Simplified Positioning for Dental Radiology

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Dental Radiology “CHEAT SHEET”
Area imaged General Technique and Tips
Lower PM and M Place film in vestibule between the tongue and teeth. The beam is
angled perpendicular to film. This is the only “parallel technique”.
Lower incisors +/- Canine Start by aiming beam on ventral midline perpendicular to the film.
Then tip the tube head forward 20 degrees so the beam is angled 20
degrees caudally. If desired, using larger film will allow
visualization of the lower canines on the same film.
Upper incisor Start by aiming beam on the dorsal midline, perpendicular to the
film. Then tip the tube head forward so the beam is angled 20
degrees caudally.
Upper canines Start by aiming beam dorsally over the top of the canine, similar to
the upper incisor view. Then tip the tube head 20 degrees forward
and 20 degrees to the side. This will move the image of the root
away from the premolars. The film should slightly overlap the tip
of the crown forward and to the side.. Excessive film sticking out of
the mouth is wasted. The forward tipping elongates the tooth, while
the lateral tipping serves to move the canine tooth away from the
overlapping premolars.
Upper PM and M Place the film mostly over the palate. Start dorsally over the top of
the target teeth. Tip the tube head 45 degrees to the side of the face.
Cats require a modified technique to avoid superimposition of the
Zygomatic Arch. The film is placed diagonally across the mouth
from the inside of the maxillary teeth on the side opposite that to be
imaged, to the inside of the mandibular teeth on the side to be
imaged. Position the patient so that the target teeth are on top and
the teeth line up parallel to the table top. Start the beam lateral to
the maxillary premolars, and tip the tube head 20 degrees over the
top of the nose. Tipping too little cuts off part of the target teeth
from the edge of the film. Tipping too far accentuates the
Zygomatic Arch.

“Three Simple Rules”

All positioning errors involve the three parameters of tube angulation, tube position and film position. Three simple rules serve to identify and correct any errors.

  1. If the image is foreshortened or elongated, adjust the tube angle. To make the roots longer, move the tube head more laterally.
  2. If you cut the target off at the edge of the beam (cone cut), simply move the beam over toward the area of cone cut.
  3. If you cut the target off at the edge of the film, move the film over toward the area you cut off.

The following pictures show film placement, starting position of the beam and appropriate  tipping of the beam to image the five different areas of the mouth. These diagrams are best used in conjunction with the positioning “Cheat Sheet” above. When performed as indicated, these simple positioning guidelines will provide well-positioned dental films.

Positioning for mandibular premolars and molar

Positioning for mandibular incisors and canines

Positioning for maxillary incisors

Positioning for maxillary canine

Positioning for maxillary premolars / molar

Positioning for feline maxillary premolars and molars, using the “near parallel technique”

Positioning for feline maxillary premolars and molars, using an extraoral technique

Beam angulation used to separate overlying structures.

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