Intraoral Radiography Techniques part 1

Question 1

Penumbra?

Answer 1

A penumbra is where you lose the sharpness of the edges due to divergence of the x ray beam

Question 2

Achieving best quality x ray image?

Answer 2

Aim for the penumbra to be as small as possible, with minimal magnification
Small focal spot
Long distance between focal spot and object
Short distance between object and image detector.

Question 3

Achieving Best Quality Intraoral Radiographs

Answer 3

Film and tooth as close together as possible
Film parallel to tooth
X-ray beam perpendicular to tooth and film
X-ray source to tooth distance as great as possible
Good size match between the xray beam and the image detector.

Question 4

Types of Intraoral Radiography:

Answer 4

Bitewings (BW)
Periapicals (PA/IOPA)
Occlusals

Question 5

What do Bitewing radiographs show?

Answer 5

Show the crowns of premolars and molars of both jaws
No or minimal overlap of enamel (i.e. no overlapping of teeth due to bad angle)
Should see from contact point between canine and first premolar to the most distal contact point
Horizontal (i.e. long axis of film horizontal) will also show superficial bone levels if bone loss < 6mm.

Question 6

What indications are visible on a bitewing radiograph?

Answer 6

• Caries
• Occlusal Caries
• Recurrent caries
• Depth of caries
• Caries progression
• Overhangs
• Calculus deposits
• Assessment of superficial bone levels / architecture
• Pins / perforations

Question 7

Technique for BW

Answer 7

Use film holder with beam aligning devices

Question 8

Film sizes for adults and children BW

Answer 8

Size 2 for adults

Size 0 or 1 for children

Question 9

Vertical BW

Answer 9

Film is portrait – for a longitudinal view showing fewer teeth but more bone area
Usually need at least 2 each side to cover the posterior teeth.

Question 10

Adv of Film holders for a BW

Answer 10

• Simple
• Film is not displaced by the tongue
• Beam always at right angles to film
• Less chance of cone cutting
• Reproducible technique

Question 11

Disadvantages of film holders for BW

Answer 11

• More expensive initially - eqpt purchasing and sterilization.
• May be uncomfortable- bulky.

Question 12

Adhesive tab BW technique

Answer 12

OG technique not used as much now but can be used for children that can’t handle the larger film holders

Question 13

Advantages of the adhesive tab BW method:

Answer 13

Cheap
Simple
Good for small children

Question 14

Disadvantages of the adhesive tab BW method

Answer 14

Not reproducible
More change of coning off
Operator dependent

Question 15

Periapical radiograph- what should you see?

Answer 15

All of tooth (crown and root)
Periapical tissues (approximately 3 mm beyond  the apex)

Question 16

Reasons for taking the PA radiography

Answer 16

Apical pathology
– e.g. rarefying osteitis, cysts, root resorption
Periodontal disease
Endodontics
Root morphology prior to extraction
Impacted teeth
Implant assessment
Trauma