Dental Radiographs

Question 1

Name the abnormality that is shown in the tooth below:

Answer 1

Supernumerary root of the mandibular 4th premolar

Question 2

Compare and contrast when the parallel and bisecting angle techniques of teeth radiography should be used:

Answer 2

• Parallel technique - useful for mandibular molars and premolars
• Bisecting angle technique - all teeth in the mouth

Question 3

Describe the principle of a parallel X-ray technique:

Answer 3

Question 4

Describe how the bisecting angle technique is performed:

Answer 4

• Used where the film cannot be placed parallel to the long axis of the tooth
• Shoot perpendicular to the bisecting angle

Question 5

What are the standard radiographic projections?

Answer 5

• Rostral maxillary
• Rostral mandibular
• Right & left maxillary: may need one cranial and one caudal
• Right & left mandibular: may need one cranial and one caudal

Question 6

Describe how you would take the 6 radiographic projections?

Answer 6

1. Right maxilla: Animal in VR - 45 degree bisecting from the right side
2. Maxillary incisors: Animal is in VR - 55 degree angle from dorso-ventral angle
3. Left maxilla: Animal in VR - 45 degree bisecting angle from the left hand side
4. Left mandible: Animal in DR - 45 degree bisecting angle from left hand side
5. Mandibular incisors: Animal in DR - 55 degree from horizontal
6. Right mandible: Animal in DR - 45 degree angle from the horizontal

Question 7

Name the process that is shown in the image below:

Answer 7

Palatine processes of the maxilla

Question 8

Name the structures that are shown in the mandible below:

Answer 8

1. Mandibular canal
2. Mental foramina

Question 9

Name the radiographic feature that is shown below:

Answer 9

1. Middle mental foramina

Question 10

Name the radiographic feature that is shown in the X-ray below:

Answer 10

Chevron - normal radiolucency @ the base apex - non-diseased tooth (common in maxillary incisors, maxillary canines and mandibular molar 1)

Question 11

Name the features that are shown in the radiograph below:

Answer 11

1. Chevron - normal radiolucency apically on the tooth
2. Cervical burn out - @ neck of tooth - more radiolucent due to thinning of the enamel just above the start of alveolar bone

Question 12

Name the structure that is shown in the image below:

Answer 12

Mandibular canal

Question 13

Name the structures that are shown in the diagram below:

Answer 13

1. Palatine fissure
2. Incisive canal
3. Chevron

Question 14

Describe the appearance of deciduous teeth:

Answer 14

• Relatively smaller
• Less radio-dense than permanent

Question 15

Describe the structure of the normal young adult tooth:

Answer 15

• Dentine is thin → secondary dentine is laid down as animal ages
• Pulp chamber is large
• Initially the root apex is open → as animal ages will close in 9-12 months
• Lamina dura is quite distinct

Question 16

Compare the canines in the cat to the dog:

Answer 16

Canine is much straighter in a dog compared to a cat

Question 17

Describe the four normal features of periodontal anatomy that should be seen in the teeth:

Answer 17

1. Crestal bone - should be close to CEJ (approximately 2mm apically) - normally a pointed angle
2. Lamina dura - dense lining of alveolus - seen as a white line
3. Periodontal ligament - appears as a black line
4. Furcation - present right into furcation

Question 18

What are the four stages of alveolar bone loss and what would you expect to see with each in terms of bone loss?

Answer 18

• 1: Gingivitis, no attachment loss
• 2: Mild <25% alveolar bone loss
• 3: Moderate 25-50% alv bone loss
• 4: Severe > 50% alv bone loss

Question 19

How much bone loss must occur for radiographic signs of periodontal disease to become apparent?

Answer 19

40% of the bone must be lost for it to be visualised on Xray

Question 20

Name the two features that comprise attachment loss:

Answer 20

1. Attachment loss
2. Gingival recession
3. Periodontal pocket

Attachment loss = gingival recession + periodontal pocket depth in mm

Question 21

Describe the features that you would expect too see in Stage 0 Periodontal disease:

Answer 21

1. Clean crowns
2. Tartar is starting to develop
3. Gum margins are flat and pink → creates a scalloped edge against teeth
4. Bone levels are just under the bulge of crown (NO BONE LOSS)

Question 22

What are the clinical signs seen in Stage 1 periodontal disease?

Answer 22

• Build up of tartar and slightly reddened/swollen gums (NO BONE LOSS)

Question 23

What is seen radiographically in Stage 2 periodontal disease?

Answer 23

0 - 25% bone loss - fuzzy where it should be sharp

Question 24

What is seen in Stage 3 periodontal disease?

Answer 24

25-50% bone loss has occurred

Question 25

What percentage of bone loss is seen in Stage 4 periodontal disease?

Answer 25

Greater than 50% bone loss

Question 26

What is typically observed in periodontitis?

Answer 26

Horizontal and vertical bone loss

Question 27

What are the radiographic signs of endodontic disease that may be seen?

Answer 27

* Disrupted crown * Widening of endodontic canal * Internal reabsorption * Periapical lucency - bulbous w/lack of lamina dura

Question 28

Name the radiographic abnormality shown in the image below?

Answer 28

1. Periapical lucency

Question 29

Name the type of tooth resorption that is shown in the image below:

Answer 29

Type 1 tooth resorption

Question 30

Name the type of tooth resorption that is shown below:

Answer 30

Type 2 tooth resorption

Question 31

Name the type of tooth resorption that is shown below:

Answer 31

Type 3 tooth resorption

Question 32

Name the condition that is shown in the radiograph below:

Answer 32

* Hypercementosis - thickened cementum (often apical 3rd - makes extraction more difficult)

Question 33

What are the four main types of cysts that can occur in teeth?

Answer 33

1. Dentigerous cyst - unerupted tooth especially mandibular premolar 1 (Boxers) 2. Radicular cyst - from endodontic disease 3. Primordial cyst - degeneration of tooth bud 4. Odontogenic tumours

Question 34

Name the most likely type of tumour shown in the radiograph below:

Answer 34

Peripheral Odontogenic Fibroma - ossifying type (no invasion of bone)

Question 35

Name the most likely type of tumour demonstrated in the radiograph below:

Answer 35

Ancathomatous ameloblastoma - local invasion of the mandible - slow growth resulted in teeth being pushed apart

Question 36

Name the most likely neoplasm in the mouth of the dog shown below:

Answer 36

SCC -→ leading to destruction of the mandible