RADIOLOGY Flashcards
On an OPG, you identify an irregular shaped mixed lesion in the angle of the mandible of Q3. The periphery is ill-defined and size of approximately 5cm. Which of the following is LEAST likely? A) Osteomyelitis B) Osteoradionecrosis C) Pericoronitis D) Fibrous dysplasia
C
Explain the frequency of taking BW radiographs in adults and children who are
- High risk
- Moderate risk
- Low risk
Adult:
- High risk: 6 months
- Moderate risk: 1 year
- Low risk: 2 years
Children
- High risk: 6 months
- Moderate risk: 1 year
- Low risk: 12 - 18 months in primary dentition and 2 years in adult dentition
Distinguish code 1 and 2 for root caries
Code 1 = < 0.5mm
Code 2 = > 0.5mm
You identify a circular well-defined radiolucent lesion of approximately 25mm at the apex of tooth 23. Clinically, the tooth does not respond to vitality tests. Which of the following is the most likely diagnosis?
A) Cementoblastoma
B) Periapical cemento osseous dysplasia
C) Lateral periodontal cyst
D) Radicular cyst
D) Always associated with non vital tooth
A) Lesion is <20mm
B) Teeth still vital and has radiopaque rim around radiolucency
C) Teeth still vital and usually <10mm
A patient presents at your clinic with pain in the posterior molar region. After taking an OPG, you notice a well-defined radiolucency of around 30mm at the bifurcation of the molars. Which of the following is the most likely diagnosis? A) OKC B) Buccal birfurcation cyst C) Pericoronitis D) Dentigerous cyst
B) Characteristic for radiolucency at the bifurcation of the molars.
A) Possible as appearance variable although commonly occurs at posterior body and ramus with epicentre above IAN and may be pericoronally placed.
C) <10mm in size
D) Associated with crowns (not at bifurcation)
In an adult, which of the following teeth are most likely to be missing in hypodontia? A) Canine B) Central incisor C) Second premolar D) First molar
C)
3rd molars > second premolars > maxillary lateral incisors (permanent dentition)
Last in each series generally affected.
Which of the following is true?
A) Fusion is the joining of two tooth germs by cementum
B) Fusion is more common in permanent teeth
C) Gemination involves two tooth buds attempting to divide
D) Gemination is most common in incisors
D)
A patient has an "outpouching" on his mandibular premolar. Which of the following is the most likely diagnosis? A) Dens invaginatus B) Dens evaginatus C) Talon cusp D) Enamel pearls
B)
A) Not an outpouching
C) Main site is incisors
D) At the furcation of molars
On OPG, you notice local hypomineralisation of the crowns in a patient's premolar teeth. Which is the most likely diagnosis? A) Amelogenesis imperfecta B) Dentine dysplasia C) Turner's hypoplasia D) Dentinogenesis imperfecta
C) Localised to the premolars
All of the following are characteristics of dentinogenesis imperfecta except: A) Bulbous crowns B) Exaggerated CEJ C) Enlarged pulp chamber D) Short roots
C)
Hypercementosis is common in which of the following? A) Down syndrome B) Paget's disease C) Gardener's syndrome D) Crouzon Syndrome
B)
On OPG, you notice a flocculent lesion with well-defined borders in the anterior-canine area. No root resorption is evident and the patient does not report any pain. Which of the following is likely to be the diagnosis?
A) Calcifying epithelial odontogenic tumour
B) Adenomatoid odontogenic tumour
C) Ameloblastoma
D) Cementoblastoma
B)
What are the 3 advantages and 3 disadvantages of an OPG?
o Advantages (compared to a full-mouth series of periapicals)
Broad coverage of facial bones and teeth
Lower radiation dose
Ease of radiographic technique
Can be used in patients with trismus – or who are unable to tolerate intraoral radiography
Quick and convenient technique
Useful visual aid in patient education and case presentation
o Disadvantages
Lower resolution images that do not provide fine details
Uneven magnification, making linear measurements unreliable
Superimposition of anatomic and pathologic details
Requires accurate patient positioning to avoid positioning errors and artifacts
Difficult to image both jaws when patient has severe maxillomandibular
Discrepancy
Distinguish real vs ghost image.
Real image = Lies between film and centre of rotation
Ghost image = Lies between centre of rotation and the xray source
- Always on the opposite side to the real image
- Located higher than the primary object
Which of the following is false? A) CT scan uses a detector ring B) CBCT is a single rotation C) CBCT has a flat panel D) CT scan has a cone-shaped beam
D)
Explain the relationship between frame rate and image quality, time of scan and radiation dose.
↑ Frame rate
Better image quality
Longer scan
Higher radiation dose
↓ Frame rate
Increased artefacts
Shorter scan
Lower radiation dose
After taking an OPG, you notice that there is excessive curvature of the teeth. Which of the following is most likely the film fault? A) Chin is too high B) Chin too low C) Patient is slumped D) Chin is not on chin rest
B)
What is the effective dose limit and occupational dose limit each year?
o Effective dose limit w/o adverse effects < 50mSv/year
o Occupational dose limit <20mSV/year averaged over 5 consecutive calendar year
An OPG shows a well-defined round radiolucency in the retromolar area of the mandible. It’s <1cm and associated with the crown of a molar
What are your differential diagnoses?
Pericoronitis
Paradental Cyst
Dentigerous Cyst
You take an OPG and as its processing you notice there is an oval shadow affecting the middle of the image - overlying the crowns of the anterior teeth
What fault could have caused this?
Pt. lips not being closed - no soft tissue density to pass through so there is a change in the opacity in that area
An OPG shows a well-defined corticated radiolucency in the posterior mandible above the IAN. It is a large lesion with a scalloping/curved outline.
Clinically there has been no bony expansion or evidence of swelling
What is your primary Dx and your Ddx
OKC
Dentigerous cyst - if attached to the CEJ/covering crown
Ameloblastoma - generally has bony expansion
Odontogenic Myxoma - staight/thin “tennis racket” septae are characteristic
Simple bone cyst - ill-defined borders and generally has bony expansion/affects cortical plates
Which benign tumour of the jaws has a characteristic “driven snow” appearance radiographically
A. Calcifying Epithelial Odontogenic Tumour
B. Cementoblastoma
C. Adenomatoid Odontogenic Tumour
D. Odontogenic Myxoma
A
What are the common peripheral radiographic features of malignant conditions?
Ill-defined Lacking cortication Absence of encapsulation Infiltrative pattern No respect for anatomical boundaries
What is Garrington’s sign?
Irregular widening of lamina dura
