2 - Intra-oral Radiography Techniques

Question 1

3 types of intra-oral radiography?

Answer 1

peri-apical
bitewing (horizontal/vertical)
occlusal (maxilla/mandible)

Question 2

6 types of extra-oral radiography?

Answer 2

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

Question 3

peri-apical: why are they taken? x8

Answer 3

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

Question 4

peri-apical: two techniques?

Answer 4

paralleling technique

bisected angle technique

Question 5

peri-apical paralleling technique: what facilitates positioning? receptor position? type of image produced?

Answer 5

• uses holders facilitate positioning
• receptor is parallel to tooth
• accurate/reproducible image

Question 6

peri-apical bisected angle technique: how is it carried out? is the image reproducible?

Answer 6

• can be done without a holder, is operator dependent

- image not reproducible

Question 7

describe 4 critical points when it comes to using the parallel technique

Answer 7

1. use holder to facilitate positioning
2. receptor parallel to tooth
3. x-ray beam perpendicular to the tooth
4. holders are bulky, may not be tolerable for patient; important to reduce repeats and reduce amount of doses

Question 8

why is it important to use holders to facilitate positioning?

Answer 8

allows accurate geometry of image

Question 9

why is it important for the receptor to be parallel to the tooth, and for the x-ray beam to be perpendicular to the tooth?

Answer 9

minimizes magnification of the image, brings accuracy and a reproducible image

Question 10

what are the holders used in peri-apical radiography made of? what does each component do?

Answer 10

• bite block: retains receptor
• indicator/arm rod: fits into bite block
• aiming ring: slides onto arm, establish alignment of collimator with receptor

Question 11

film-tooth relationship:
vertical plane of film should be positioned how?
horizontal plane of the film should be positioned how?

Answer 11

• vertical plane of film should be parallel to the long axis of the tooth
• horizontal plane of the film must be parallel to the dental arch under examination

Question 12

what happens if the x-ray beam is not at right angles to the tooth/receptor?

Answer 12

elongation or fore-shortening of the image occurs

Question 13

what happens if film is not parallel to the dental arch under examination?

Answer 13

image becomes distorted, unwanted superimposition is shown in the image

Question 14

things that affect image size?

Answer 14

• x-ray source (focal spot) to receptor distance

- object (tooth) to receptor distance

Question 15

3 factors to think about when positioning for x-ray to be taken?

Answer 15

• receptor position (horizontal and vertical)
• beam alignment (horizontal and vertical)
• distance

Question 16

what are some barriers to good positioning?

Answer 16

• patient’s mouth size
• gag reflex
• film size
• digital sensor’s size and shape