Techniques m3

Question 1

What are the Intra-oral x-rays?

Answer 1

• peri-apical
• bitewing - horizontal and vertical
• occlusal - maxilla and mandible

Question 2

What are Extra-oral x-rays?

Answer 2

• dental panoramic tomogram -DPT
• lateral cephalogram
• postero-anterior mandible
• lateral oblique mandible
• occipito-mental views of facial bones

Question 3

Why would you use a Peri-apical?

Answer 3

• detect apical inflammation/infection to include cystic changes
• assess periodontal problems
• trauma-fractures to tooth and/or surrounding bone
• tooth morphology pre extraction
• presence/position of unerupted teeth
• endodontics
• pre/post apical surgery
• evaluation of implants

Question 4

what are the 2 tachniques to 2 teachiques used to take a radiograph?

Answer 4

• Paralleling technique
• Bisected angle technique

Question 5

What is the difference between Paralleling technique and Bisected angle technique?

Answer 5

Paralleling

• Uses holders to facilitate positioning
• Receptor parallel to tooth
• Accurate/ reproducible image

Bisected angle

• Can be done without a holder
• Operator dependent
• Not reproducible

Question 6

Why is Paralleling the technique of choice?

Answer 6

1. Uses holders to facilitate positioning
2. Allows accurate geometry of image
3. Receptor parallel to tooth
4. X-ray beam perpendicular to tooth/receptor
5. Minimises magnification
6. Accurate/reproducible image
7. Holders are bulky and may not be tolerated by patient. Can reduce dose to patient by reducing repeats and does not expose patients fingers (see bisected angle)

Question 7

what are holders made up of?

Answer 7

• A bite-block - retains the receptor
• an indicator arm/rod - fits into the bite-block
• an aiming ring-slides onto the arm to establish alignment of collimator with receptor

Question 8

What are the 2 types of receptors?

Answer 8

Film and Digital

Question 9

What is the receptor-tooth relationship?

Answer 9

• The vertical plane of the film should be positioned so that it is parallel to the long axis of the tooth/teeth.
• The horizontal plane of the film must be parallel to the dental arch under examination

Question 10

How should X-ray tube position for vertical angulation be set up and what can happen if it is not set up right?

Answer 10

xray beam should be at right angles to the tooth/receptor

Question 11

How should X-ray tube position for horizontal angulation be set up and what can happen if it is not set up right?

Answer 11

Xray beam 90^o to Receptor

Question 12

What are thinga that affect image size?

Answer 12

1. X-ray source (focal spot) to receptor distance
2. Object (tooth) to receptor distance

Question 13

What are some barriers to good positioning?

Answer 13

• Mouth size
• Gag reflex
• Film size
• Digital sensor size and shape

Question 14

What are the 4 most common film/PSP receptor sizes?

Answer 14

1,2,3,4

Question 15

What are the problems in each of these xrays?

Answer 15

Question 16

What Film size would you use for Periapicals?

Answer 16

Adult

Anterior – “0”, “1” “2” – bisecting angle

Posterior – “2” only

Child

Anterior – “0”

Posterior:

• Deciduous – “0”
• Permanent – “2”

Question 17

What Film size would you use for Bitewing - vertical or horizontal?

Answer 17

Adult – “2” only

Child – over 10 – “2”

Child – under 10 – “0” or “1”

Question 18

For clinical knowledge where is the “controlled area”?

Answer 18