factors in addition to the wavelength such as: Atomic number of the object, thickness of the object, and the density of the object.01/25/13 00:59 Ossama El-Shall
  43. 43. 2- They have a selective penetration, absorption power: When the x-ray hit an object, certain interactions occur, these interactions may occur in either of 3 forms or possibilities: a) Penetrate the object, b) Absorbed by the object, c) Deflected from certain objects e.g. heavy metals01/25/13 00:59 Ossama El-Shall
  44. 44. 3- It affects photographic film’s emulsion: X-rays upon falling on the emulsion of a photographic film they cause physical changes producing what is termed Latent Image formation, which cannot be seen except after chemical application.01/25/13 00:59 Ossama El-Shall
  45. 45. 4- It causes certain substances to fluoresce: X-ray can cause certain fluorescing substances to fluoresce or emit “violet blue visible light” which is of a longer wave length than the x- rays so this was used in dentistry in the formation of intensifying screen.01/25/13 00:59 Ossama El-Shall
  46. 46. 5- They cause ionization of atoms: X- rays have the power of converting atoms into ions with the formation of ion pairs which are electrically charged, unbalanced, non-functioning cells thus will have a harmful effect later on the body cells and fluids.01/25/13 00:59 Ossama El-Shall
  47. 47. 6-They have biological damaging effects: May be of somatic effects such as skin burns, erythema or cancer or genetic effects01/25/13 00:59 Ossama El-Shall
  48. 48. 7. Travel in straight lines in wave motion with the same speed of light.3x108 meter/sec.8. Short waves about 1/10000 of that of light. (0.1-0.001nm)9. Invisible, can’t be felt, smelled or heard.10. Weightless, mass less, and changeless. 01/25/13 00:59 Ossama El-Shall
  49. 49. 11. They cannot be focused or collected by a lens.12. They cannot be reflected by a mirror or by fluids.13. They cannot be deviated by a magnet.14. They can deflect on heavy metals by deviated into a new linear trajectory.01/25/13 00:59 Ossama El-Shall
  50. 50. X-Ray Machine01/25/13 00:59 Ossama El-Shall
  51. 51. Dental X-ray apparatusHow are X-rays created? When fast-moving electrons (minute particles each consisting of a negative electrical charge) collide with matter, X-radiation is produced. The most efficient means of generating X-rays is an X-ray tube. In it, X-rays are produced by directing a high- speed stream of electrons against a metal target. As they strike the atoms of the target, the electrons are stopped. Most of their energy is transformed into heat, but a small proportion is transformed into X-rays.01/25/13 00:59 Ossama El-Shall
  52. 52. X-ray machine consists of Tube: Cathode + AnodeHead Accessories: Filters + collimators + cones Automatic Timer Manual01/25/13 00:59 Ossama El-Shall
  53. 53. X-ray Tubehead01/25/13 00:59 Ossama El-Shall
  54. 54. support arms Tubehead Timer01/25/13 00:59 Ossama El-Shall
  55. 55. Automatic timers 1- Direct or immediate timers: It attached to a long cord to enable the operator to go away from the field of radiation. Operator press on a button just to activate the exposure while the time is pre adjusted and the exposure will stop automatically even if the operator continuous to press the button.2- Delayed timers: This type provide about 9 second before the start of exposure, so it provides the operator a period to get away from the field of radiation.01/25/13 00:59 Ossama El-Shall
  56. 56. Timer exposure time adjustment01/25/13 00:59 Ossama El-Shall
  57. 57. 01/25/13 00:59 Ossama El-Shall
  58. 58. Manual timers - Direct type in old x-ray machines -The exposure is controlled manually (like the clock alarm) and exposure will stop only if the operator stop pressing on the button. - The main disadvantage of this type that it adjusted only for 1 second not in fraction of seconds.01/25/13 00:59 Ossama El-Shall
  59. 59. Manual Timer01/25/13 00:59 Ossama El-Shall
  60. 60. Head of X-ray machine. It consists of two main parts Tube Accessories.01/25/13 00:59 Ossama El-Shall
  61. 61. The Tube The Tube is an Evacuated glass tube with two arms or electrodes extending in two opposite directions, which are the cathode and anode.The tube is evacuated for two reasons1) This will prevent collision of the moving electrons with the molecules of the air. 2) This evacuation will prevent oxidation and burn out of the filaments.01/25/13 00:59 Ossama El-Shall
  62. 62. Tube head of X-ray machine01/25/13 00:59 Ossama El-Shall
  63. 63. CathodeIt is the negative electrode of the tube, which serves as the source of electrons. It consists of two parts a) Filament. b) Focusing cup.01/25/13 00:59 Ossama El-Shall
  64. 64. Cathode Filament (tungsten)Focusing cup(molybdenum) 01/25/13 00:59 Ossama El-Shall
  65. 65. Filament It made of tungsten coil, which is 0.2cm indiameter and 1 cm or less in length.Tungsten is used because;1) It has a very high melting point so it canwithstand the high temperature accompaniedwith the process of X-ray production. 2) It has a high atomic number, whichdenoting a high number of protons resulting inhigh number of electrons.01/25/13 00:59 Ossama El-Shall
  66. 66. Focusing cup It is a negatively charged concave reflector cup made of molybdenum, act as focusing to the electrons to a narrow beam to fall on the target. The high negative charge of the cathode repels the negatively charged electrons, thus this cup collects the electrons and repels them till the anode attracts them.01/25/13 00:59 Ossama El-Shall
  67. 67. Electrons EmissionRelease of electrons from hot filament whencurrent flows after depressing exposure switch hot filament filament electrons The hotter the filament gets, the greater the number of electrons that are released.01/25/13 00:59 Ossama El-Shall
  68. 68. AnodeIt consisting of two main parts a) Target. b) Copper head.01/25/13 00:59 Ossama El-Shall
  69. 69. Anode side view front view Target Copper head Target01/25/13 00:59 Ossama El-Shall
  70. 70. Target It made up of tungsten due to 1) It has a very high atomic number (i.e. large number of protons and electrons). 2) It has a high melting point. 3) It has a very poor thermal conductivity.01/25/13 00:59 Ossama El-Shall
  71. 71. Copper head Due to the poor thermal conductivity of the tungsten target, it is embedded in a large block of copper, which is a good thermal conductor so it allows proper dissipation of heat which accompanies the process of X-ray production.01/25/13 00:59 Ossama El-Shall
  72. 72. X-ray Production01/25/13 00:59 Ossama El-Shall
  73. 73. A simplified diagram of x-ray tube 220 v Cathode Anode Step-down Step-uptransformer transformer Filament 60-90 kvp E Target 8-12 v Copper head Focusing cup 1ry RayInsulating oilMetal housingEvacuated Glass tube Useful beam 01/25/13 00:59 Ossama El-Shall
  74. 74. Production of X-raysTerminology:Volt Voltage Ampere Transformer01/25/13 00:59 Ossama El-Shall
  75. 75. Volt: It is the unit of electrical pressure or electromotive force necessary to produce a current of 1 ampere through a resistance of 1 ohm. OR It is the unit of measuring the potential difference of a charge to move from one electrode to the other01/25/13 00:59 Ossama El-Shall
  76. 76. Voltage: It is the potential or electromotive force of an electric charge, expressed in volts. OR The potential difference between 2 electrical charges, e.g. between cathode and anode.01/25/13 00:59 Ossama El-Shall
  77. 77. Ampere: It is the practical unit of quantity of electronic current, equal to a flow of 1 coulomb per second or the flow of 6.25 x 1018 electrons per second.01/25/13 00:59 Ossama El-Shall
  78. 78. Transformer: It is an electrical device, which increases or reduces the voltage of an alternating current by mutual induction between primary and secondary coils.  Step-down transformer: A transformer in which the secondary voltage is less than primary voltage.  Step-up transformer: A transformer in which the secondary voltage is greater than the primary voltage.01/25/13 00:59 Ossama El-Shall
  79. 79. The principles of X-ray production When an electric current, -which composed ofa steam of negatively charged electrons havingkinetic energy- passes through a filament orwire, it will be heated so the orbiting electronswithin its atoms will acquire sufficient energy toescape from their shells. Finally this electroncloud will be given from the heated wire offilament. If these electrons sudden stopped, they willloose the accompanying kinetic energy andconverted into heat and X radiation. 01/25/13 00:59 Ossama El-Shall
  80. 80. Application of this principle on dental X-ray machineThe step-down transformer will decrease theelectric current into 8-12 volts.This current is sufficient enough to heat thetungsten filament of the cathode and produceelectrons according to the degree of heatingby thermo ionic emission. These electrons will form a cloud around thecathode, which will be collected by the concavefocusing cup but they have no velocity to move.01/25/13 00:59 Ossama El-Shall
  81. 81. The step-up transformer will raise the potentialdifference between the cathode and the anodeby raising the voltage into 60-70 KV. This increase in potential difference willaccelerate the electron cloud to move towardsthe anode, as there is a force of attractionbetween the positive anode and the negativecathode.By the action of the focusing cup, the electronswill hit only the tungsten target of the anode,loosing their kinetic energy in a form of 99.8%heat and only 0.2% X-rays. The produced X-rays (primary beam) areconducted to get out from the tube housingthrough the filters and collimators to be used asa useful beam. 01/25/13 00:59 Ossama El-Shall
  82. 82. Tube of x-ray machine01/25/13 00:59 Ossama El-Shall
  83. 83. X-ray Machine Components oil filament filter exposure button01/25/13 00:59 Ossama El-Shall
  84. 84. Accessories Filters Collimators Cones01/25/13 00:59 Ossama El-Shall
  85. 85. Filters A thin sheet of pure aluminum placed in the way of the X-ray beam at the end of the X-ray tube in order to improve the quality of the beam. The X-ray beam is heterogeneous in characteristics i.e. containing a ray of different energies and wavelength. Because of this, the filter is used in order to absorb unnecessary x-rays of the longer wavelengths being both useless in radiography and dangerous to the patient and the dentist. The thickness of the filters varies according to the Kvp of the machine being used, 2mm.Al thickness with up to 70Kvp and 2.5mm over 70Kvp.01/25/13 00:59 Ossama El-Shall
  86. 86. PIDThe filter is usuallylocated in the end ofthe PID whichattaches to thetubehead. filter01/25/13 00:59 Ossama El-Shall
  87. 87. Types of filtersAdded filters: They are external filters that can be removed or added by the clinician.Inherent filters: These include the glass wall of the X-ray tube, The insulating oil, and the metal housing Total filters = Inherent filters + added filters.01/25/13 00:59 Ossama El-Shall
  88. 88. Total Filtration Aluminum filter (s) Added 2.5 mmGlass window Total 70 kVp Oil/Metal barrier 1.5 mmof x-ray tube Inherent 01/25/13 00:59
  89. 89. Collimator It is a device used to limit or restrict the size of an X-ray beam just to cover the film to produce the desire image.01/25/13 00:59 Ossama El-Shall
  90. 90. Types of collimatorsDiaphragm collimator: A thin sheet of lead with an opening in the center.Tubular collimator: A tube of lead with one of its ends connected or in conjunction to the diaphragm collimator. This tube will help in decrease diverging rays and almost increase more parallel rays, which in turn helps in increase quality of image and more safe to the patient.Rectangular collimators: It provides a beam of a rectangular shape that larger than the size of Periapical films.01/25/13 00:59 Ossama El-Shall
  91. 91. Collimation front views side view collimated collimator beam target (x-ray source) 2.75 inches (7 cm) = maximum diameter of circular beam or maximum length of long side of rectangular beam at end of PID.01/25/13 00:59 Ossama El-Shall
  92. 92. Collimator You are looking up through the PID at the collimator, which is a circular lead washer with a circular cutout in the middle. This will produce a round x-ray beam. The light gray area in the center is an aluminum filter, which is placed on the tubehead side of the PID.01/25/13 00:59 Ossama El-Shall
  93. 93. 7 cm If you switch from a 6 cm 7 cm round PID to a 6 cm round PID, the 6 cm round patient receives 25% less radiation. film (4.5 cm long) Rectangular collimation results in 55 % less entrance radiation when compared to 7 cm round PID. entrance exit exit01/25/13 00:59 Ossama El-Shall
  94. 94. Cones, Position indicating device (PID) It is a device used to1-Fix the target film distance2-Indicate the point of the entry3-Determine the direction and distribution of the X-ray tube.01/25/13 00:59 Ossama El-Shall
  95. 95. It may make of plastic, glass or metal. The majority of cones are made of plastic because it is light. In case of metal one (lead) it may act as collimator and cone in the same time, but it is not practical as it very heavy on the tube itself and will cause decrease beam intensity as some of it will be absorbed by the lead. It may be of opened end or pointed end shape. The pointed end shape has harmful effects that it acts as a source of scattered radiation as the rays will hit its walls.It may be short one 8” or long one 16”.01/25/13 00:59 Ossama El-Shall
  96. 96. 16” FFD image Target 16” from film Target 8” from film 8” FFD image FilmIncreasing the distance from the target of the x-ray tube(focal spot, focus) to the object (teeth/film) (FFD = focus-filmdistance) will result in an increase in sharpness and a decrease inmagnification. This results when a longer PID (cone) is used.Moving the film closer to the teeth will also increase sharpnessand decrease magnification. 01/25/13 00:59 Ossama El-Shall
  97. 97. Types of X-ray01/25/13 00:59 Ossama El-Shall
  98. 98. Types of X-Radiation1- Primary radiation.2- Useful beam3- Central ray4- Secondary radiation5- Scattered radiation6- Stray radiation7- Remnant radiation8- Leakage radiation9- Soft radiation10-Hard radiation01/25/13 00:59 Ossama El-Shall
  99. 99. Primary radiation: It is the radiation coming directly out of the target, most of it is absorbed by the tube housing except for the useful beam.Useful beam: It is that part of the primary radiation, which is not absorbed by the housing but passes through the apparatus and affects the film.Central ray: It is that part occupying the central portion of the useful beam on which the rays are relatively parallel to each other.01/25/13 00:59 Ossama El-Shall
  100. 100. Secondary radiation: It is that radiation generated from the patient’s surrounding objects due to passage, interaction of the primary beam with these objects. They are of a long wavelength and so increased absorption and are more dangerous to the patient.Scattered radiation: It is a form of secondary radiation which has been deviated in direction during passage of the X- rays through objects.01/25/13 00:59 Ossama El-Shall
  101. 101. Stray radiation: This radiation occurs when the primary beam hits a metal heavier than AL, e.g. metallic eyeglasses.Remnant radiation: It is that portion of radiation remaining or emerging from the object after the passage of the primary beam through it, to expose the film and produce the image.Leakage radiation: The radiation that escapes through the protective housing of the X- ray tube.01/25/13 00:59 Ossama El-Shall
  102. 102. Soft radiation: Radiation produced by decreased kilo-voltage, are of longer wavelength, decreased penetration, increased absorption so have a more damaging effect.Hard radiation: Radiation produced by increased kilo-voltage, are of shorter wavelength, increased energy, increased penetration, decreased absorption and are the ones used to produce the image, i.e. of diagnostic value.01/25/13 00:59 Ossama El-Shall
  103. 103. Factors affecting the quality of an image Terminology Image Contrast Density Exposure Roentgen Rad Rem01/25/13 00:59 Ossama El-Shall
  104. 104. Image: The representation or semblance of a structure or structures produced by passage of X-radiation, visible only when transmitted onto a fluorescent screen or an x-ray film (in the latter case, visible only after processing the film).01/25/13 00:59 Ossama El-Shall
  105. 105. Contrast: It is the difference in density appearing on a radiograph. OR Is the differentiation between black, white and gray shades on the radiograph.01/25/13 00:59 Ossama El-Shall
  106. 106. Density: It is the degree of darkening of exposed and processed photographic or x-ray film, expressed as the logarithm of the opacity of a given area of the film. 01/25/13 00:59 Ossama El-Shall
  107. 107. Exposure: A measure of the x radiation to which a person or object, or a part of either, is exposed at a certain place, this measure being based on its ability to produce ionization.01/25/13 00:59 Ossama El-Shall
  108. 108. Roentgen; R: X-radiation has a property of causing ionization of the matter that passes through it.So, the unit of x-rays is Roentgen, which is the measurement of ionization. It is defined as the amount of radiation that passes in one c.c. air producing two billion ion pairs (–ve and +ve) under standard conditions of temperature and atmospheric pressure01/25/13 00:59 Ossama El-Shall
  109. 109. Rad: It is unit of absorbed dose; it is amount ofionizing Radiation absorbed dose by one gramof the tissues.Rem:It is the unit of biological damaging effect ofradiation (B.D.E),it is the amount of ionizing radiation producesbiologic damage effects (B.D.E) in one gramof tissue. It is Roentgen equivalent mass, i.e.measurement unit denoting amount of aradiation dose that produced biologicaldamaging effects equal that in a person withone Roentgen of X-ray.01/25/13 00:59 Ossama El-Shall
  110. 110. The factors affecting the quality of an image1- Kilo-voltage2- Milliamp rage3- Collimation4- Filtration5- Distance6- Atomic number and thickness (density) of the object 01/25/13 00:59 Ossama El-Shall
  111. 111. Kilo-voltage Kilo voltage power of conventional dental X-ray machine ranges from 65-90 kvp.X-ray penetration power is controlled with kvp,i.e. the higher the kvp is, the shorterwavelength x-ray with high penetration power. So kvp is the factors, which determine thequality of the x-ray beam, and when thethickness of the structure increased we need ahigher kvp.01/25/13 00:59 Ossama El-Shall
  112. 112. Kilo-voltage If the kvp is increased above the normalrange it will affect the contrast of the image. In this case of very high kvp, the penetrationpower of the x-ray will increase resulting innearly complete penetration of the objects andfinally blacking the film and the areas whichshould have been white (as metal) will appeargray. The end result of such image will be imagewith black and gray shades with low contrastimage (long gray scale).01/25/13 00:59 Ossama El-Shall
  113. 113. Kilo-voltageIf the kvp will decrease than the normal, thepenetration power of the beam will decreasedresulting in image with white colorrepresenting hard objects and few blacking orgray represent soft tissue objects, which iscalled high contrast image or (low gray scale).Thus an optimum contrast is required which isachieved by range of kvp between 65-90, anyalterations in this range either increase ordecrease will affect the quality of the imagecontrast.01/25/13 00:59 Ossama El-Shall
  114. 114. Milliamp rageThe normal range of mA is about 5-15, it is affecting the quantity of the x-ray. By controlling mA and time we cancontrol the quantity of the beam, andthus control the density of the image. 01/25/13 00:59 Ossama El-Shall
  115. 115. Milliamp rage The higher mA (within normal range) willresult in increase the quantity of the current,increase heating of the coil, increase theamount of electrons emitted, increase thenumber of x-ray photons, increase the amountof x-ray reaching the film, with final resultantof increasing the amount of blacking of theimage resulting in an image with good density. 01/25/13 00:59 Ossama El-Shall
  116. 116. While if the mA is increased above the normal range this will result in increasing the darkness of the image (high density), which may controlled or avoided by decreasing the time of exposure.01/25/13 00:59 Ossama El-Shall
  117. 117. If the mA is low than the normal range it will result in a very light image with low density, which is may control by increasing the exposure time.01/25/13 00:59 Ossama El-Shall
  118. 118. Collimation Collimators exerts three main functions, the first increase the safety to the patient,the second, increase the quality of the imagethe third is increase the sharpness of theimage. It helps on reduction the amount of x-rayreached to the patient and in the same timeincrease the image quality by decreasing theamount of scattered radiation. The imagesharpness will also increased by reduction ofthe beam size, leads to reduction the morediverging rays and increase the more parallelrays.01/25/13 00:59 Ossama El-Shall
  119. 119. Filtration Proper filtration will provide x-rays withshort wavelength, results in a goodquality image.Over-filtration will result in decrease theamount of x- ray photons and indecreased density image, while under-filtration will give a long wavelength x-rays with low penetration power and lowcontrast image..01/25/13 00:59 Ossama El-Shall
  120. 120. Distance The distance between the source and the objectmay affect the image quality as follow; if the distance is increased, the intensity of thebeam will decreased leading to decrease of thequality of the rays and affection to the density,but in the same time if the distance is increasedit help on production of less diverging raysleading to increase the quality of the beam andincrease the sharpness. If the distance is decrease, this will help onincrease the intensity of the beam and increasethe density; while in the same time will increasethe divergent rays leading to decrease thesharpness.01/25/13 00:59 Ossama El-Shall
  121. 121. Atomic number and thickness (density) of the object As the atomic number, density and thickness of the object increase, the need for more powerful x-radiation will increase to produce a good image. So the kvp should increased but within limits in order not to alter the contrast. So this may compensate with increase the exposure time, but also within limits in order not to affect the density.01/25/13 00:59 Ossama El-Shall
  122. 122. 01/25/13 00:59 Ossama El-Shall
  123. 123. Dental X-ray film01/25/13 00:59 Ossama El-Shall
  124. 124. Dental X-ray film It is a thin, transparent sheet of plastic material coated on both sides with an emulsion sensitive to radiation and light. Radiographic films closely resemble the films used by photographers to produce black and white negatives. There are differences in that photographic films only carry an emulsion on one side of the film base, whereas both sides of radiographic films are coated, to double the response to an X-ray exposure.01/25/13 00:59 Ossama El-Shall
  125. 125. The X-ray film basically consists of four components: Film base Adhesive layer Film emulsion Protective layer01/25/13 00:59 Ossama El-Shall
  126. 126. Film base Is a flexible piece of plastic, about 0.008inches thick to provide the desired degree ofstiffness and flatness for handling. It is transparent and has a slight blue tintto make it easier to visualize the image. Film base serve as a stable support for theemulsion.01/25/13 00:59 Ossama El-Shall
  127. 127. Adhesive layer It is a thin layer of adhesive material to act as attachment between the base and emulsion from both sides.01/25/13 00:59 Ossama El-Shall
  128. 128. Film emulsion1. This is the most important constituent of the film.2. It is a homogeneous mixture of gelatin and silver halide crystals coated on both sides of the film base to provide maximum speed to the film (sensitivity).3. Gelatin is used to suspend and evenly disperse the silver halide crystals. 01/25/13 00:59 Ossama El-Shall
  129. 129. 4. Halide crystal is a chemical compound that is sensitive to radiation or light.5. The halides used in a dental X-ray film are silver bromide and to a lesser extent silver iodide.6. On exposure to the X-ray this silver bromide absorb the rays and physical changes take place in the emulsion. This change called the latent image. 01/25/13 00:59 Ossama El-Shall
  130. 130. Protective layer It is a thin, transparent, clear layer of gelatin covers the emulsion to protect it from mechanical damage.01/25/13 00:59 Ossama El-Shall
  131. 131. What is the latent image and how it formed? Silver bromide crystals absorb X-radiation, andstore the energy of the radiation as a certainpattern to an extent depending on the density ofobjects. This pattern of energy on the exposed film cannotbe seen and is referred to as latent image. The latent image remains invisible within theemulsion until the film undergoes chemical processing,then it become visible.01/25/13 00:59 Ossama El-Shall
  132. 132. When the X-ray hit the surface of emulsion, the silver bromide crystals that exposed to the rays ionized and separated to silver and bromide atoms. However, when the exposed film is treated with a solution called a developer, a chemical reaction takes place, and the exposed grains of silver compound are transformed to tiny masses of black metallic silver. The unexposed grains are essentially unaffected. It is this silver suspended in the gelatin that constitutes the visible image on the radiograph.01/25/13 00:59 Ossama El-Shall
  133. 133. Latent ImageAir/soft tissue Bone Amalgam/MetalMany x-rays Fewer x-rays Few, if any, x-rayspenetrate and ionize penetrate and not as penetrate; silvermany silver halide many silver halide halide crystals notcrystals crystals are exposed exposed01/25/13 00:59 Ossama El-Shall
  134. 134. Types of Dental X-ray films Intra-oral films Extra-oral films01/25/13 00:59 Ossama El-Shall
  135. 135. Films used in dental radiography come in a variety of sizes and packaging. Those of the smaller sizes suitable for Intra-oral use, ranging from 22 to 31 mm across and from 35 to 54 mm in length, come individually enclosed in light-tight envelopes of thin plastic or paper. Other films of large size are used for extra-oral exposure in dental radiography. They positioned outside the oral cavity in a special light protected holder (cassette) that is loaded within the selected film inside the dark room.01/25/13 00:59 Ossama El-Shall
  136. 136. I- Intra-oral filmsIntra-oral films usually supplied inside special film packets. The film packet consists of:1-Outer packet wrapping or envelope2-Black paper film wrapping3-The film4-Lead foil sheet01/25/13 00:59 Ossama El-Shall
  137. 137. black paper surrounds film; protects emulsion filmsingle or double;raised dot in one corner lead foilprotects film from backscatter; reduces patientexposure; strengthens packet; pattern identifies whenfilm is placed backwards (reversed) 01/25/13 00:59 Ossama El-Shall
  138. 138. Outer packet wrapping or envelope: It is a soft plastic wrapper to protect the film completely from the light and saliva. It has two sides; white smooth side (tube side), which has a raised bump on one corner, corresponds to the identification dot on the film. The other side (the label side) has a flap used to open the film packet during processing. It contains data about the number of films per packet, and the film speed. It also contains a circle of concave dot that represent the identification dot of the film.01/25/13 00:59 Ossama El-Shall
  139. 139. Outer film coverKeeps out light and moisture; protects emulsion plastic dot paper # of films in packet #2 Tab #2 #1 01/25/13 00:59 Ossama El-Shall
  140. 140. Black paper film wrapping: Are two black papers enclose the film between them and further protect it from light.01/25/13 00:59 Ossama El-Shall
  141. 141. The film: It is a double emulsion film; the packet may contain one or two films. At one of the film corners there is a small raised dot (identification dot). It used after film processing to distinguish between the left and right side of the patient mouth during reading of radiograph (interpretation).01/25/13 00:59 Ossama El-Shall
  142. 142. This identification dot or bump has aconvex and concave surfaces the convexsurface should face the rays while theconcave side being back to the film duringexposure. Also it should be always away from anyanatomical landmarks to avoid misdiagnosedas any pathologic lesion, so it should beocclusally or incisally during exposure.01/25/13 00:59 Ossama El-Shall
  143. 143. Lead foil sheet: Placed back to the film away from the smooth side of the film packet (back side). Its function is to absorb the back scattered radiation and thus protects the film from fogging.01/25/13 00:59 Ossama El-Shall
  144. 144. It also adds to the rigidity of the film packets. It has a special pattern (herring bone) stamped on the exposed finished radiograph if the film is exposed from the wrong side.(back side film)01/25/13 00:59 Ossama El-Shall
  145. 145. black paper surrounds film; protects emulsion filmsingle or double;raised dot in one corner lead foilprotects film from backscatter; reduces patientexposure; strengthens packet; pattern identifies whenfilm is placed backwards (reversed) 01/25/13 00:59 Ossama El-Shall
  146. 146. Backscatter (scattered x-rays that go “back” toward the film) Primary x-rays01/25/13 00:59 Ossama El-Shall Scatter (secondary) x-rays
  147. 147. Reversed Films (back side film)01/25/13 00:59 Ossama El-Shall
  148. 148. Types of intra-oral films01/25/13 00:59 Ossama El-Shall
  149. 149. Intra-oral films Intra-oral films can be classified mainly according to their usage into Periapical films Bite-wing films Occlusal films.01/25/13 00:59 Ossama El-Shall
  150. 150. Also intra-oral films can classified according their * Speed * Size * Number of films per packet * Whether the film packet is lead backed or not.01/25/13 00:59 Ossama El-Shall
  151. 151. Classification of intra-oral films according to use Periapical films Occlusal films Bite wing films01/25/13 00:59 Ossama El-Shall
  152. 152. Periapical Film Periapical pathologyApical pathologyPeriodontal evaluation internal resorptionCaries detectionEndodontic treatment caries01/25/13 00:59 Ossama El-Shall
  153. 153. Periapical films It is the most frequently used intra-oral view, which shows the entire tooth and surrounding structure on the film. There are three basic sizes for Periapical films, No. 0 or child film 22x35mm. No. 1 or narrow adult 27x54mm. No. 2, or standard adult film 31x41mm. Periapical films used to exam the following:01/25/13 00:59 Ossama El-Shall
  154. 154. I-Enamel:1-Normally appears as a Radiopaque structure.2-Caries of the enamel: which appears as a radiolucent area.3-Enamel hypoplasia: appears as a radiolucent area surrounded with radio- opaque margin.4-Amilogenesis imperfecta: all the enamel appears as radiolucent area.5-Congenital syphilis: Hutchinson’s incisors; appears as v-shaped radiolucent area surrounded by radio-opacity. 01/25/13 00:59 Ossama El-Shall
  155. 155. II-Dentin:1-Normally appears as a Radiopaque structure-2Caries of the dentin; appears as a v- shaped radiolucent area.3-Dentinogenesis imperfecta: dentin appears as a radiolucent area surrounded by faint radio-opaque margin4-Dense in dente: appears as a radio-opaque structure within the tooth surrounded by radiolucent margin.5- Internal resorption: radiolucent lines on the apex or lateral side of the root dentin. 01/25/13 00:59 Ossama El-Shall
  156. 156. III-Pulp:1-Normally appears as a radiolucent area within the tooth.2-Calcification of the pulp: appears as a localized area of radiopacity = pulp stone. If it generalized it appears as a generalized radioopacity of the pulp chamber.3-Shell tooth : appears as a wide pulp chamber.01/25/13 00:59 Ossama El-Shall
  157. 157. IV-Cementum:1-Normally it cannot be differentiated from the dentin.2-Hypercementosis: appears as Radiopaque areas cover the cementum line.3-Cementoma: appears at the apex of the tooth as a radiolucent area in its early stages and converted into a Radiopaque area at its terminal stages.01/25/13 00:59 Ossama El-Shall
  158. 158. V-Periodontal ligament space:1-Normally appears as a radiolucent line surround the root surface2-Narrowing of it as a result of an oeteoblastic process e.g. scleroderma3-Widening of the space as results of osteolytic process e.g. osteolytic osteoma, .01/25/13 00:59 Ossama El-Shall
  159. 159. VI-Lamina dura:-Appears as Radiopaque clear continues band covers the alveolar bone ie. lining the socket and cover the crest of the crest of alveolar bone (crestal lamina dura).-Discontinuities of lamina dura indicate pathological changes.01/25/13 00:59 Ossama El-Shall
  160. 160. VII-Alveolar bone:Bone resorption either horizontal or vertical.01/25/13 00:59 Ossama El-Shall
  161. 161. Bite wing filmsThese films often have a paper tab projecting from the middle of the film, on which the patient bites to support the film. This tab is not visualized and does not interfere with the diagnostic quality of the image.It used to record the coronal portions of maxillary and mandibular teeth in one image. The apices of the teeth are not shown.It used for the following: 01/25/13 00:59 Ossama El-Shall
  162. 162. Bitewing Film Interproximal Caries Alveolar Bone Involvement01/25/13 00:59 Ossama El-Shall
  163. 163. 01/25/13 00:59 Ossama El-Shall
  164. 164. Overhanging amalgam filling01/25/13 00:59 Ossama El-Shall
  165. 165. 1. Detection of initial proximal caries.2. Detection proximal overhanging margins of fillings and crowns.3. Approximate estimation of the size of the pulp chamber and pulp horns.4. Detection of initial interproximal crestal alveolar bone resorption indicating periodontal disease.5. Determination of the position of permanent forming teeth in relation to deciduous ones.6. Determination of any proximal calculus formation. 01/25/13 00:59 Ossama El-Shall
  166. 166. Detection of proximal caries by bite wing radiographs compare to Periapical radiograph01/25/13 00:59 Ossama El-Shall
  167. 167. Occlusal filmsOcclusal films are use to radiographically clarify the anatomical structures and the pathological conditions of the maxilla or mandible in the bucco-lingual dimension.Occlusal films may use for the following purposes:01/25/13 00:59 Ossama El-Shall
  168. 168. Occlusal FilmIdentify large lesionsLocate bucco-linguallyDeveloping anterior teethImaging trismus patients 01/25/13 00:59 Ossama El-Shall
  169. 169. 1. Obtaining gross views for the jaws in the bucco-lingual dimension.2. Detection location and extent of fractures.3. Detection of the bucco-lingual direction of impactions and supernumerary teeth.4. Detection of bucco-lingual direction of displaced fracture.5. Detection of salivary gland or duct stone especially in the mandible.6. Localization of foreign bodies such as broken needle.7. Determination of the shape of dental arches.01/25/13 00:59 Ossama El-Shall
  170. 170. 01/25/13 00:59 Ossama El-Shall
  171. 171. 01/25/13 00:59 Ossama El-Shall
  172. 172. Classification of intra-oral films according to the speed Film speed (sensitivity) can be defined as the efficiency by which a film can respond to an X-ray exposure, i.e; a fast film requires low exposure time to produce a standard density image, while a slow film requires longer time of exposure to produce the same standard quality.01/25/13 00:59 Ossama El-Shall
  173. 173. or it refers to the amount of radiation required to produce a radiograph of standard density. Intra-oral films vary in speed, fast films need less X-radiation and using such films routinely plays a major role in the field of radiation protection.01/25/13 00:59 Ossama El-Shall
  174. 174. Factors affecting film speed1-Whether the film is coated only on one side with the silver halide grains (slow films) or on both sides (medium and fast films)2-The size of the silver halide grains, the larger the size, the more sensitive the film. 01/25/13 00:59 Ossama El-Shall
  175. 175. • The speed of dental X-ray films is expressed in a letter form.• Speed groups are A, B, C, D, E and F• A being the slowest film and each subsequent group being approximately twice as fast as the preceding group to give a final image of the same object with the same density.• This mean that; for example: E-speed film requires one half the exposure time of D- speed film. 01/25/13 00:59 Ossama El-Shall
  176. 176. Groups A & B are called slow films (regular).Group C is called medium speed (radiatized).Groups D & E are called high speed films (ultra- speed and ecta-speed respectively). Groups D-speed films and E-speed films are the most common intra-oral film in every day’s use. Kodak introduced E-speed plus film, this film provides the superior image quality of D-speed film at a reduced radiation exposure.01/25/13 00:59 Ossama El-Shall
  177. 177. Classification of intra-oral films according to size:Periapical and bitewing film comes in three sizes: 0 For small children (about 22 X 35mm) 1 Which is relatively narrow and used for anterior projections (about 24 X 40mm) 2 The standard film used for adults (about 32 X 41mm(01/25/13 00:59 Ossama El-Shall
  178. 178. Classification of intra-oral films.according to number of films per packetsUsually intra-oral films supply in packets containing one film. Some film packets include 2 films instead of 1. This may be helpful for record keeping, research purposes, teaching purposes, medico-legal aspects or if it is meant to control the density of each of the 2 films in a different way during processing.01/25/13 00:59 Ossama El-Shall
  179. 179. Film Processing01/25/13 00:59 Ossama El-Shall
  180. 180. Processing It is a chemical treatment, which is applied to the Exposed film to convert the invisible latent image to visible image from which useful diagnostic data can be obtained01/25/13 00:59 Ossama El-Shall
  181. 181. Latent image formation1. After film exposure, the silver halide molecules in the emulsion that become exposed will absorb the X-ray and undergo ionized.2. As a result of this ionization; minute amounts of metallic silver are formed on crystal surface & bromide is liberated.3. The degree of ionization within the crystals depends upon the amount of exposure received (latent image).4. The image remains within the emulsion till changed into silver image by chemical processing.5. In definition, the processing of the film is the process of changing of the latent image into a visible image from which 01/25/13 00:59 diagnosis can be obtained. useful Ossama El-Shall
  182. 182. Latent ImageAir/soft tissue Bone Amalgam/MetalMany x-rays Fewer x-rays Few, if any, x-rayspenetrate and ionize penetrate and not as penetrate; silvermany silver halide many silver halide halide crystals notcrystals crystals are exposed exposed01/25/13 00:59 Ossama El-Shall
  183. 183. Chemistry of processing There are five major steps of chemical processing: 1- Developing, 2- Rinsing. 3- Fixation. 4- washing. 5- drying.01/25/13 00:59 Ossama El-Shall
  184. 184. 1-DevelopingDeveloper solution treats the exposed grains (ionized). Developer solution has affinity to react with bromide part of the crystal leaving the black reduced silver grains. It consists of five elements:1-Reducing agent: It converts the exposed silver crystals into black metallic silver. It consists of Metol and Hydroquinone.2-Activator: Sodium Carbonate; it swells and softens the emulsion gelatin and provide alkalinity for the reducing agent.3-Restrainer: K. Bromide; it slow down rate of development of unexposed crystals, so it restrain the reducing agent from making the film fogged appears .4-Preservative agent: Sodium sulphate; it prevent oxidization.5-Water as dissolving agents. 01/25/13 00:59 Ossama El-Shall
  185. 185. Developing Crystal centers converted to black metallic silver Air/soft tissue Bone Amalgam/metal01/25/13 00:59 Ossama El-Shall
  186. 186. Developing (continued) Entire crystal converted to black metallic silver Air/soft tissue Bone Amalgam/gold01/25/13 00:59 Ossama El-Shall
  187. 187. 2-Rinsing With fresh water in order to 1- Neutralize the alkalinity of the developer solution 2- To stop the developer action 3- Remove the remnants of developer solution from the film01/25/13 00:59 Ossama El-Shall
  188. 188. 3-FixationIt removes the unexposed undeveloped silver bromide granules and hardens the gelatin. It consists of:Clearing agent: Aluminum thiosulfate, it clear the unexposed silver bromides.Acidifier: Acetic acid, to provide required acidity to neutralize the developer alkalinity.Hardener: Aluminum chloride, to shrinks and hardens the gelatin.Preservative: Sodium sulphate: it maintains the chemical balance of fixer chemicals.Water as a solvent.01/25/13 00:59 Ossama El-Shall
  189. 189. Fixing Unexposed crystals removed from film Air/soft tissue Bone Amalgam/metal01/25/13 00:59 Ossama El-Shall
  190. 190. 4-Washing: with water to remove all the residual processing chemicals.5-Drying: with air or dryer to makes the film finally ready for interpretation and mounting, and facilitates film handling with lesser mechanical damage.01/25/13 00:59 Ossama El-Shall
  191. 191. Latent ImageAir/soft tissue Bone Amalgam/MetalMany x-rays Fewer x-rays Few, if any, x-rayspenetrate and ionize penetrate and not as penetrate; silvermany silver halide many silver halide halide crystals notcrystals crystals are exposed exposed01/25/13 00:59 Ossama El-Shall
  192. 192. Developing Crystal centers converted to black metallic silver Air/soft tissue Bone Amalgam/metal01/25/13 00:59 Ossama El-Shall
  193. 193. Developing (continued) Entire crystal converted to black metallic silver Air/soft tissue Bone Amalgam/gold01/25/13 00:59 Ossama El-Shall
  194. 194. Fixing Unexposed crystals removed from film Air/soft tissue Bone Amalgam/metal01/25/13 00:59 Ossama El-Shall
  195. 195. Methods of processing.1. Fixed time and temperature. (Manual)2. Visual method. (Manual)3. Automatic processing:4. Polaroid land radiography.5. Inject able intra-oral films.6. Self-processing solutions contained intra- oral films.7. Film less dental radiographic tech.01/25/13 00:59 Ossama El-Shall
  196. 196. 1-Fixed time and temperature.1- It is a reliable and standardized method2- The optimal temp. is 203- The higher temp. the less time required and vice versa4- the fixed times for each step are: a- 5min developing b-15-20 sec. for rinsing c-10min. Fixation d-20 sec. washing01/25/13 00:59 Ossama El-Shall
  197. 197. 2-Visual method.1. Films are immersed in developer and removed every now and then to be checked on safe light till image is visible2. Then rinsed and fixed3. It is not standardized method as it depends mainly on human factors01/25/13 00:59 Ossama El-Shall
  198. 198. 3-Automatic processing Automatic processor is a special machine, which can perform all the steps of processing of both extra-oral and intra-oral films until the dry radiograph is obtained in about 5 minutes. The film is opened manually in a light tight compartment of the machine and then placed in its place to be automatically carried by the rollers of the machine from one step to the other.01/25/13 00:59 Ossama El-Shall
  199. 199. Advantages of automatic processor:1-Rapid and easy method2-Standardization of processing.3-No need for dark room and its equipments.Disadvantages of automatic processor:1-Highly expensive.2-Need for regular maintenance3-Need minimum amounts of films per day4-High temperature of machine tends to produce chemical fog in the radiograph and rapid deteriorates the strength of the solutions.01/25/13 00:59 Ossama El-Shall
  200. 200. Automatic Processor Drying ElementsFilm FilmEntry Exit Developing Water Fixing01/25/13 00:59 Solution Rinse El-Shall Ossama Solution
  201. 201. dr yer fi xer rin se water p er v elo s de ilm f rt in se01/25/13 00:59 Ossama El-Shall
  202. 202. Daylight Loader01/25/13 00:59 Ossama El-Shall
  203. 203. 4-Polaroid land radiography.Extra-oral films could be made using an emulsion on a paper backing instead of the usual film base.A special cassette and screen are used during film exposure by conventional dental x-ray machine.It required more exposure time but processing is a one step dry method, only 10 sec. carried out in a special electric small table top unit.01/25/13 00:59 Ossama El-Shall
  204. 204. 5-Injectable intra-oral films. In these types of processing, the processing solutions are respectively injected into the closed film packed which is supplied with an inject able sits. As processing takes place inside the packet, such film packets must have no lead foil or black paper folds. Advantage of inject able intra-oral films: 1-Easy and rapid method. 2-No need for the dark room. Disadvantage of this method: 1-Fogged image. 2-Need further fixation to avoid loosing details.01/25/13 00:59 Ossama El-Shall
  205. 205. 6-Self-processing solutions contained intra-oral films.These films contain 2 small packets attached tothe film packet. After exposure, they arepulled one after one to pour first the developerand then the fixer into the film packet. Thismethod has the same advantage anddisadvantage of the injection method.01/25/13 00:59 Ossama El-Shall
  206. 206. The Dark Room Light tight (against light leakage). Both white light and safe light illumination: The white light is used for cleaning the tanks and preparation of the solutions. The safe light is used during opining film packets and processing. Safe light specifications. Coin on film test. Processing tanks. Running water source. Timer. Either stop watch or florescent. Thermometer. Dryer. Storage space.01/25/13 00:59 Ossama El-Shall
  207. 207. Processing tanks01/25/13 00:59 Ossama El-Shall
  208. 208. Films holder01/25/13 00:59 Ossama El-Shall
  209. 209. Safelight Filters Morlite GBX-2 D-speed Intraoral, Extraoral (all films)01/25/13 00:59 Ossama El-Shall
  210. 210. KODAK LED Safelight © Eastman Kodak Company Twice as much light01/25/13 00:59 Ossama El-Shall
  211. 211. Safe lighting01/25/13 00:59 Ossama El-Shall
  212. 212. Safelight Test (Coin on film test) Problem Everything OK01/25/13 00:59 Ossama El-Shall
  213. 213. Intra-Oral Radiographic Techniques.01/25/13 00:59 Ossama El-Shall
  214. 214. 1. Techniques for Periapical radiographs.2. Techniques for Bite-wing radiographs.3. Techniques for Occlusal radiographs.01/25/13 00:59 Ossama El-Shall
  215. 215. Periapical radiographic techniques. Typical 14 Periapical film survey for adults01/25/13 00:59 Ossama El-Shall
  216. 216. 01/25/13 00:59 Ossama El-Shall
  217. 217. Typical 14 film survey for adults The central rays is targeted onto the apex; depiction of the alveolar crest is of only secondary importance.01/25/13 00:59 Ossama El-Shall
  218. 218. Periodontal 14-film survey for adults The central rays is targeted onto the alveolar crest; depiction of the root apices is only of secondary importance.01/25/13 00:59 Ossama El-Shall
  219. 219. Techniques for Periapical radiography Paralleling technique Bisecting angel technique.01/25/13 00:59 Ossama El-Shall
  220. 220. Paralleling techniqueRight angle technique Long cone technique01/25/13 00:59 Ossama El-Shall
  221. 221. Paralleling technique01/25/13 00:59 Ossama El-Shall
  222. 222. Head Position Head position for theparalleling technique isnot critical, since youwill be aligning the PIDwith the ring.01/25/13 00:59 Ossama El-Shall
  223. 223. correct incorrectIn the paralleling technique, the film is positioned in the mouth sothat the long axis of the film and the long axis of the tooth areparallel. We can not see the long axes of the teeth but, in general,all the teeth incline toward the middle of the head. Thus thefilm/instrument will almost always be tipped slightly (up or down,depending on the arch). In the illustration above right, the film isplaced straight up and down and is not parallel; the patient isunable to close completely on the biteblock and the apices of theteeth would not appear on the film. 01/25/13 00:59 Ossama El-Shall
  224. 224. Rinn XCP Paralleling Instruments ANTERIOR POSTERIOR01/25/13 00:59 Ossama El-Shall
  225. 225. 01/25/13 00:59 Ossama El-Shall
  226. 226. ?Why long cone To prevent the magnification of the image and the un-sharpness of the film due to increasing the film object distanceA parallel non-diverging x-ray beam is required, this is achieved by increase target film distance by using a long cone (16inches)01/25/13 00:59 Ossama El-Shall
  227. 227. Sharpness Measures how well the details(boundaries) of an object are reproduced on a radiograph Increased by: Source-object distance Object-film distance Film crystal size Motion will decrease sharpness01/25/13 00:59 Ossama El-Shall
  228. 228. Magnification Decreased by: Source-object distance Object-film distance01/25/13 00:59 Ossama El-Shall
  229. 229. 16” FFD image Target 16” from film Target 8” from film 8” FFD image FilmIncreasing the distance from the target of the x-ray tube(focal spot, focus) to the object (teeth/film) (FFD = focus-filmdistance) will result in an increase in sharpness and a decrease inmagnification. This results when a longer PID (cone) is used.Moving the film closer to the teeth will also increase sharpnessand decrease magnification. 01/25/13 00:59 Ossama El-Shall
  230. 230. Target-object-film relation. target Object Film01/25/13 00:59 Ossama El-Shall
  231. 231. 8" FFD 12" FFD Most newer x-ray machines have a recessed target (away from the PID). This helps to increase the focus-film distance (FFD), resulting in a sharper image and less magnification without an increase in the length of the PID (position indicating device). A longer PID is effective, but it makes positioning the tubehead more difficult.01/25/13 00:59 Ossama El-Shall
  232. 232. Object-film distance small bisecting paralleling01/25/13 00:59 Ossama El-Shall
  233. 233. Maxillary anterior region Photograph and radiograph of the region 01/25/13 00:59 Ossama El-Shall
  234. 234. Maxillary anterior region Film holder and positioning for maxillary anterior area 01/25/13 00:59 Ossama El-Shall
  235. 235. Maxillary Incisor centered on contact between film placed far back in central and lateral incisors patient’s mouth01/25/13 00:59 Ossama El-Shall
  236. 236. Maxillary canine region Photograph and radiograph of the region 01/25/13 00:59 Ossama El-Shall
  237. 237. Maxillary canine region Film holder and positioning for maxillary canine area 01/25/13 00:59 Ossama El-Shall
  238. 238. Maxillary Canine film placed against the opposite film centered on canine side of the arch, far away from the canine01/25/13 00:59 Ossama El-Shall
  239. 239. Maxillary premolar region 01/25/13 00:59 Ossama El-Shall
  240. 240. Maxillary Premolar film equidistant from lingualfront edge of film anterior to surfaces of teeth (redmiddle of canine; approximately arrows); this opens contactscentered on 2nd premolar between the teeth.01/25/13 00:59 Ossama El-Shall film in center of palate
  241. 241. Maxillary molar region 01/25/13 00:59 Ossama El-Shall
  242. 242. Maxillary Molar film equidistant from lingual film centered on surfaces of teeth (red second molar arrows); this opens contacts between the teeth.01/25/13 00:59 Ossama El-Shall film in center of palate
  243. 243. Mandibular anterior region Photograph and radiograph of the region 01/25/13 00:59 Ossama El-Shall
  244. 244. Mandibular anterior region Film holder and positioning for mandibular anterior area 01/25/13 00:59 Ossama El-Shall
  245. 245. Mandibular Incisor film positioned away fromfilm centered on midline teeth, pushing tongue back slightly 01/25/13 00:59 Ossama El-Shall
  246. 246. Mandibular canine region Photograph and radiograph of the region 01/25/13 00:59 Ossama El-Shall
  247. 247. Mandibular canine region Film holder and positioning for mandibular canine area 01/25/13 00:59 Ossama El-Shall
  248. 248. Mandibular Canine film positioned away from film centered on canine teeth, pushing tongue back slightly01/25/13 00:59 Ossama El-Shall
  249. 249. Mandibular premolar region 01/25/13 00:59 Ossama El-Shall
  250. 250. Mandibular Premolar film equidistant from lingual front edge of film anterior to surface of teeth (redmiddle of canine; approximately arrows); film placed toward centered on 2nd premolar center of mouth, displacing tongue01/25/13 00:59 Ossama El-Shall
  251. 251. Mandibular molar region 01/25/13 00:59 Ossama El-Shall
  252. 252. Mandibular Molar centered on second molar film equidistant from lingual surface of teeth; in this case the film will usually contact lingual of molars01/25/13 00:59 Ossama El-Shall
  253. 253. Bisecting angel technique01/25/13 00:59 Ossama El-Shall
  254. 254. Bisecting angel technique. X-ray beam X-ray beam perpendicular to bisecting line01/25/13 00:59 Ossama El-Shall
  255. 255. Bisecting angel technique.01/25/13 00:59 Ossama El-Shall
  256. 256. The film is positioned with the long axis vertical and thedot-end of film extending ¼” beyond the incisal edge.With the all-white side of film facing the teeth, the fingerpressure is applied at the cervical portion of the crown toavoid film bending. 01/25/13 00:59 Ossama El-Shall
  257. 257. The film is positioned with the long axis horizontal andthe dot-end of film extending ¼” beyond the occlusalsurface. With the all-white side of film facing the teeth,the finger pressure is applied at the cervical portion ofthe crown to avoid film bending. 01/25/13 00:59 Ossama El-Shall
  258. 258. Film placement, as indicated above, is the same for maxilla or mandible. The film is placed vertically for anterior teeth (canine to canine) and horizontal for posterior teeth.01/25/13 00:59 Ossama El-Shall
  259. 259. The film is held in the proper position using the thumb (maxillary anterior, above left), Index finger of opposite hand (all other areas, above right).01/25/13 00:59 Ossama El-Shall
  260. 260. Vertical angulations during bisecting angle technique Maxilla (+ve) Mandible(-ve)Incisors: 45-55 25-15Canines: 45-50 15-20Premolars: 35-40 5-15Molars: 25-30 0-501/25/13 00:59 Ossama El-Shall
  261. 261. Horizontal angulations during bisecting angle techniqueCentral rays should be parallel tointerproximal surface of the teethCentral rays should pass through the contactarea of the teeth.01/25/13 00:59 Ossama El-Shall
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  265. 265. 01/25/13 00:59 Ossama El-Shall
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  268. 268. 01/25/13 00:59 Ossama El-Shall
  269. 269. 01/25/13 00:59 Ossama El-Shall
  270. 270. Advantages of Bisecting Angle Technique•More comfortable: because the film is placed in themouth at an angle to the long axis of the teeth, the filmdoesn’t impinge on the tissues as much.•A film holder, although available, is not needed. Patientscan hold the film in position using a finger.•No anatomical restrictions: the film can be angled toaccommodate different anatomical situations using thistechnique 01/25/13 00:59 Ossama El-Shall
  271. 271. :Anatomical Variations Anatomical situations which might require:using the bisecting angle technique area shallow palatea large palatal toursa shallow or tender floor of the mouth(a short lingual frenum (tongue-tie 01/25/13 00:59 Ossama El-Shall
  272. 272. Disadvantages of Bisecting Angle Technique•More distortion: because the film and teeth are at anangle to each other (not parallel( the images will bedistorted.•Difficult to position x-ray beam: because a film holder isoften not used it is difficult to visualize where the x-raybeam should be directed.•Film less stable: using finger retention, the film has morechance of moving during placement 01/25/13 00:59 Ossama El-Shall
  273. 273. Distortion In the bisecting technique, the long axis of the toothis not parallel with the long axis of the film.This results in a distortion of the image producedusing this technique.In the left radiograph below, the buccal roots appearmuch shorter than the palatal root, even though in theactual tooth the lengths are not that much different.In the other radiograph taken with the parallelingtechnique, the lengths are projected in their properrelationship (minimal distortion(. 01/25/13 00:59 Ossama El-Shall
  274. 274. 01/25/13 00:59 Ossama El-Shall
  275. 275. Techniques for Bite-wing radiography01/25/13 00:59 Ossama El-Shall
  276. 276. Diagram of correct film position and central rays targeting in bite-wing film The paper extension from the film packet must not be pulled too much. The central ray is targeted through either the maxillary second premolar or the first permanent molar. 01/25/13 00:59 Ossama El-Shall
  277. 277. Bitewing Head Position The head should be positioned so that the maxillaryarch is parallel to the floor, both side-to-side andfront-to-back, when using bitewing tabs.01/25/13 00:59 Ossama El-Shall
  278. 278. Bitewing Film Placement Front edge anterior to Film centered on second middle of mandibular molar (if 3rd molars are canine (approximately erupted; otherwise center centered on 2 nd on contact between 1st and01/25/13 00:59 premolar) Ossama El-Shall 2nd molar).
  279. 279. The stick-on bitewing tab is always centered top-to-bottom with the film oriented horizontally (see pictureabove). The tab is placed on the Clinasept cover onthe all-white side of the film. When some teeth aremissing, the tab may be placed more anteriorly orposteriorly to allow maximum contact with the teeththat are present.01/25/13 00:59 Ossama El-Shall
  280. 280. The film is placed in the mouth between theteeth and the tongue. Hold on to the tab andinstruct the patient to close slowly andcompletely. 01/25/13 00:59 Ossama El-Shall
  281. 281. 10° positioning guideThe vertical angulationis always set at +10degrees (the tubeheadis pointing downward). 01/25/13 00:59 Ossama El-Shall
  282. 282. correct incorrectThe horizontal angulation is adjusted so that a lineconnecting the front and back edge of the PID (yellow lineabove) is parallel with a line connecting the buccal surfacesof the premolars and molars (green line above). Instruct thepatient to open their lips so that you can see the buccalsurface (see next slide). The front edge of the PID shouldbe ¼” anterior to the front edge of the film. 01/25/13 00:59 Ossama El-Shall
  283. 283. Patient opening lips (“smiling with teeth together”) to allow visualization of buccal surface of posterior teeth.01/25/13 00:59 Ossama El-Shall
  284. 284. 01/25/13 00:59 Ossama El-Shall
  285. 285. Techniques for Occlusal radiography01/25/13 00:59 Ossama El-Shall
  286. 286. Maxillary Topographical OcclusalMandibular Topographical Occlusal Maxillary Vertex OcclusalMandibular Cross-Sectional OcclusalPosterior Oblique Maxillary OcclusalPosterior Oblique Mandibular OcclusalModified Oblique Posterior Mandibular Occlusal01/25/13 00:59 Ossama El-Shall
  287. 287. Occlusal Film-Identify large lesions-Determine bucco-lingual location-View developing anterior dentition-Image patients with trismus (if panorama not available)01/25/13 00:59 Ossama El-Shall
  288. 288. Head PositionMaxillary occlusal: Maxilla parallel to floorMandibular occlusal: Mandible perpendicular to floor Film PositionCentered on area of interestAll-white side facing x-ray tubePatient bites gently on film Exposure SettingsNormal Maxillary = PA/ BWMandibular = PA/BWTrue Maxillary = 4X PA/BW01/25/13 00:59 Ossama El-Shall
  289. 289. X-ray Beam Position Centered on area of interest Vertical angulations (see below)01/25/13 00:59 Ossama El-Shall
  290. 290. Thank you all for listening Dr. Ossama El-Shall E-mail address: oelshall@hotmail.com01/25/13 00:59 Ossama El-Shall
  291. 291. Believe in yourself, for if you don’t believe in yourself, it will be hard for others to believe in01/25/13 00:59 Ossama El-Shall
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