RADIOLOGY Flashcards
The most commonly impacted tooth is:
(A) Mandibular third molars
(B) Maxillary third molars
(C) Maxillary canines
(D) Mandibular premolars
(A)
Briefly explain the five categories for Winter’s classification of third molars
- Vertical
- Horizontal
- Mesioangular
- Distoangular
- Inverted or transverse
(refer to lecture slides for images)
A patient presents to your clinic with an erupting 48. On radiographic examination you note - the highest portion of the molar is below the CEJ of the 47 and less than half of the crown is within the ramus. The classification of this molar based on Pell and Gregory is:
(A) A, Class I
(B) C, Class II
(C) B, Class III
(D) A, Class II
(B)
Name 5 signs of mandibular third molar in close proximity to inferior alveolar canal
Darkening of root
Deflected roots
Narrowing of root
Dark bifid of root apex
Diversion of mandibular canal
Interruption of radiopaque borders of mandibular canal
Narrowing of mandibular canal
Which of the following is a disadvantage of MRI?
(A) Uses ionising radiation
(B) Metal distorts image
(C) Invasive
(D) Low quality images of soft tissue
(B)
Which of the following is NOT an advantage of diagnostic ultrasound imaging?
(A) Inexpensive
(B) Non ionising radiation
(C) High resolution images of deep structures
(D) Real time images
(C) It has poor image resolution of deep anatomical structures
On OPG imaging, you notice a lobulated, cauliflower radiopacity around the submandibular region. The patient is asymptomatic. Which of the following is the most likely diagnosis?
(A) Tonsolith
(B) Lymph node calcification
(D) Sialolith
(C) Cyst/Polyp
(B)
Tonsolith is classified as a
(A) Idiopathic calcification
(B) Dystrophic calcification
(C) Metastatic calcification
(D) Heterotropic ossification
(B) Normal calcium deposition at chronically inflammed site
Ossification of interstitial tissue of muscle and associated ligaments is:
(A) Osteoma cutis
(B) Arteriosclerosis
(C) Fibrous hyperplasia
(D) Myositis ossificans
D)
You take a pA of 36 and 37 for a patient and note an ill-defined mixed density lesion of the surrounding bone and hypercementosis of the roots. After taking an OPG, you note that the IAN is displaced superiorly. Intraorally, you note a slight swelling around the external oblique ridge but the patient reports nil symptom. Which pathology is this most likely and what is your ddx?
Fibrous dysplasia - IAN being displaced superiorly is characteristic in this pathology.
Ddx:
• Brown tumour of hyperparathyroidism
• Paget’s Disease
• Periapical osseous dysplasia (late stage)
• Healing/healed simple bone cyst
• Osteomyelitis
What are your ddx for periapical osseous dysplasia?
Early → Chronic apical periodontitis
Mixed/mature phase
- Cementblastoma
- Enostosis
- Complex odontoma
Briefly describe the following for anuerysmal bone cyst
1. Shape
2. Site
3. Size
4. Internal structure
5. Periphery
6. Effects on surrounding structure
7. List 3 ddx
• 1. Shape: Circular
• 2. Site: mandible > maxilla, molar/premolar region
• 3. Size: Varies
• 4. Internal structure:
o Small lesion radiolucent
o Multilocular appearance, presence of septa and ill-defined granula wispy sept at right agnles to periphery
• 5. Periphery: Well-defined, non corticated
• 6. Effects on surrounding structures:
o Displace and resorb teeth
o Extreme expansion of cortices
- Ddx:
- Central giant cell granuloma
- Ameloblastoma
- Cherubism
List the categories for soft tissue calcifications
- Heterotrophic calcifications = Disorganised
- Dystrophic = Inflammed sites - lymph nodes, cysts and polyps, fibrous hyperplasia, tonsoliths, arteriosclerosis, calcified atherosclerotic plaque
- Idiopathic = Noninflammed sites - thyroid and triticeous cartilage, sialolith, rhinolith/antrolith, phebolith - Heterotrophic ossifications = Organised
- Styloid
- Myositis ossificans
- Osteoma cutis
Explain what types of imaging should be used for detecting soft tissue and hard tissue abnormality of TMJ.
Soft tissue
- CT and MRI only in complex cases where home management did not work
- MRI = Excellent for detecting disc displacement and joint effusion
Hard tissue
- CT = Gold standard for degenerative joint disorders and hard tissue abnormalities
Coronoid hyperplasia
- What is aetiology?
- What symptoms?
- Rare - usually chronic history of degenerative joint disease resulting in CP sitting higher than the condyle
- Inhibits opening and translation of jaw
Distinguish degenerative joint disease (osteoarthritis) and rheumatoid arthritis.
DJD:
- Degeneration of joint cartilage and underlying bone
- Erosion, osteophytes (spoke if bone in response to stress), crepitus, limited mouth opening and loss of joitn space
RA:
- Chronic progressive inflammation of joints - NOT normal process of aging
- Abnormal condyle shape w/ severe erosion and sclerosis
Distinguish
- Synovial chondromatosis
- Chondrocalcinosis
- Ankylosis
- Synovial chondromatosis = Formation of cartilage within joint space resulting in small, round radiopaque masses around condyle head
- Chondrocalcinosis = Salt deposit within joint space - very painful and minimal function
- Anklyosis = Fusion of condyle to mandibular fossa - immobility of affected side
What is the difference between adult and children’s TMJ?
o Adult
Clear cortication of condyle with even articular space
o Young
Unclear cortication on articular surface of condyle and wide joint space
What can be seen on imaging of patient’s with RA and juvenile idiopathic arthritis of TMJ?
RA
- Severe erosion
- Severely sclerosis
- Abnormal condyle shape
Juvenile idiopathic arthritis
- Pencil shaped condyle
- Underdeveloped mandible
Explain what happens on OPG if the patient’s
a) Lips are opened
b) Tongue is not presed on palate
c) Not on chin rest
a) Central radiolucency around anterior teeth
b) Radiolucent band on apices of maxillary teeth (palatoglossal airspace)
c) Radiograph shifted upwards - missing maxillary periapical area, cervical vertebrae evident
What is the frequency of taking radiographs for caries assessment in adults and children for low, medium and high caries risk?
Adult
a) Low = 2 years
b) Medium = 1 year
c) High = 6 months
Children
a) Low = 12-18months (if remaining primary teeth)
b) Medium = 1 year
c) High = 6 months
Explain the 6 radiographic assessment points for a dentigerous cyst and what are the ddx?
Dentigerous cyst → Developmental cyst associated with crown of impacted/unerupted tooth
1. Shape: Curved or circular outline; expansile
2. Site: Mandibular third molar > Max third molar > Max canine
3. Size: >3mm in size;
4. Internal structure: Radiolucent
5. Periphery: Well defined cortex
6. Effect on surrounding structures:
Displaces/resorbs adjacent teeth (apical direction of displacement)
Displaces the floor of the maxillary sinus and the IAN
Cortical expansion
DDx:
- Unicystic ameloblastoma
- Ameloblastic fibroma
- OKC
- Rare conditions which are located pericoronally: adenomatoid odontogenic tumour and calcifying odontogenic cysts → Calcified speckles within radiolucency
Most common teeth for these dental anomalies?
a) Fusion
b) Germination
c) Concrescence
a) Canine and incisors
b) Incisors
c) Maxillary 8’s
