Intraoral Radiographs

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Intraoral Radiographs
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Introduction

• In order to see what is the state of a patients
  oral cavity, then dental radiographs are
  performed.

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• Why Radiology?
• To see pathology hiding below the gingiva or
  inside the tooth
• Evaluate an area where the teeth appear to be
  missing
• To document the obvious - supporting treatment
  decisions
• For client communication
• Medical/legal documentation
• Postoperative confirmation of proper extraction
• Preoperative, intraoperative, and postoperative
  endodontics
• Follow progression of pulpal pathology and/or
  periodontal disease
• For prepurchase exams on show dogs to see if the
  proper number of teeth exist

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Documentation

• Periodontal disease is the most common ailment in
  small animals.
• The x-ray shows lesions above and below the gum
  line.
• Legal uses of radiographs to support treatment
  decisions prove invaluable.
• The dental radiograph becomes part of your
  patients permanent medical record. Examining
  serial radiographs of periodontal or endodontic
  cases taken at three to six-month intervals
  provides invaluable information concerning
  progression or resolution of disease.

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X-rays help us determine whether extractions are
necessary.
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When to take a Radiograph

• When a tooth is mobile
• When gingiva bleeds with or without probing When
  a tooth is fractured (either enamel, dentin, or
  pulpal exposure)
• When a tooth is discolored (pulpitis)
• When furcation exposure is present (periodontal
  disease)
• When teeth are missing without explanation
• When a feline ondoclastic resorptive lesion
  (FORL) is noted.
• Prior to extraction for anatomical orientation
  and documentation

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Anatomy of Intraoral Radiograph Machine

• Position Indicating Device (PID) - is an
  extension placed on the tube head at the
  collimator attachment. To minimize the amount of
  radiation exposure, the PID is lead lined. The
  shape of the PID may be circular or rectangular..
• Arm - the connection between the x-ray tube and
  control pannel.
• Control Panel - contains timer, kilovoltage, and
  / or milliamperage regulators.
• Electric timer-as a safety device, the timer
  operates only while the switch is being depressed
  and automatically cuts off electric current at
  the end of the exposure. The timer resets itself
  after each exposure.

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Tooth Film Distance

• When utilizing intraoral technique, film is
  placed parallel to the palatal or lingual tooth
  surface.
• Due to small animal oral anatomy this is not
  always possible. Instead, a bisecting angle
  technique is used resulting in a 20-50 degree
  angulation of the x-ray beam to the film plane,
  depending on which tooth is radiographed

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Rules for Successful Positioning

• The closer the object being radiographed is to
  the film, the sharper and more accurate the
  image.
• Use the longest film focal distance practical
• Direct the central ray as close to a right angle
  (or bisecting angle) to the film as possible
• Maintain as parallel interface between the film
  and object as possible

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Proper positioning for a radiograph of the
mandibular premolars and molars.
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Positioning for a study of the mandibular
incisors and canines.
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Positioning for the rostral mandibular premolars.
This can also be used to obtain a lateral view of
the incisors and canine tooth.
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Notice that the incisor teeth are missing!
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Positioning for the maxillary incisors.
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Maxillary incisors!
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Positioning for a study of the maxillary
premolars. This can also be used to obtain a
lateral view of the maxillary incisors and canine
tooth.
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And heres the result!
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Digital imaging dental radiology

• Digital imaging is a recent technical advancement
  in dental radiology. It will be as popular or
  even replace, film-based imaging in the future.
• Computer image capturing and image enhancement
  has many advantages compared to the traditional
  film systems. With digital imaging, the dental
  radiograph machine is still used to expose the
  lesion, but instead of film, a sensor pad is
  placed inside the mouth, accepts the image, and
  transfers it to the computer screen.

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Film

• Small intraoral film is used in dental
  radiography. It is inexpensive, flexible, and
  provides great detail. Non-screen film is
  preferable due to the high definition necessary
  to interpret dental lesions. Dental film is
  conveniently used for intra or extra-oral
  placement.
• Individual dental films are packaged in a light
  tight packet that is made of either plastic or
  paper. Inside the packet, film is positioned
  between an inner lining of two sheets of black
  paper. A sheet of lead foil is located at the
  "back" of the packet, next to the tab opening.
  Lead foil protects the film from secondary
  radiation, which may cause the film to fog

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Film Continued

• The back of the packet has a tab opening used to
  remove film for processing. This side is placed
  next to the tongue or palate.
• Intraoral dental film is packaged singly or with
  two films per packet. When two films are exposed,
  the practitioner may use the second film to give
  to the client or referring veterinarian. Film
  packets are color-codedgreen indicates a single
  film packet, gray a two-film packet.

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Components of intraoral dental film.
Water-resistant wrapper
Dental film
Lead foil
Black paper
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Film Speed

• Commonly used dental film is available as speed D
  (ultra speed) and speed E (ekta speed). Speed E
  film is rated at twice the speed of D film,
  requiring half the exposure, with small loss of
  quality.
• Ultra speed is used predominantly in veterinary
  dentistry.

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Film Sizes

• Three sizes of dental film are frequently used in
  veterinary dentistry
• child periapical size 0 measures 7/8 x 1 5/8
  inches-used mostly in cats, exotics, and small
  dogs
• Adult periapical size 2, also called standard
  size measures 1 ¼ x 1-9/16 inches. Size 2 is the
  most popular size used.
• Occlusal size 4 measures 2 ¼ x 3 inches. Occlusal
  film used to radiograph larger teeth and survey
  studies

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Film Dot

• Dental film is embossed with a raised dot in one
  of the corners. The convex side of the dot
  indicates front side of the film. The dot is used
  to identify right from left. The convex (raised)
  dot is placed at the occlusal edge and toward the
  x-ray tube. The concave (depressed) dot is placed
  toward the tongue or palate.
• To determine whether a film is on the right or
  left side, imagine where the convex dot is
  located, and identify the progression of teeth
  from incisors to molars.

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Radiographic Landmarks

• It is important to be able to look at a film and
  identify the area exposed.
• Maxillary incisors will show a large radiodense
  (white area) distal to the teeth, with two ovals
  representing the nasal area. All incisor teeth
  have one root
• Mandibular incisors - look for a black space
  separating mandibular rami
• Maxillary premolars and molars - look for a
  fine while line representing the maxillary recess
  apical to the roots
• Mandibular premolars and molars - look for
  radiolucent (black areas) above and below the
  jaw. Other than the first premolar (in the dog)
  and third premolar (in the cat), all mandibular
  premolars and molars have two roots

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It is important to know how many roots each tooth
has. Can you think of any reasons why?
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Positioning of Film and Patient

• Place film inside the mouth, parallel to the
  teeth to be examined.
• Bisecting angle technique is used in most
  exposures. Lay film far enough inside the
  animals mouth so that its root structure will be
  projected on the film. Imaginary lines are drawn
  along the long axis of the tooth and the plane of
  the film. The point where these two lines meet
  will create an angle. Instead of aiming the
  central beam perpendicular to the film as in the
  parallel technique, the central beam is aimed
  perpendicular to the line bisecting the angle
  created between the line of the tooth and line of
  the film

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Bisecting Angle Technique this minimizes image
distortion and produces an accurate image of the
canine teeth on the dental film.
In any 90 degree arc, there is one angle that
will allow an x-ray beam to cast an accurate
shadow of the tooth on the film.
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• Bisecting Angle Find the middle of the long
  axis of tooth and film.
• You now want to use the BA and x-ray head to
  create a 90 degree
• angle, no larger, no smaller.
• This takes practice, patience and time.

Tubehead on x-ray machine
Distance between the tooth and the film.
Film
CTVT pg. 888
CTVT pg. 888
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This angle will make the tooth appear short on
the x-ray film.
Tube head
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This angle makes the tooth appear longer on the
x-ray.
Tubehead On X-ray machine
FILM
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Film Processing

• Film may be developed
• By hand with regular or rapid dental processing
  solutions in the darkroom
• With Chairside developer - a portable light safe
  box with developer, fixer, and water in small
  containers. Putting your hands through two
  diaphragms in a lighted room accesses the
  solutions. The boxs top, an orange or red
  Plexiglas safety filter, enables you to see
  inside. The whole process from opening the film
  packet to examination of a rinsed film takes
  approximately one minute
• Automatically Film is placed into one end of the
  automatic dental processor and comes out fully
  developed, fixed, and dried in 2 to 7 minutes.
  Using standard veterinary automatic processors
  are discouraged because small dental films may
  become lost in the processor, and tape used to
  attach to larger films, may harm the processors
  rollers
• Instant dental x-ray film (Veterinary dental film
  system VDFS-Hawaii Mega-cor, Inc. Aiea, Hawaii)
  develops in 30 seconds within the film packet
  after infusion of developer and fix solutions

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Steps for manually processing dental x-rays

• Once the film packet is in a light secured area,
  open the packet tab on the packet and slide
  forward the paper liner and film. This will
  present film to be processed.
• Only touch the sides of the film with your
  fingers
• A film hanger is attached to the film. Film
  should extend horizontally from the clip. Give
  the film a gentle tug to make certain it is
  firmly attached to the clip
• Place the film into the developing solution for
  10-30 seconds (depending on room temperature -
  longer time if less than 68 degrees)
• The film is rinsed in distilled water for 10
  seconds Place the film in the fixing solution
  for 30 seconds
• Rinse for 30 seconds in distilled water After
  viewing, the film is placed in the fixer for 5
  minutes and a distilled water rinse for 20
  minutes
• When rinsing is complete, hang the radiograph on
  a rack to dry or use a hair drier for rapid
  drying
• Chemicals should be changed at least once weekly.