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
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
9. Tooth resorption
Very common in cats, and very painful
Radiographs are critical for assessment and
treatment planning
Retained roots
Resorbing roots
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
18. Interpreting dental radiographs
Orientation
Looking from outside the mouth
Roots up for maxilla, down for mandible
Left or right from dental anatomy
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
In a report* intraoral radiographs: revealed clinically significant pathology in 27.8% of dogs & 41.7% cats (no abnormal findings on oral exam) revealed more pathology in 50% of dogs & 53.9% of cats (with abnormal findings on oral exam) * Verstraete et al. Am J Vet Res 1998 59: 692-5
In a report* intraoral radiographs: revealed clinically significant pathology in 27.8% of dogs & 41.7% cats (no abnormal findings on oral exam) revealed more pathology in 50% of dogs & 53.9% of cats (with abnormal findings on oral exam) * Verstraete et al. Am J Vet Res 1998 59: 692-5
In a report* intraoral radiographs: revealed clinically significant pathology in 27.8% of dogs & 41.7% cats (no abnormal findings on oral exam) revealed more pathology in 50% of dogs & 53.9% of cats (with abnormal findings on oral exam) * Verstraete et al. Am J Vet Res 1998 59: 692-5
In a report* intraoral radiographs: revealed clinically significant pathology in 27.8% of dogs & 41.7% cats (no abnormal findings on oral exam) revealed more pathology in 50% of dogs & 53.9% of cats (with abnormal findings on oral exam) * Verstraete et al. Am J Vet Res 1998 59: 692-5
In a report* intraoral radiographs: revealed clinically significant pathology in 27.8% of dogs & 41.7% cats (no abnormal findings on oral exam) revealed more pathology in 50% of dogs & 53.9% of cats (with abnormal findings on oral exam) * Verstraete et al. Am J Vet Res 1998 59: 692-5
In a report* intraoral radiographs: revealed clinically significant pathology in 27.8% of dogs & 41.7% cats (no abnormal findings on oral exam) revealed more pathology in 50% of dogs & 53.9% of cats (with abnormal findings on oral exam) * Verstraete et al. Am J Vet Res 1998 59: 692-5
In a report* intraoral radiographs: revealed clinically significant pathology in 27.8% of dogs & 41.7% cats (no abnormal findings on oral exam) revealed more pathology in 50% of dogs & 53.9% of cats (with abnormal findings on oral exam) * Verstraete et al. Am J Vet Res 1998 59: 692-5
The posterior mental foramen is located ventral to the mandibular third premolar. At times it can be confused with a periapical lesion. If in doubt, radiogrpah the tooth at angle, which will show the foramen is not connected to the tooth's apex.
In a report* intraoral radiographs: revealed clinically significant pathology in 27.8% of dogs & 41.7% cats (no abnormal findings on oral exam) revealed more pathology in 50% of dogs & 53.9% of cats (with abnormal findings on oral exam) * Verstraete et al. Am J Vet Res 1998 59: 692-5
Proper light and magnification Need to orientate the radiograph first. When shooting, you must face the dot towards the xray machine (due to lead shield in packet). If shooting intraoral, this means that if you orient it this way when reading (bubble up) you will be looking from the outside of the mouth (as xray machine shoots from out to in).Can the orient so mandibular roots go down and maxillary roots go up. Can then decide mesial and distal from dental anatomy, can then tell if left or right jaw. For extraoral views eg maxillary caudal teeth in cat) place embossed dot down when viewing (as shooting from in to out).
Parallel technique Can only really be used for the mandibular premolars and molars, and even this is hard rostrally due to mandibular symphysis and frenulum of the tongue Hard to get it truly parallel but distortion minimized if less than 20 degree deviation Lateral recumbency with side you want uppermost towards the xray machine Film between tongue and teeth, not bent and as close to teeth as possible If object-to-film distance (OFD) is increased, then magnification and distortion occur. Increasing the focal-film distance (FFD) (long cone technique) can dramatically reduce distortion, but higher exposure required.
