Lecture 3 - Radiology

Question 1

Black X thru tooth?

Blue X thru tooth?

Answer 1

Congenitally missing

Previously extracted

Question 2

Existing

Composite?

Amalgam?

Gold?

Porcelain/Ceramic crown?

Answer 2

Outline surfaces in blue

Fill in surfaces in blue

Cross hatch surface in blue

Outline tooth in blue

Question 3

Red color means what?

Answer 3

Needs to be done

Question 4

Look at slide 5 and understand what is happening.

Answer 4

Do it

Question 5

What are 3 ways to maximize sharpness and resolution (image clarity)?

Answer 5

Use as small an effective focal spot as practical (Built into tube head)

Increase distance from focal spot to object with long open ended cylinder (aiming cylinder)

Minimize distance from object to image receptor (Film next to tooth)

Question 6

How is image size distortion minimized? 2 ways.

Answer 6

Increase focal spot to image receptor distance (aiming cone)

Decrease object to image receptor distance (film placement)

Question 7

How can image shape distortion be minimized? 2 ways.

Answer 7

Position image receptor (film) parallel to long axis of object (tooth)

Orient central ray (cone) perpendicular to the object and image receptor

*This can manifest as foreshortening or elongation of the film image

Question 8

What is foreshortening?

Answer 8

Central beam is perpendicular to the image receptor (film), BUT the object (tooth) is not

Question 9

What is elongation?

Answer 9

Central beam is perpendicular to the object (tooth), BUT not the image receptor (film)

Question 10

What is ideal?

Answer 10

Central ray should be perpendicular to the long axes of both the tooth and the image receptor

Question 11

What is the bisecting-angle technique?

Answer 11

Central beam should be directed at a right angle to the imaginary plane bisecting the angle formed by the image receptor (film) and the central axis of the object (tooth).

*Image is of correct length, but with distortions in tooth and height of alveolar crest

Question 12

What is the SLOB rule?

Answer 12

Same Lingual - Opposite Buccal

*Used for determining if an object found on a radiograph is located buccal, lingual, or in the same plane as the teeth

• Take normal radiograph, move x-ray head so its angled from the mesial and take it again
• If object moves mesial, or the same direction as you moved the tube head, then it is LINGUAL to the teeth
• If object moves opposite, distal, then it is located buccal to the teeth

Question 13

T/F - On a bitewing, you should see alveolar crestal bone.

Answer 13

TRUE

Question 14

Define radiolucent.

Answer 14

Any substance (part of the patient) that permits the transmission of xrays (less dense - appears dark on the radiograph)

Question 15

Define radiopaque.

Answer 15

Any substance (part of the patient) that blocks the transmission of xrays (more dense - more light)

Question 16

T/F - Enamel is radiopaque.

Answer 16

TRUE

Question 17

What is the lamina dura?

Answer 17

Tooth sockets are bound by a thick layer of dense bone - contiguous with cortical bone at the alveolar crest

Wider in teeth with heavy occlusion

Question 18

Maxillary molar PA

Answer 18

ALL molars, including 3rds

Distal 2nd premolar

Contacts open, proximal surfaces of molars

3-5 mm past apices, minimum

Question 19

Maxillary Premolar PA

Answer 19

Both premolars

Distal of canine

Medial of 1st molar

Contacts open, proximal surfaces of premolars

3-5 mm past apices, minimum

Question 20

Maxillary Canine PA

Answer 20

Canine and lateral incisor

Mesial of 1st premolar

Contact open b/t canine and lateral

3-5 mm past apices, minimum

Question 21

Maxillary Central Incisor PA

Answer 21

Central incisors - both

Mesials of lateral incisors

Contacts open b/t proximals of centrals

3-5 mm past apices, minimum

Question 22

Molar BWX Molars

Answer 22

All upper/lower

Distal of 2nd premolar

Molar contacts open

Crestal bone clearly visible

Question 23

Premolar BWX

Answer 23

Premolars - All upper/lower

Mesial of 1st molar

Distal of canines

Contacts open, proximal surfaces of premolars

Crestal bone clearly visible

Question 24

Mandibular Molar PA

Answer 24

All molars including 3rds

Distal 2nd premolar

Contacts open, proximal surfaces of molars

3-5 mm past apices, minimum

Question 25

Mandibular Premolar PA

Answer 25

Both premolars

Distal of canine

Mesial of 1st molar

Contacts open, proximal surface of premolars

3-5 mm past apices, minimum

Question 26

Mandibular Canine PA

Answer 26

Canine and lateral incisor

Mesial of 1st premolar

Contact open b/t canine and lateral

3-5 mm past apices, minimum

Question 27

Mandibular Central Incisor PA

Answer 27

Central incisors - both

Mesials of lateral incisors

Contacts open b/t proximals of centrals

3-5 mm past apices, minimum

Question 28

The alveolar crest is what?

Answer 28

Gingival margin of the alveolar process that extends b/t the teeth

RADIOPAQUE

*Normal when it is not more than 1.5mm apical to the CEJ

**May recede with age

Question 29

PDL - what is it?

Answer 29

CT that surrounds the root and connects it w/ the bone

Seen b/t the root and lamina dura extending from the alveolar crest around the root to the opposite alveolar crest

RADIOLUCENT

Question 30

What is cancellous/trabecular bone?

Answer 30

Lies b/t cortical plates

RADIOPAQUE plates and rods surrounding RADIOLUCENT marrow pockets

Question 31

What restorative materials are RADIOLUCENT?

Answer 31

Silicate cements - rare

Some composite resins

Porcelain

Question 32

What restorative materials are radiopaque?

Answer 32

Amalgam
Gold
Pins/posts
CaOH2
Gutta percha
Silver points
Some composites
Stainless steel crowns
Ortho appliances
Implants

Question 33

When can the nose be seen on a radiograph?

Answer 33

Max Ant PAs

Slightly radiopaque

Sometimes RADIOLUCENT nares are visible

Question 34

Where can you see the mental foramen on a radiograph?

Answer 34

Just apical to the 2nd premolar