RADIOGRAPHY Veterinary dental nursing procedures RADIOGRAPHY

RADIOGRAPHY

Veterinary dental nursing procedures

RADIOGRAPHY

5888H - Veterinary Dental Nursing

RADIOGRAPHY

Radiology vs Radiography

• Radiography– taking and processing pictures

• Radiology– interpreting pictures


RADIOGRAPHY

Purpose

• Diagnosis

• Planning

• Post-treatment

• Prognosis


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Radiographs to diagnose

• Congenital e.g:– Malformations

• Acquired e.g:– Periodontal disease– Fractured teeth– Discoloured teeth– “Neck lesions”– Jaw lesions


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Planning

• Extractions– Root infections– Impacted teeth– Root fusion (ankylosis)– Feline “neck lesions”

• Endodontics– Root canal treatment

• XR v impt for measuring length of drills


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Monitoring

• Lesion progression

• Post op– Assess treatment success


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Film Types

• Screen Film– Intensifying screens within cassettes permit

shorter exposure times– But cassettes don’t fit into mouth

• Non-Screen Film– Normal

• Slow & longer exposure but good detail• Small & flexible

– Dental• Small pre-cut sizes• Has 2 sides:

– One incorporates foil/lead backing – Other with a raised dot – point to the beam


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Dental Film


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Film positioning

• Extraoral

• Intraoral


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Film positioning

• Intraoral– Less superimposition of teeth– Better detail

• Film closer to tooth• Less scattered radiation

– Usually need dental film


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Patient positioning

• Mandible- animal in dorsal recumbency

• Maxilla- animal in ventral recumbency


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Full mouth views

• Would require 6-8 views to evaluate all 4 quadrants


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Patient positioning

• Motionless– Heavy sedation– General anaesthesia

• Positioning aids– Sandbags, lead sleeves– Troughs, Foam wedges, Syringe cases– Tape– Cardboard or spring loaded devices


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X-Ray Machines

• Normal

• Dental – Smaller – More manoeuvrable– Safer – Better images


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X-Ray Machines

• General Purpose– Large and difficult to manipulate

• Ideally would want to get to within 15 cm

• Dental– Easy to manipulate close in– Safer (less scatter)– Wall or castor mounted– Simple to operate

• fixed kV and mA • Adjust time


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Dental X-Ray Machines


RADIOGRAPHY

Developing

• Manual– Mini dark room boxes available

• Automatic– Needs to be able to handle small dental

film

• Within film envelope– Special dental films


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Accessories

• Film positioners

• Bite blocks (props)

• Film viewer with magnifier

• Film marker

• Film storage envelopes


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Accessories

Film Viewer

Film Positioners


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How many views?

• At least 2 views at right angles– Plus extra obliques to highlight specific

problems


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Tooth image distortion

• Size accuracy & fine detail more important than for normal radiographs– Require exact measurements in

endodontics- measuring exact length of root canal

– Small & subtle lesions may need to be detected


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Types of distortion

• Anatomic– When film cannot be positioned parallel to

object being measured (tooth)

• Beam magnification– Point source effect

• Blurring– Movement – Aperture effect– Scatter


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Anatomic distortion

• Shortening

• Lengthening


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Beam magnification

• Point source effect


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Blurring distortion

• Movement

• Aperture effect (depth of field)

• Scatter (thickness of tissue)


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Reducing distortion

• Centering • Coning down (collimation)• Longer anode-film distance

– Reduces point source effect

• If possible– Film parallel to length of tooth

• Otherwise– Bisecting angle technique


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Radiographic Beam Direction

• 90° Angle (Parallel) Beam technique– Film & Tooth parallel (< 15° separation)

• Possible for lower PM2-3 M1-3 (film inside mouth)• Possible for lower PM1 and all Ms (film outside)

– Beam perpendicular

• Bisecting Angle Beam technique– Film & Tooth not parallel (>15° separation)

• Required for all Incisors and Cuspids (Canines)

– Beam angle is simply averaged to compensate


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Parallel technique


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Parallel technique


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Mandibular molars

• Can position film parallel

• Place lingual side

• Perpendicular beam


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Parallel technique


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Bisecting Angle


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Bisecting angle technique

1. Get Long Axis of tooth

2. Get Long Axis of film

3. Bisecting Axis = half way between 1 and 2

4. Aim beam perpendicular to Bisecting Axis


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Bisecting angle technique

• Use a straight object (e.g. tongue depressor) to help imagine bisecting angle


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Mandibular Canine

1. Film2. Tooth

3. Bisecting Angle

X-RA

Y BE

AM


RADIOGRAPHY

The imaginary bisecting line

• Is simply ‘eyeballed’


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Mandibular Canine


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Rostral mandibular PMs

• Symphysis prevents placing film parallel

• Bisecting angle


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Maxillary Canine - lateral


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Maxillary Canine – lat. oblique


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Maxillary Canine – lat. oblique


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Carnassial


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A Near-Parallel technique


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A Near-Parallel technique


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Ventro-dorsal technique – skull


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Dorso-ventral technique – skull


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45° Lateral Oblique technique

Mandible


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45° Lateral Oblique technique

Maxilla


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Mandibular incisors/canines

• Dorsal recumbency

• Bisecting angle

• Center on1st Incisors


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Any problems?

• No - normal


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Any problems?

• Periodontal disease


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Any problems?

• Apical lysis (probably apical abscess)


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Any problems?

• Tooth hardening (sclerosis) after pulpitis


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Any problems?

• ‘Root canal’ has been performed


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X-Ray Safety

• Usual precautions

• Remember: – 1 brick = 0.5 mm lead


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Digital Imaging

• Still uses X-Rays

• Uses a small X-Ray sensor

• Immediate image obtained– Can easily manipulate

image• Enlarge• Contrast • Store & Share


RADIOGRAPHY

The End

Documents

RADIOGRAPHY Veterinary dental nursing procedures RADIOGRAPHY