radiology 1

Question 1

cervical burnout

Answer 1

triangular radiolucencies at necks of teeth
happens due to to round shape of teeth beams less attenuated in these areas
will usually affect more than one tooth in a graph ,
dont confuse with secondary or root caries

Question 2

why might there be a radiopaque zone beneath amalgam restorations

Answer 2

tin and zinc ions released into underlying demineralised dentine which increases its radiodensity

Question 3

mach band effect

Answer 3

optical illusion in which contrasting areas appear brighter/ darker than they actually are
can be misleading so consider caries outlines vs uniform outlines of fillings

Question 4

radiopaque u/j shaped structure in maxillary sinus

Answer 4

zygomatic buttress

Question 5

above what teeth is the maxillary sinus seen

Answer 5

molars and premolars in maxillary jaw

Question 6

what is the y of ennis and what region is it located

Answer 6

superimposition of nasal cavity floor and border of maxillary sinus
seen in canine region

Question 7

circular radiolucencies superimposed on pulp are indicative of what

Answer 7

buccal or lingual caries

Question 8

tomography

Answer 8

allows slices of the subject/image to be views separately
dental panoramics use conventional tomography (single slice)
CT scans use computed tomography (multiple slices)

Question 9

main problem with panoramic radiographs

Answer 9

movement artefacts

Question 10

focal trough

Answer 10

band in panoramic radiography where images appear adequately sharp
curved to match shape of jaws
if focal trough to buccal = image stretched horizontal
if focal trough to lingual = image stretched vertically

Question 11

double shadows
(panoramic)

Answer 11

seen by structures near centre of rotation
captured twice even though only one e.g cervical spine, soft palate, hyoid bone

Question 12

ghost shadows
(panoramics)

Answer 12

created by structures between x ray source and centre of rotation
they appear magnified , blurry , higher up and transposed on the opposite side of their true anatomical position

Question 13

what will happen to an image if the focal trough on a panoramic is too buccal

Answer 13

if focal trough to buccal = image stretched horizontal

Question 14

what will happen to an image if the focal trough is too lingual on a panoramic

Answer 14

if focal trough to lingual = image stretched vertically