Module 5

Question 1

Bitewings Advantages

Answer 1

• Simple and straightforward
• Difficult for tongue to displace the 
receptor
• Beam aiming device determines
angulation
• Cone cutting avoided
• Autoclavable/disposable holders

Question 2

Bitewings Disadvantages

Answer 2

• Not 100% reproducible
• Uncomfortable for patients
• Expensive holders
• Holders unsuitable for children

Question 3

Bitewings- Receptor positioned too far posterior

Answer 3

No premolars

Question 4

Bitewings - Receptor incorrectly placed

Answer 4

Displacement of receptor by tongue, Distortion

Question 5

Bitewings - ncorrect beam alignment in horizontal plane

Answer 5

• Too far posterior or anterior – coned off

* Not aimed through contact areas – overlapping

Question 6

Bitewings- Incorrect beam alignment in vertical plane

Answer 6

No superimposition of buccal and lingual cusps

Question 7

Bitewings - Incorrect exposure settings

Answer 7

Over exposed – burn out – poor contrast - dark image

• Underexposed – poor contrast – pale image

Question 8

Bitewings - movement of patient

Answer 8

Blurring

Question 9

Selection for Bitewings every 6 months

Answer 9

High risk

Question 10

Selection for Bitewings every 12 months

Answer 10

Moderate Risk

Question 11

Selection for Bitewings 12 -18 months primary / 2 years permanent dentition

Answer 11

Low Risk

Question 12

PA - Maxillary incisors and canines

Answer 12

• Accommodate height of palate

* Posterior position

Question 13

PA - Mandibular incisors and canines

Answer 13

• In floor of mouth

* In line with lower canines or premolars

Question 14

PA - Maxillary premolars and molars

Answer 14

• In midline

* Accommodate height

Question 15

PA- Mandibular premolars and molars

Answer 15

• Lingual sulcus

* Next to appropriate teeth

Question 16

PA Errors - Dentures and appliances not removed

Answer 16

Superimposed

Question 17

Pa Errors - Incorrect position of receptor

Answer 17

• Not over area of interest – no apicies or periapical tissues
• Bending - distortion

Question 18

PA Errors - Incorrect orientation

Answer 18

• no image (back to front)

Question 19

PA Errors- Poor alignment

Answer 19

• Horizontal – cone cutting, overlapping contact areas

* Vertical – cone cut, foreshortening, elongation

Question 20

Pa Errors - Poor communication

Answer 20

• movement, blurring

Question 21

PA Errors - Incorrect Settings

Answer 21

Poor contrast

Question 22

PA Errors - Double exposure

Answer 22

Receptor Used Twice

Question 23

Bisected Angle Technique

Advantages

Answer 23

• Comfortable positioning for patient
• Positioning is relatively simple and quick
• Dependant on correct angulation, image is same length as tooth
• Adequate for most diagnostic purposes

Question 24

Bisected Angle Technique

Disadvantages

Answer 24

Distortion due to many variables
• Elongation/ foreshortening – vertical angulation wrong
• Periodontal bone levels not seen
• Zygomatic shadow overlies roots of upper teeth
• Skill required for angulation assessment
• Not reproducible
• Cone cutting
• Roots and crowns overlap – horizontal angulation wrong
• Distortion of crowns common
• Foreshortened buccal roots of maxillary posterior
• teeth

Question 25

BA Errors - Elongation

Answer 25

Angulation too shallow, long image

Question 26

BA Errors - Foreshortening

Answer 26

Angulation too steep, short image

Question 27

BA Error - Coning

Answer 27

Angulation not central to film, partial exposure

Question 28

BA Error - Blurred image

Answer 28

Movement of patient or collimator

Question 29

BA Error - Transparent film

Answer 29

Film inserted the wrong way round

Question 30

BA Error - Fogged Film

Answer 30

Exposure to light before x-ray beam

Question 31

BA Error - Blank filme

Answer 31

Machine not switched on

Question 32

Upper standard occlusal

Answer 32

Standard occlusal

Question 33

Upper oblique occlusal

Answer 33

oblique occlusal

Question 34

true occlusal Mandibular

Answer 34

Lower 90° occlusal

Question 35

standard occlusal Madibular

Answer 35

Lower 45° occlusal

Question 36

Lower oblique occlusal madibular

Answer 36

oblique occlusal