Dental Radiography Flashcards
Which direction will a palatally/lingually positioned tooth appear to move?
I’m the same direction as the x-day tubehead
Which direction will a buccally positioned tooth appear to move?
The opposite way to the x-day tubehead
If an unerupted tooth is in the line of the arch with way will it move?
It doesn’t move
What are the clinical indications for using parallax?
To assess the position of unerupted maxillary canines, odontomes and supernumaries
How can you achieve parallax in the vertical plane?
Panoramic radiograph and an upper standard occlusal
How can you achieve parallax in the horizontal plane?
2 PA’s
One incisal and one in the canine region
How many degrees is the tubehead angled downwards for an upper standard occlusal?
65-70 degrees
Kv determines?
Quality of photons
Ma determines?
Quantity of photons
What is the maximum limit of radiation for unclassified workers ie me
6msv
What does he radiation protection file include?
Local rules
Employers written procedures
When did ionising radiation regulations 1999 come into force?
1st jan 2000
What did ionisin radiation regulations 1999 replace?
Ionising radiation regulations 1985
What areas do approximately varies effect
Medial/distal
X rays can be absorbed by human tissue
True
The photo electric effect predominates with high x-ray photon energies
False
The photoelectric effect is primarily responsible for producing contrast between different images
True
X-ray set filters are usually made of aluminium
True
Colimators restrict the x ray beam size
True
Dental xray set filters remove most of the low energy photons from the xray beam
True
Dose reduction to the patient is achieved by using long FSDd
True
Effective dose is estimated at between 0.001Sv and0.008sv
False
Effective dose is estimated at between 0.016msv and 0.026msv taking into account the salivary glands
True
Deterministic (non stochastic effects) have a high threshold
True
All surgery walls should be lead lined and coated in barium plaster
False
I’m radiographs of the maxilla the antral floor can creative a thins dense radiolaria line
True
The antrum creates a radiolucent shadow that can overlie the posterior teeth
True
When taking a parralleling PA the xray beam is aimed at 90 degrees to the image receptor
True
Bite wings involve the xray beam being aimed directly through contact points of the teeth
True
Dark film fault
Fogging
Over exposure
Over developed
In panoramic tomography the incisors will appear wide if the patient is too close
False they will appear smaller
During oblique lateral radiography beam aiming device is used to align the beam at right angles to the image receptor
False
Estimated risk of fatal cancer resulting from insta-oral radiography
1 in 10,000,000
Age group at highest risk of somatic stochastic effects
0-10 years
How should the image receptor be aligned for a parralleling PA
Parrallel to the tooth
Radiographic keyhole
Oblique lateral radiographs
How should a patient be placed within a cephalostat for a lateral ceph radiograph
So the xray beam is perpendicular with both the midline Sagittal plane and film/sensor
How many hours of cpd must radiographs complete in a five year cycle
5 hours
Which type of dose accounts for both the type of radiation used and the sensitivity of body tissues to radiation damage?
Effective dose
What is the dose for classified workers?
20msv
What is the dose limit for the general public?
1msv
Effective dose for bite wings/pa
0.003-0.022msv
Effective dose for panoramic radiograph
0.0027-0.038 msv
Effective dose for upper standard occlusal
0.008
Effective dose for lateral cephalometric
0.002-0.0056
Cancer risk of panoramic radiographs?
One in one million
