Special tests - radiographs Flashcards
what are radiographs
Images created using X-ray photons
how does a radiograph work?
X-ray photons pass through an object before interacting with a receptor
what are the 3 ways that x-rays interact with matter?
transmitted - passes through unaltered
absorbed - stopped by the tissue
scattered - changed direction
what two x-ray interactions contribute to the attenuation of x-ray photons
absorbed and scattered
what does the radiographic image represent
the pattern of attenuation of the x-ray photons after they pass through the matter
what does the term radiolucent mean?
darker areas on the image, less attenuation of x rays ( x - rays pass more easily)
what does the term radiopaque mean
lighter areas on the image, more attenuation of X-rays
what is a key thing to remember about radiographic terminology?
they are relative not absolute terms.
why do we use radiographs
to show anatomy and pathology that is not visible to the naked eye
what is a common use of radiographs in dentistry
assess caries in the mouth
how would a dental cary appear on a radiograph
results in decreased radio density therefore will appear radiolucent compared to the rest of the tooth
name the three categories of common radiographs in dentistry
intra-oral
extra-oral
cross-sectional
name the 3 intra-oral radiographs (different angles)
bitewing
periapical
occlusal
name the 2 extra-oral radiographs
panoramic
lateral cephalogram
name the cross- sectional radiograph
cone beam computed tomograph
what does a bitewing radiograph show?
provides a view of multiple side teeth (premolars and molars)
- crowns
- part of the roots
- some interdental bone
what is a common radiograph to take to identify caries?
bitewing (pre-molars and molars)
(easy to assess anterior teeth vs posterior teeth for caries therefore don’t need to x-ray anterior teeth)
what does a periapical radiograph show
full length view of a particular tooth/teeth
- crown and entire root
- entire height of bone support around tooth
what does a panoramic radiograph show
provides a “zoomed out” view of both mandible and maxilla.
can be “full” or “sectional”
what does occlusal radiography show
provides a view of one dental arch
either maxillary or mandibular
can be taken at different angles (anterior or lateral) (true or oblique)
what is an advantage of occlusal radiography
allow teeth to be seen from different view points
what does cone beam computed tomography show
provides cross-sectional imaging of teeth/jaws “3D scan”
when would cone beam computed tomography
only used when routine dental imaging cannot provide the require information
why is cone beam computed tomography not commonly used
- increases radiation dose, decreases resolution and increases cost
how should radiographs be arranged for viewing
position radiographs as if you were facing the patient
how would you identify mandible and maxillary teeth from a bitewing radiograph
maxillary tooth would show 3 roots.
what is the curve of spee
Normal anatomical curvature of the occlusal plane
curves upwards posteriorly
what are non dental anatomy to help identify maxillary teeth
maxillary sinus
nasal cavity
maxillary tuberosity
what are non dental anatomy to help identify mandibular teeth
interior alveolar canal
mental foramen
inferior border of mandible
external oblique ridge
Mental foramen lies below premolars
