ARH Dental Radiology Workshop

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  • 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.
  • ARH Dental Radiology Workshop

    1. 1. Dental Radiology Workshop Dr Christine Hawke Veterinary Dental Consultant29th April 2012
    2. 2. Would you do orthopaedics without rads? At least 2/3 of each tooth is below the gumline and not visible without radiographs!
    3. 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. 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. 5. Lamina lucida (PDL)Alveolar bone Lamina Dura (Crestal bone) Pulp Cementum Enamel Dentine
    6. 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. 7. Assessing periodontal disease Looks can be deceiving……. http://www.avds-online.org
    8. 8. Dental extraction planning
    9. 9. Tooth resorptionVery common in cats, and very painful Radiographs are critical for assessment andtreatment planning Retained roots Resorbing roots
    10. 10. Missing teeth
    11. 11. Missing teeth
    12. 12. Fractured teeth
    13. 13. Discoloured teeth
    14. 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. 15. Periapical lucencies - normal or not?  Compare with contralateral side
    16. 16. Worn teeth
    17. 17. Oral tumours and swellings Courtesy Dr A Caiafa
    18. 18. Interpreting dental radiographs  Orientation  Looking from outside the mouth  Roots up for maxilla, down for mandible  Left or right from dental anatomy
    19. 19. QUESTIONS?
    20. 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. 21. We need an xray source Portable dental xray machines
    22. 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. 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. 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. 25. Taking intraoral radiographs What makes a diagnostic radiograph?  Minimal distortion of length or aspect  Adequate periapical tissue included  No confounding superimposition
    26. 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. 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. 28. Taking intraoral radiographsBisecting Angle Technique If the beam is angled too vertically, perpendicular to film (ie too acute or vertical), the image is foreshortened.
    29. 29. Taking intraoral radiographs Bisecting Angle Technique  If angle beam perpendicular to tooth (ie too flat or horizontal), the image will be elongated.
    30. 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. 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. 32. PLAYTIME

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