1. Principles of Dental Imaging
RVT: Chapter 10
CTVT: pg

2. Objectives: Dental Imaging
Describe the dental x-ray unit
Explain the use of dental x-rays
Understand the basics of dental film
Explain the methods for dental film processing
Know the differences between types of dental radiography

3. Why Dental Imaging? To see pathology below gingiva or inside tooth
To evaluate missing teeth
For client communication/education
Medical/legal documentation
Postoperative extraction confirmation
Follow progression of pathology or periodontal disease
Pre-purchase exams for show dogs

4. Why Do We Image Teeth?
Periodontal disease is a common ailment in small animals.
Isolating origin/extent without radiographs is difficult
The x-ray shows lesions above AND below the gum line.
Dental radiographs become part of your patient’s permanent medical record.
Survey rads are good to have BEFORE disease process begins

5. When to Take Dental Radiographs
Tooth mobility
Gingival bleeding
Nasal discharge
Oral swelling
Tooth is fractured
Tooth is discolored
Gingival recession/bone exposure is present
Teeth are missing
Prior to extraction - anatomical orientation and documentation
Post extraction
During endodontics

6. Dental Radiography: Overview
Includes both intraoral and extraoral rads
Special equipment not essential
X-ray machine
Dental x-ray machine
Allows thorough evaluation of tooth & periodontium
Remember what makes up the periodontium?
Types of dental imaging:
Film CR DR

7. Regular X-ray Machine Intraoral: Film inside the mouth Extraoral: Film outside the mouth
Regular Machine - Intraoral
Regular Machine - Extraoral

8. Dental Radiography Unit

9. Parts of a Dental Radiography Unit
X-ray Tube
Stationary anode
Advantage?
Disadvantage?
No collimator light
Can be angled directly over anatomy
Extension cone (PID)
Lead lined
Variable lengths

10. Parts of a Dental Radiography Unit
Generator/Control Panel
Contains timer and kVp/mA regulators
kVp usually pre-set around 70
mA usually pre-set at 7 or 8
Time is variable: set by operator
Should have a technique chart near the generator
Some systems have preset settings for dogs, cats, exotics

11. Radiation Safety - Dental
Technician should stand behind a barrier whenever possible…however…
Very minimal exposure to personnel when using dental machine
Why is this?
Never stand directly in front of or behind the tube head
Film should never be held in patient’s mouth while radiograph is taken
Dosimeters should be worn
Machine should be inspected annually

12. Film Imaging Intraoral film is used in dental radiography
Inexpensive, flexible, and provides good detail
No intensifying screen
Can achieve high definition with dental film due to infinite resolution
Measured in line pairs/mm
Requires higher technical factors
Film is individually packaged
No cassette or film box needed
Store away from radiation!

13. Dental Film
Individual dental films are packaged in a light-tight plastic envelope and contain:
The film
Paper folder/packing card
Lead foil backing- prevents scatter radiation from affecting film
Tab opening in back for film removal
Packets are color-coded:
Green: single film packet
Gray: two-film packet

14. Dental Film Speeds D (ultra speed) E
Used most commonly in veterinary dentistry E
Twice as fast as D film
Requires half the exposure

15. Dental Film
Sizes used most often in small animal veterinary dentistry:
Size 0 – Cats, exotics
Size 2 (standard size) – Used most
Size 4 – Larger teeth, occlusal surfaces

16. Film Dot
Dental film is embossed with a raised dot in one of the corners.
Convex side towards the beam
(White side)
Concave side away from the beam
Dot is always positioned rostral.

17. Film Processing 1. Manual 2. Automatic Chairside darkroom
Standard radiography processor
Can be used by attaching dental film to leader film
Film can become unattached and get lost…not ideal
Dental processors are available!
Efficient & consistent
Work on roller transport system
Usually not feasible unless large volume practice

18. Chairside Darkroom

19. Film Labeling & Storage
Images are part of patient’s medical record
Each image must be identified with permanent marker
Store individually in mini envelopes
Teeth must be identified correctly!
Well-processed film is of good archival quality

20. Computerized Dental Radiography
Image receptor is plastic covered, flexible phosphor plate
Will need to be replaced over time
Available in many sizes
Processing requires a reader

21. Digital Dental Imaging
Image receptor is a sensor pad that captures image and transfers it to a computer screen
Sensor is not flexible and limited on sizes

22. CR and DR Imaging Recent in veterinary medicine
(last 10 years or so)
Advantages & disadvantages similar to non-dental radiography
Can use the same x-ray unit as film
Hand held units require more training
May be cost-prohibitive (unless high volume)