Interpreting and reporting radiographs

Question 1

When is a bitewing used

Answer 1

• caries detection because good view of crown

- NOT for PA pathology because apices aren’t shown

Question 2

When is a periapical used

Answer 2

To see whole tooth and surrounding structures

Question 3

When is an occlusal used

Answer 3

• for fractures
• localisation of teeth
• salivary calculous

Question 4

When is a panoramic used

Answer 4

• NOT for caries
• shows unerrupted teeth
• recommended for perio but there isn’t as much detail as a PA

Question 5

What are the three viewing conditions required for analysing radiographs

Answer 5

1. even uniform bright light
2. dark room
3. quiet room

Question 6

What questions should be asked when analysing the technique used

Answer 6

1. distortion? = forshadowing/elongation?
2. rotation? asymetry?
3. how is the reolution sharpness and contrast?
4. fogged film? artefactual shadows?
5. dark + overexposed? light + underexposed?

Question 7

How is the lamina dura seen in radiographs

Answer 7

• thin radiopaque layer of dense cortical bone surrounding tooth
• thicker than trabecular bone

Question 8

How is the alveolar crest seen in radiographs

Answer 8

• it is the gingival margin of alveolar process extending between the teeth
• radiopaque line
• not more than 1.5mm from CEJ of adjacent teeth

Question 9

How is the periodontal ligament space seen in radiographs

Answer 9

radiolucent area

• space between the roots and lamina dura
• composed of collagen

Question 10

How is the cancellous bone seen in radiographs

Answer 10

thin radiopaque plates + rods

• trabecular/ spongeosa bone lying between cortical plates in both jaws
• surrounds radiolucent marrow spaces
• anteriorly larger in the maxilla than posteriorly
• marrow space is larger posteriorly (radiolucent)

Question 11

How is the intermaxillary medial suture seen in radiographs

Answer 11

thin radiolucent line extending from angle of crest between central incisors

Question 12

How is the anterior nasal spine seen in radiographs

Answer 12

protrusion of maxilla at base of nose (most anterior part of the maxilla) shows as radiopaque

Question 13

How is the incisive foramen seen in radiographs

Answer 13

oral opening of nasal palatine canal thus appears radiolucent between the central incisors

• cysts can develop here

Question 14

How is the superior foramina of nasal palatine canal seen in radiographs

Answer 14

two small radiolucent areas above apices of central incisors

Question 15

How is the lateral incisive fossa seen in radiographs

Answer 15

depression in maxilla near apex of lateral incisor which shows as radiolucent in IOPAs

Question 16

How is the nasolacrimal canal seen in radiographs

Answer 16

indent in inferior nasal conche, maxilla and lacrimal bone

Question 17

How is nose soft tissue seen in radiographs

Answer 17

it is superimposed over roots of teeth

Question 18

How are the maxillary sinuses seen in radiographs

Answer 18

these are air containing cavities lined by mucous membranes extending from the distal aspect of canines and post. maxilla wall of tuberosity

• IOPAs show a thin radiopaque line

Question 19

What is numetisation of the maxillary sinus

Answer 19

extention of the sinus wall to surrounding bone where teeth are thus causing premature erruption

Question 20

How is the zygomatic process seen in radiographs

Answer 20

as an extension of lateral maxillary surface in region of 1/2 molar apicies; this is the articulation for zygomatic bone and appears as a radiopaque U-shaped line

Question 21

How is the zygomatic bone seen in radiographs

Answer 21

cheek prominance, triangular, dense, radiopaque

Question 22

How are the pterygoid plates seen in radiographs

Answer 22

Next to hamular process; post. to tuberosity of maxilla; single radiopaque shadow

Question 23

How is the maxillary tuberosity seen in radiographs

Answer 23

Rounded eminence at posterior aspects of maxilla

Question 24

How is the lingual foramen seen in radiographs

Answer 24

radiolucent hole in centre of genial tubercules

- the lingual nutrient vessel passes through here

Question 25

How are the genial tubercules seen in radiographs

Answer 25

radiopaque circles surrounding lingual foramen below apices of the incisors

Question 26

How is the marginal ridge seen in radiographs

Answer 26

a thick radiopaque line bilaterally; ant. to mandible

Question 27

How is the mental foramen seen in radiographs

Answer 27

radiolucent area between apices of premolars

Question 28

How is the external oblique ridge seen in radiographs

Answer 28

runs parallel to the mylohoid ridge but higher up

Question 29

How is the internal oblique ridge seen in radiographs

Answer 29

Stops at 3rd molar and is continuous with the mylohoid line; lingual surface of mandible extends to the premolar area

Question 30

How is the mandibular canal seen in radiographs

Answer 30

Arises at mandibular foramen on lingual side of ramus; contains inferior alveolar nerve and vessels

Question 31

What are the 5 progressions in how caries is seen on radiographs

Answer 31

R0 = no caries
R1 = inseeping caries
R2 = moderate caries into the inner enamel 
R3 = advanced caries into outer dentine 
R4 = severe caries into inner dentine (1/2 through pulp)

• Radiographs always underestimate real caries lesions

Question 32

What is cervical burnout

Answer 32

An artefact where medial and distal borders are ill defined in the cervical region; there is radiolucency above the alveolar crest which mimics the appearance of root caries

Question 33

Why is it important to identify cervical burnout in radiographs

Answer 33

Because it mimics root caries and so there is a chance of a false positive diagnosis of this; the match band illusion at the DEJ also appears as root fracture

Question 34

Where and when is a radicular cyst formed

Answer 34

At the apex of affected teeth

As a result of pulp necrosis