Bitewing Radiography and Paralleling Periapical Radiography Flashcards
what are the benefits to intra oral radiographs
high spatial resolution, minimal superimposition of other anatomy, fast exposure, low radiation dose per image
what are the downsides to intra orals
limited to imagining of small areas, relatively invasive for patient, relatively difficult technique
what are size 0 receptors used for
anterior periapicals
what are size 2 receptors used for
bitewings and posterior periapicals
what are size 4 receptors used for
occlusals
what is projection geometry
positioning of all the components involved in taking a radiograph
how do you reduce magnification in an x-ray
position receptor closer to the subject
what makes an image shorter
if the subject is not perpendicular to x-ray beam
what makes an image longer
if receptor is not perpendicular to x-ray beam
how do you achieve the best possible projection geometry
maintain sufficient focus to skin distance
position receptor as close to tooth as reasonably possible
ensure receptor is as stable as possible in the mouth
use image receptor holders with a beam aiming device
keep patient still
what does a longer focus to skin distance do
reduce magnification of image
what should focus to skin distance be for intra oral units
at least 200mm
how is focus to skin distance maintained
using a spacer cone
where is the focus to skin distance measured from
x-ray source
what is the function of receptor holders
aid positioning
what does the receptor support on the holder do
helps keep receptor upright and prevents receptor bending
what does the bite block on holder do
helps stabilise holder
what does the beam aiming device on holder do
helps ensure beam is perpendicular to subject/receptor
what do bitewings aim to show
premolars and molars, maxillary and mandibular teeth, interdental bone, minimal overlap of teeth
what teeth are bitewings used for
posteriors only
what are the indications for bitewings
detection/monitoring of caries
assessment of dental restorations
detection/monitoring of periodontal bone loss
how many bitewings should you take per side
ideally 1 but maybe 2 to avoid overlap
what is the curve of spee
the curve made between maxillary and mandibular teeth on a bitewing radiograph
what do paralleling periapicals aim to show
1-4 teeth, only maxillary or mandibular, entire crown and root, alveolar bone, nearby anatomical structures
