Radiography

Question 1

What are the 2 types of DNA mutations?

Answer 1

stochastic (chance)

Deterministic (due to increased dose)

Question 2

What is absorbed dose?

Answer 2

The actual value of radiation received in Gy

Question 3

What is the equivalent dose?

Answer 3

The type of radiation given in Sv.

Question 4

What is the effective dose?

Answer 4

Related to the tissue type which has been irradiated in Sv.

Question 5

What are the main requirements for dental x-rays?

Answer 5

F speed film/digital sensor
Use of holders and paralleling techniques
60-70kV, DC instead of AC
Rectangular collimator with open ended spacer cone and long FSD (200mm)

Question 6

What is the dental X-ray recall time?

Answer 6

High risk children 6monthly until no new caries then annually for moderate risk.
Low risk children 12-18mnths in primary dentition, 2yrs for permanent.

Question 7

What are the principles of IRMER 2017?

Answer 7

Justification: all exposures must be of diagnostic benefit
Optimisation: dose as low as reasonably practicable, maximum info for minimum exposure
Limitation: equipment in good working order

Question 8

How often should X-ray equipment be QA tested?

Answer 8

OPT and intra oral units every 3yrs.

Hand held units and CBCT every year

Question 9

What 3 duty holder positions would a dentist generally have?

Answer 9

Referrer: registered professional justifying exposure
Practitioner - registered professional to justify exposure
Operator - adequately trained to carry out x-rays

Question 10

What is the effective dose limit for classified and non classified workers?

Answer 10

Classified:
Effective dose limit 20mSv a year

Non classified:
Effective dose limit 1mSv per year
Pregnant workers <1mSv/year

Question 11

What xrays should be taken for patients with generalised pocketing 4-5mm with BPE score of 3?

Answer 11

Horizontal BWs (size 2) 
Supplemented with PAs for selected anterior teeth

Question 12

What xrays should be taking for pocketing >6mm with BPE score of 4?

Answer 12

Vertical BWs (size 0) 
Supplemented with PAs using paralleling technique

Question 13

What is the function of tungsten in the X-ray tube head?

Answer 13

Filament cathode negative and target anode positive

Question 14

What is the function of copper in the X-ray tube head?

Answer 14

It is a heat conductor of the target surround

Question 15

What is the function of lead and zinc in the tube head?

Answer 15

It is for shielding to prevent leakage

Question 16

What is the function of aluminium and zinc in the X-ray tube head?

Answer 16

Filtration as it filters the final spectrum X-ray energy

Question 17

What is the main function of lead in the collimator?

Answer 17

It is used to absorb scatter xrays to prevent image degradation and absorb primary dose.

Question 18

How can xrays be described?

Answer 18

Xrays are short wavelengths, high frequency type of electromagnetic radiation

Question 19

X-ray shows a significant amount of GP in the periradicular tissues. What is the most likely anatomical reason for this?

Answer 19

Loss of apical constriction

Question 20

You are using vertical parallax fo identify position of unerupted maxillary canine, you use opt and anterior oblique occlusal.
On comparing these the canines position on anterior oblique relative to opt the canine appears to move apically.
Where is the canine likely positioned?

Answer 20

Palatally