Radiographic Techniques Flashcards
Paralleling
Film/sensor placed parallel to long axis of tooth
Vertical angulation with central ray directed perpendicular to film and long axis
Horizontal angulation through the contacts
Bisecting Technique
Head position occlusal plane parallel to the floor
Film/sensor placed on an angle against the incisal edge of the teeth
Vertical angulation with central ray perpendicular to the imaginary bisector
Horizontal angulation through the contacts
Film placement-center film/sensor behind region to be radiographed
Vertical Angulation – standardized
Horizontal Angulation – through contacts
Bisecting Technique
Paralleling Advantages and Disadvantages
ADVANTAGES
Minimal distortion
Tooth and film easy to see and direct x-ray beam appropriately
Many film holders (XCPs)
DISADVANTAGES
Parallel film/sensor placement difficult in some patients
small mouth, low palatal vault, presence of tori, gag reflex
May cause patient discomfort
Bisecting
ADVANTAGES
Film/sensor placement easier in some patients
small mouth, low palatal vault, presence of tori, gag reflex
DISADVANTAGES
More dimensional distortion
Estimating location of imaginary bisector may be difficult
Center film/sensor to the midline
“Key contact”-between central incisors
Contacts to open: mesial and distal of central incisors
Apex of central incisors including 2mm of bone surrounding
Crowns of central incisors
Central Incisor Region
Center film over canine
“Key contact”- open contact between canine and lateral incisor
Contacts to open: mesial of the canine
Apex and crowns of teeth visible including 2 mm of bone surrounding
Note: Distal contact of canine will almost always be closed
Canine Region
Position film so that at least the distal of the canine is seen on the film
“Key contact”- open contact between first and second premolar
Contacts to open: mesial and distal of both premolars
Apex and crowns of teeth visible as well as 2mm bone surrounding
Premolar Region
Position film so second molar is centered on the film or the anterior edge of the film is close to the mesial of the first molar (different than book)
“Key contact”- open contact between first and second molar
Contacts to open: mesial and distal of all molars pictured
Apex and crowns of teeth visible as well as 2mm surrounding
*it is not necessary to see the mesial of the first molar on a molar film because will be on the premolar film
Molar Region
it is not necessary to see the mesial of the ___ molar or distal of the second premolar on a molar film because will be present on the premolar film
1st
Tips to determine Vertical Angulation Errors
Look for extreme cusp separation
Check the same tooth on the opposite side of the mouth and compare size
Maxillary molar projection- lingual root will appear larger and buccal roots will appear smaller
Mandibular anterior projection-will often see the border of the mandible in the film
A placement error can be any of the following
A placement error can be any of the following
Missing crown areas
Mark as an error, but only retake if half or more than half of the crown area is missing
Missing apex
Always needs a retake unless you can see on a different film
Not far enough forward
Not far enough back
Note: shade the area of the box that indicates the direction the film should be placed to correct the error
Note: shade the area of the box that indicates the direction the film or tooth should be placed to correct the error
film
Ultimate Goal of FMX
All contacts open at least once in series
All apices visible at least once in series
2 mm surrounding tooth area at least once
All incisal edges visible*
When the second molar is centered on a molar film and you still don’t have the entire third molar, you do not need a retake, you need a
supplemental film.
