The document discusses the importance of dental radiology for veterinary practices, as radiographs can reveal up to 50% more pathology than clinical oral exams alone and are necessary for accurate diagnosis, treatment planning, and monitoring of conditions like periodontal disease and tooth resorption. Proper radiographic techniques like the bisecting angle method are outlined to minimize distortion and avoid overlapping structures. Interpreting dental radiographs requires understanding orientation, anatomy, and comparing features between sides to diagnose normal versus abnormal findings.

1. Dental Radiology Workshop
Dr Christine Hawke
Veterinary Dental Consultant
29th April 2012

2. Would you do orthopaedics without rads?
At least 2/3 of each tooth is below the gumline and not
visible without radiographs!

3. Why is dental radiology so important?
• For diagnosis of pathology
– In animals with abnormal findings on clinical oral examination, full
mouth radiographs showed other undetected pathology in 50% of
dogs and 53.9% of cats.
– In those with no clinical findings, radiographs showed clinically-
important pathology in 27.8% of dogs and 41.7% of cats
Verstraete et al. Am J Vet Res 1998 59: 692-5
• For treatment planning, monitoring, follow-up and screening

4. Make the most of the opportunity!
• Many owners are concerned about the
anaesthetic, and the cost associated
with dental treatment
• We need to be thorough when we have
the opportunity to assess and treat the
mouth, so we can do everything that is
needed to remove infection and relieve
pain

5. Lamina lucida (PDL)
Alveolar bone
Lamina Dura
(Crestal bone)
Pulp
Cementum
Enamel
Dentine

6. Everyday dental radiology
 Periodontal disease is the most common condition we see in small animal
practice, and the real action is happening below the gumline

7. Assessing periodontal disease
 Looks can be deceiving…….
http://www.avds-online.org

8. Dental extraction planning

9. Tooth resorption
Very common in cats, and very painful
 Radiographs are critical for assessment and
treatment planning
 Retained roots
 Resorbing roots

10. Missing teeth

11. Missing teeth

12. Fractured teeth

13. Discoloured teeth

14. Periapical lucencies - normal or not?
 Look for the lamina lucida (PDL)
 Compare with the contalateral side
 Correlate with clinical presentation
 Crown integrity, discolouration, transillumination etc
 Monitor radiographically

15. Periapical lucencies - normal or not?
 Compare with contralateral side

16. Worn teeth

17. Oral tumours and swellings
Courtesy Dr A Caiafa

18. Interpreting dental radiographs
 Orientation
 Looking from outside the mouth
 Roots up for maxilla, down for mandible
 Left or right from dental anatomy

19. QUESTIONS?

20. We need an xray source
 Dental xray machine
 Smaller focal spot so more detailed images than
standard machines
 More versatile as can adjust the angle of the head in
many directions (horizontal and vertical)
 Usually have fixed kV and mA so use the timer to
adjust exposure (may have preset times)
Courtesy Dr A Caiafa

21. We need an xray source
 Portable dental xray machines

22. We need an xray source
 Standard xray machine
 Settings for a 30-40 cm focal-film distance (FFD) are around 100 mA, time of
0.1or > sec.
 Range of KVp from 50 (cat or small dog) up to about 85 (large dog)
 Can use 100cm FFD and adjust using the inverse square law (double
distance = fourfold increase in time)

23. We need to capture and process the image
 Film processing facilities
 Wet chemicals in darkroom or chairside darkroom
 Rapid developer and fixer solutions - shortening the developing
time to 20 seconds (normally 4 minutes) and fixing time down to 2
minutes (normally 10 minutes)
 Automatic processors

24. Image capture and processing - digital
 DR and CR systems are available
 More expensive but eliminates need to process films in chemicals
 Can adjust images onscreen to optimise viewing
 Much easier to jump onto the steep part of the learning curve

25. Taking intraoral radiographs
What makes a diagnostic radiograph?
 Minimal distortion of length or aspect
 Adequate periapical tissue included
 No confounding superimposition

26. Taking intraoral radiographs
Parallel Technique
 Standard method used in veterinary
radiography where the film is placed
parallel to the object being radiographed
 This can only been used in the caudal
and mid mandible in dogs and cats (due
to the shape of the oral cavity)
 Lateral recumbency, side of interest
towards the xray machine

27. Taking intraoral radiographs
Bisecting Angle Technique
 Shoot perpendicular to the
bisecting angle (halfway between
the film plane and the long axis of
the tooth) to give an image that is
of a similar dimension to the object
 VERTICAL angulation

28. Taking intraoral radiographs
Bisecting Angle Technique
 If the beam is angled too vertically, perpendicular to film (ie too acute or
vertical), the image is foreshortened.

29. Taking intraoral radiographs
Bisecting Angle Technique
 If angle beam perpendicular to tooth (ie too flat or horizontal), the image
will be elongated.

30. Taking intraoral radiographs
 Problems with maxillary premolars and molars due to
superimposition of the zygomatic arch
 Come in more horizontally (~30o)
 Extraoral parallel or near-parallel view
 need to reverse the
orientation when
‘mounted’

31. Taking intraoral radiographs
 Differentiating the roots of the maxillary PM4s - the SLOB rule
 Lateral view has mesial (rostral) roots overlying each other
 Shift machine horizontally, about 30 degrees rostrally, and shoot
Palatal (lingual) root
rostrocaudally
Overlying roots Buccal root

32. PLAYTIME