Exam 1.1: Intraoral Radiography Flashcards
What are the 3 types of images taken with the film inside the oral cavity?
PA
BWX
Occlusals
What are three criteria for PAs
Include entire tooth and 2-3 mm of apical bone
Minimal distortion
Adequate constrast/density
What are some criteria for a diagnostic BWX
Open interproximal areas
Equal distribution
What are the 2 types of images taken with film outside the mouth?
Pan
Ceph
What are the 4 “Special” types of radiographic images
MRI
CT
Ultrasound
CBCT
What is the best beam geometry possible?
Anatomy and film parallel to each other with the beam perpendicular to both
What can affect the size of the tooth on the image?
distance between the film and the anatomy
If you want to magnify the image, would you move the film closer to the tooth, or further away?
Further away
So why do we want the film as close to the anatomy as possible?
So that the tooth is very close to its actual size
What happens when you move the xray source away from the film?
Smaller anatomy and sharper detail
What happens to the image when the vertical angulation is off?
Foreshortening
Elongation
What happens to the image when the horizontal angulation is off?
Distortion in the horizontal dimension
Superimpositon/overlapping of anatomy
What can cause the same image distortion as horizontal angulation error?
Teeth out of alignment
What is the first film placement technique of choice?
Paralleling Technique
What axis is the film placed parallel to in the paralleling technique?
The true axis, not just the clinical crown
What is the only region of the mouth that you can physically touch the film to the teeth being imaged?
Posterior mandibular
What are the advantages of the paralleling technique
Minimized geometric distortion
True anatomic relationships
Minimized magnification
What are three disadvantages of the paralleling technique
Object-film distance
Can be difficult to place for views of 3rd Molars
Tough with short palatal vaults
When is it ok to use the bisecting angle technique instead of the paralleling technique?
Only in certain situations, most commonly when the patient cannot tolerate the paralleling technique
How is the beam aimed when using the bisecting angle technique?
Beam is directed perpendicular to a line bisecting the angle formed by the long axis of the tooth and the plane of the film
What type of distortion occurs when using this technique
Foreshortening due to the film being pulled against teeth which alters the object to film distance along the true axis of the tooth
Where does most of the distortion occur when using the bisecting angle technique…the crown or the root apicies?
Crown
What are some advantages of the bisecting techniqe
Avoids gag reflex Avoids tongue Avoids tori Usable in short vaults Capture long apicies
What are the disadvantages of the bisecting technique?
Inherent distortion
Difficult to place properly
Limited clinical application
How many films are in an FMX?
18
14 PAs
4 BWX
Why would a FMX be ordered?
Rampant caries or the evaluation of bone levels
How many teeth must be in contact with bite block when taking PAs
At least 2
What teeth must be included in a maxillary molar PA?
The molars (or molar area if teeth are missing) and the distal of the 2nd premolar if possible
For a Maxillary Molar PA how would the film be placed for using the paralleling technique?
Film in midline and pushed all the way back
What size film would be used for a maxillary molar PA
2
When taking a Maxillary Molar PA what bone might get superimposed over the maxillary sinus?
Zygoma
How can you differentiate between the Zygoma and the Sinus when they are superimposed
The zygoma will be horse shoe shaped and will be more radiopaque then the sinus
What number film should be used for the maxillary Premolar PA
2
Besides the teeth, what anatomical structures are sometimes visible on the Mx premolar PA
Lower border of maxillary sinus and the zygoma
What size film should be used for the maxillary lateral/canine PA
1 Vertically
Why is there a large amount of object to film distance for the maxillary Lateral/Canine PA?
The film must be pushed far enough from the teeth to avoid the curve of the palate
What size film do you use for the Maxillary Central Incisor PA
1 Vertical
Is there a large or small object to film distance for the maxillary central PA
large
Besides the teeth, what anatomy may be visible on the maxillary central incisor PA
Floor of nasal passage Incisive canal Nasal septum Shadow of the tip of the nose Lip line
What film is used for the mandibular molar PA?
2 Horizontal
What is unique about the film placement for the mandibular molar PA?
The film can be placed up against the tooth for the best possible image, if the patient can tolerate it
What film is used for the mandibular premolar PA
2 Horizontally
But 1 vertical is ok if the patient can’t tolerate the first option
What tooth structure needs to be captured on the mandibular premolar PA?
Premolars and the distal of the canine
What is unique about the Mandibular Premolar PA in terms of what film can be used?
Only region of the mouth where two types of film can be used to get the proper image
What size film is used for the mandibular premolar/canine PA
1 Vertical
What do you try to center on the film for the mandibular canine/premolar PA?
The canine and the premolar (no distal of lateral needed)
What teeth are captured in the mandibular central PA?
23-26
Besides the teeth, what anatomy can sometimes be seen in the mandibular central PA?
Genial tubercle and lingual foramen
Lip line
nutrient canals
What size film is used for the molar BWx’s
2 Horizontal
What teeth/surfaces should be captured by the molar BW?
All 3 molars/spaces
Plus the Distal of the 2nd Premolar
Besides the crown, what part of the periodontium is important to capture in any bitewing image?
Alveolar bone levels
What size film is used for the premolar bitewings?
2 Horizontal
What teeth/surfaces should be captured for the premolar BW?
Distal of both canines
Both premolars
All of First Molar
Some or All of 2nd Molar
