Topic 4: Dental Radiology Techniques

Question 1

What are the indications for taking dental radiographs

Answer 1

Before and after extractions 
Periodontal disease
Discolored teeth
Fractured teeth
Gingival ulcers
Missing teeth (Evaluate an area where the teeth appear to be missing)
Malocclusions causing trauma
Malformed teeth
Tooth resorptions or root resorptions
Pet dropping food
Foul odor in mouth
Reluctance to eat
Reluctance to eat chews
Nasal discharge

Question 2

What are the medical indications for taking dental radiographs

Answer 2

To document the obvious - supporting treatment decisions
Preoperative, intraoperative, and postoperative endodontics
Endodontics: dental speciality concerned with the study & tx of dental pulp
Follow progression of pulpal pathology and/or periodontal disease

Question 3

What are the legal indications for dental radiographs

Answer 3

Part of the file/ Legal documentation
For client communication
For prepurchase exams on show dogs to see if the proper number of teeth exist

Question 4

What are the practice management/economical reasons for doing dental radiographs

Answer 4

Dental radiology pays for the expensive “toys” that don’t pay for themselves…
…” Or “ we are losing money by not taking intraoral x-rays!“
Because it is a diagnostic tool
We found lesions – we treat them!

Question 5

Describe the dental X-ray machine

Answer 5

Provides the X-ray source
Portable or wall-mounted
Portable
Floor trolley (less user friendly
Hand-held dental x-ray unit
KVp and MA settings are fixed
Usually 50-70 KVp
mA is fixed (8-10)
Can use regular rad machine, but film-focus distance is only 30-50 cm
Better to use dental machine

Question 6

What is the one exposure variable for the dental X-ray machine

Answer 6

time in seconds

Question 7

What are two types of dental radiology

Answer 7

dental standard radiology

digital dental radiology

Question 8

What are the two types of digital dental radiology

Answer 8

indirect (CR)

direct (DR)

Question 9

Describe dental film

Answer 9

Small & flexible
Non-screen film
Size 0, 1, 2 (periapical), size 4 (occlusal)
Non screen film
Single emulsion
Speed: D (ultra) E, F(EKTA) 
E, F: lower detail
D: commonly used

Question 10

Why is the dental film in an envelope

Answer 10

to protect it from light exposure

Question 11

why does the dental film contain a layer of lead foil

Answer 11

to absorb scatter radiation

Question 12

Why does the dental film have a dot

Answer 12

to let you know which side is to be placed rostrally. So you can always tell right from left

Question 13

How do you develop X-ray films

Answer 13

Chairside darkroom
Developing solutions
Film clips

Question 14

Describe indirect dental radiology

Answer 14

Use photo-stimulable phosphorplates (PSP)
Place in plastic holders
Exposed and then digitally scanned
Flexible, reusable plates or sheets instead of film
After exposure, plate→ scanner → latent formed image is retrieved point-by-point → digitized (laser light scanning)
The digitized images are stored and displayed on a computer screen.

Question 15

What are the advantages to the indirect digital dental radiographs

Answer 15

Sensor plates size 0,2, 4, (6)
Flexible
Long used-life
Not expensive to replace

Question 16

what are the disadvantages to indirect digital dental radiographs

Answer 16

Sensor plates must be removed from mouth to get the image
More time than direct
Image quality questionable
Keep away from direct light while scanning

Question 17

Describe direct digital dental radiography

Answer 17

Sensor (CCD-Type or CMOS)
2 sizes (1 & 2)
Rigid, relatively thick
Connect to a computer with appropriate software (by wire or WIFI)

Question 18

What are the advantages to direct digital dental radiology

Answer 18

FAST!
Do not have to remove sensor to get the image
Better quality image

Question 19

what are the disadvantages to direct digital dental radiology

Answer 19

Disadvantages:
Small sensor size
Difficult to fit into small mouths
Fragile!
Expensive	
Only the sensor 8000$ (2012)

Question 20

What are the methods for radiology safety for dental xrays

Answer 20

Proper tube angle is important
Distance from the tube: 6 ft
Apron, thyroid lead protector
Dosimeter

Question 21

What is the intra-oral dental X-ray technique

Answer 21

intra-oral techniques:

Film positioned inside the mouth

Question 22

Describe the intra-oral dental X-ray technique

Answer 22

Patient can be left on lateral recumbency (as it is during the dental cleaning OR moved on dorsal or ventral recumbency

Question 23

Describe the parallel technique

Answer 23

Film is placed parallel to the long axis of the tooth

Central beam is directed perpendicular to the film

Question 24

What happens when the beam is angled too vertically when using the bisecting technique

Answer 24

foreshortened

Question 25

what happens when the beam is angled too horizontally when using the bisecting technique

Answer 25

lengthened

Question 26

How do you get the perfect image representation of the tooth using the bisecting technique

Answer 26

If the primary bean is aimed at 90 degree to a bisecting angle, the image will be a true representation of the tooth!

Question 27

When you’re taking an X-ray of the front tooth (maximally and mandibular incisors and canines) using the bisecting technique

Answer 27

view the animal from the side

Question 28

when you’re taking an X-ray of the side tooth (maxillary molars and premolars) using the bisecting technique

Answer 28

view the animal from the front

Question 29

How do you take a picture of all three roots in one picture

Answer 29

the parallax effect