3. Dental technique

Question 1

What are the terms mesial and distal used for?

Answer 1

• Describing tooth SURFACES closest to and furthest away from midline, respectively

Question 2

List 3 methods for reducing radiographic penumbra

Answer 2

• Small focal spot
• Increasing distance between object and focal spot
• Decreasing distance between object and sensor

Question 3

Using the parallel intraoral technique, what degree of obliquity is tolerated without too much distortion?

Where can we use the parallel technique in cats and dogs?

Answer 3

<20 deg

Use in MANDIBULAR caudal teeth

Question 4

Briefly, describe bisecting angle technique

Answer 4

Tube head oriented perpendicular to line drawn between plane of tooth and plane of receptor -> represents anatomy without magnification

Question 5

What does the acronym SLOB denote? Explain.

Answer 5

“same lingual, opposite buccal”

• When achieving oblique views of e.g. multirooted teeth to seperate roots, helps to determine direction in which structures move with tube head movement

Objects that move in same direction that tube was shifted are lingual/palatal; move in opposite direction are buccal/labial

E.g. left 4th premolar

Move tube distally -> root closest to source (buccal) shifts mesially, root furthest from source (lingual) shifts distally

Question 6

Explain the dot on dental films

Answer 6

• Raised dot -> oriented towards tube during exposure, then used to locate R and L properly
• When reading films, oriented so:

INTRAORAL FILMS = convex side TOWARDS reader

EXTRAORAL FILMS = convex side AWAY from reader

Question 7

Briefly, which types of radiographic film / detectors are available

Answer 7

• Film:

Pros: HIGHER RES (20lp/mm), FYI people can resolve 6 -> NEED MAG to benefit from res

Cons: Usual stuff for analog….

• Digital:

Indirect = Photostimulable Phosphor

-> Latent image transfer and erased with light

Direct = Charge-coupled device (CCD) or Complementary metal oxide semiconductor (CMOS) -> easiest and most efficient. Disadvantage related to larger detector size

Question 8

What is the near parallel extraoral technique used for?

Answer 8

FELINE maxillary 3rd and 4th premolars roots

-> Zygomatic arch anatomy results in superimposition

See pic