Intro to Radiology and Radiographic anatomy

Question 1

Define radiography

Answer 1

Techniques involved in producing radiographic images

Question 2

Define radiology

Answer 2

Interpretation of medical imaging

Question 3

Define radiation protection

Answer 3

Protection of patients and staff from hateful effects of ionising radiation

Question 4

What is a radiograph?

Answer 4

• An image produced by transmission of X-rays through an object
• X-rays pass through the body to reach the image detector and cause blackening in the image
• Image created by different absorption of X-ray photons by different tissues o Two-dimensional image of a 3D object.

Question 5

5 Features of X-rays

Answer 5

• High energy electromagnetic radiation
• Travel as wave packets called ‘photons’ o Invisible
• Attenuated by matter - Rays are either absorbed or scattered
• Ionizing radiation which can damage tissue - all radiographs must be “justified” i.e. the potential benefit must outweigh the risk.

Question 6

Features of radio opaque areas in a radio graphic image?

Answer 6

White - rep dense structures w have attenuated the X-ray beam

Question 7

Features of radiolucent areas in radiographic image

Answer 7

-black
-area where X-ray beam has passed thru object

Question 8

What do the Grey shadows represent ?

Answer 8

X-ray beam stops to varying degreee

Question 9

Density of radiographic appearance effected by:

Answer 9

Density affected by:
Type of material
Thickness of material
Shape of the object
Intensity of the X-ray beam
Position of object relative to the X-ray beam and receptor
Sensitivity and type of the image receptor.

Question 10

Limitations of viewing a 2D image of a 3D object

Answer 10

o 1 view only o Superimposition
• Overlapping shadows of different parts of an object or a separate object
• Causes limitation of information on location and shape of the object.
• E.g. Braces - stops looking at crowns of teeth (caries is radiolucent)
o No Depth information

Question 11

What is the image orientation of X-rays

Answer 11

• AlI X-rays are orientated the same
o Patients Left is on your Right, Patient’s Rights is on your Left
• Right bitewing:
• Molars = Left
•Premolars = Right
• Left bitewing:
• Molars = Right
• Premolars = Left

Question 12

What does the dental anatomy look like on a radiographic image

Answer 12

Enamel - Very dense tissue - white
Dentine- less dense than enamel
Root Canal - soft tissue - radiolucent
PDL - Black lines (very easily penetrable)
White line - edge of bone (cortical bone - lamina dura)

Question 13

Types of radiographs

Answer 13

Intraoral and extraoral

Question 14

Where is image detector placed in intraoral radiograph

Answer 14

Image detector is placed inside patient mouth
Upper Occlusal - 65-degree angle; localisation to see on palatal or labial side of incisor teeth
Lower Occlusal - at a near 90 degree angle; localisation to see on lingual or buccal side of incisor teeth (In picture you can see a sublingual duct has a stone blocking it, something not visible on a panoramic view).

Question 15

What do incisors look like on radiograph

Answer 15

Enamel thinner on incisor than molar cos less density
Incisors single root

Question 16

Where is image detector placed in extraoral radiograph

Answer 16

outside patients mouth

Question 17

What does dental pantomogram (DPT) show

Answer 17

Shows full dentition of the maxilla and mandible -allows to see present teeth and unerupted teeth in jaw - can be useful if patient has large bone lesion.

Question 18

What is a panoramic

Answer 18

Full view of teeth
Patients left is on right of screen and vice versa

Question 19

What is lateral cephalogram

Answer 19

Often used in orthodontics
Determine the relationship of mandible, maxilla and skull base
Can see angulation and development of skull Often used in orthodontics

Question 20

How is the palmer notation charted?

Answer 20

Mouth divided into 4 quadrants
Teeth number 1-8 from central incisor
Letters and numbers system:
• Modification of Palmer
• LR3 to represent lower R canine
Should start from Upper R -> Upper [-> lower [ -> lower R

Question 21

What does incisive foremen look like

Answer 21

Inside patient mouth
Is the opening of the incisive canal which contains; the spheno-palatine artery and palatine nerve.
Radiolucent (dark area on radiograph)
due to it being a foramen; less bone, less dense > fewer x-rays are attenuated

Question 22

What does the canine fossa look like

Answer 22

Where bone of maxilla is thinner, mesial to canine root
Bony depression
Radiolucent area due to thinner bone to attenuate x-ray beam

Question 23

What does floor of nasal cavity look like?

Answer 23

Anterior teeth can be seen (crowns not localised)
Can see lateral incisor and some of first premolar
tooth
Can see a radiopaque white line (covered in red)
which is the floor of the nasal cavity

Question 24

Y-shape of Ennis

Answer 24

Upside down Y of cortical bone
Where the floor of the nasal cavity meets the floor of the maxillary antrum
Bony margin at the edge of the two cavities

Question 25

Floor of Maxillary antrum

Answer 25

periapical radgiorpah upper right lateral in cisor to 2nd molar can see partial Y of ennis Floor of maxillary antrum - radiopaque - white, scallops around maxillary teeth - should be intact and antrum floor Sinus septum - normal bony projection

Question 26

Soft tissue shadow of the cheek-nasolabial fold

Answer 26

• Periapical of the UL quadrant • Cheek-Nasolabial fold - shows where the cheek is fuller =more radiopaque area due to greater attenuation

Question 27

Soft tissue-nose

Answer 27

Nose can be seen especially at a high angled periapical radiograph Nose = white shadow and radiopaque area over the apices of the central incisors. In midline of maxillary you can see intermaxillary suture - neonatal line.

Question 28

Zygomata

Answer 28

White shadow at the posterior maxillary molar regions

Question 29

Zygomatic buttress

Answer 29

Where zygoma contact maxilla Radiopaque block of bone - zygoma

Question 30

Pterygoid hamulus

Answer 30

Back of alveolar process at the end = maxillary tuberosity Just posterior to the maxillary tuberosity= pterygoid hamulus

Question 31

Coronoid process

Answer 31

Posterior maxillary region of the UR quadrant view. Can see a bony finger - coronoid process of mandible.

Question 32

Submandibular fossa and mylohyoid ridge

Answer 32

Cross section of left body of mandible On the lingual surfaces ridge where the bone is thicker, mylohyoid ridge. Mylohyoid ridge is where the mylohyoid muscle attaches to the mandible Inferior to mylohyoid ridge = submandibular fossa - where the submandibular gland sits.

Question 33

Inferior alveolar canal

Answer 33

Running through centre inf. Alveolar canal - sensitivity to teeth in mandible - radiopaque lines = cortical margins or canal.

Question 34

Mental foramen

Answer 34

where the Inferior alveolar canal exits the mandible Radiolucent area Between the 15 and 2nd premolars in mandible

Question 35

Lingual Forman

Answer 35

Small foramen on lingual surface of mandible Projects inferior to the central incisors Small radiolucent area - should have a good corticated margin on the outside

Question 36

Maxillary antrum

Answer 36

Should always see 4 white corticated lines: Antral floor, har palate, zygomatic buttress, posterior of antrum

Question 37

Soft tissue shadows

Answer 37

Should see 4 structures: Pinna of ear (both sides), dorsum of tongue (usually tell patients to put to roof of mouth), soft palate and epiglottis

Question 38

Direct restoration

Answer 38

Generally, radiopaque

Question 39

Root canal treatment

Answer 39

Nerve and blood vessel is taken out and filled with restorative material - canal is now filled and appears more radiopaque

Question 40

Crown

Answer 40

• Full coverage of restorative material • Some can be entirely metal, or porcelain with a metal core (which appears radiopaque)