special tests Flashcards
what are radiographs?
Images created using X-ray photons which pass through an object before interacting with a receptor
what are the three types of interactions of x-rays with matter?
Transmitted (i.e. passes through unaltered)
Absorbed (i.e. stopped by the tissue)
Scattered (i.e. changes direction)
which attributes of an x-ray contribute to attenuation of x-ray photons?
absorption and scattered
what do radiographic images represent?
the pattern of attenuation of the x-ray photons after passing through matter
what do the shades of grey of an x-ray correspond to?
the types of tissues the x-ray passes through
what are the darker areas on an x-ray?
radiolucent- less attenuation of x-rays
what are the lighter areas on an x-ray?
radiopaque- more attenuation of x-rays
are the terms radiolucent and radiopaque relative or absolute?
relative
why do we use x-rays?
to show anatomy and pathology not visible to the naked eye
what is the most common use of x-rays in dentistry?
to assess caries- results in decreased radiodensity, appearing radiolucent compared to the rest of the tooth
what are examples of intra-oral radiographs?
bitewing
periapical
occlusal
what are examples of extra-oral radiographs?
panoramic
lateral cephalogram
what is an example of cross-sectional radiograph?
cone beam compound tomograph
describe bitewing radiography
side view of teeth
- shows crowns
- shows parts of roots
- shows interdental bone
- multiple images taken to reduce overlap to get a view of full teeth
what is attenuation?
stopping of photons
describe periapical radiography
full length view of particular tooth/teeth
- crown and entire root
- entire height of bone support around tooth
- one arch imaged at a time
what type of tissues are x-rays taken of?
hard tissues- in dentistry= bone and teeth
describe panoramic radiography
zoomed-out view of jaws
- entire dentition, jaws and mid-face
- can be full or sectional
- worse resolution than intra-oral
describe occlusal radiography
view of one dental arch
- maxillary or mandibular
- taken at different angles- anterior/lateral, true/oblique
- allow teeth to be seen from different viewpoints
describe cone beam computed tomography
cross-sectional imaging of teeth/jaws- 3D scan
- only used when routine dental imaging doesn’t work as more radiation, cost and lower resolution
in a radiographic assessment what should be considered together?
visual and radiographic findings
how should radiographs be arranged for viewing?
as if you were facing the patient
-Maxillary teeth along top / mandibular teeth along bottom
- Right sided teeth on left, left sided teeth on right
- Incisors towards the midline / molars towards the sides
- Occlusal planes towards the middle
what is the curve of spee?
normal anatomical curvature of the occlusal plane- normally curves upwards posteriorly
how do sinuses appear on radiogrpahs?
black
