Dental & Face Flashcards
- Which of the following most favours ameloblastoma compared with odontogenic keratocyst?
A. Growth in AP direction
B. Non-expansile
C. CT 40-50 HU
D. High SI on T2
E. Growth in buccolingual direction
E. Growth in buccolingual direction
Ameloblastomas grow in the buccolingual direction and are expansile
(MSK) 39) A young man is assaulted and attends accident and emergency with a painful left mandible and inability to open and close his jaw without pain. Radiographs show a simple linear fracture through the left body in the parasymphyseal region. A second fracture is most likely to be seen at which of the following sites?
a. ipsilateral condylar neck
b. ipsilateral angle
c. symphysis menti
d. contralateral body
e. contralateral condylar neck
e. contralateral condylar neck
The mandible is best considered as a closed ring, and as such approximately half of all mandibular fractures are bilateral and multiple.
The majority occur at the angle, and a significant portion occur at the condylar neck, a common pattern of injury being an ipsilateral body fracture from a direct blow, with a contralateral angle or condylar neck fracture due to transmitted rotation force compressing that side.
Fractures of the condylar neck have a limiting effect on the opening and closing of the jaw and can be missed radiographically.
Fractures in the midline are also subtle and account for a significant minority.
A flail mandible occurs when the anterior support for the tongue is lost due to a bilateral fracture. This injury carries the risk of the tongue prolapsing posteriorly and occluding the airway.
77) A 31-year-old woman presents with a painless mass involving the right side of the mandible. Radiographs show a well-defined, lucent lesion. Which of the following additional findings favour a diagnosis of ameloblastoma over a radicular cyst?
a. absence of matrix mineralization
b. location at the symphysis menti
c. location at the root of a tooth
d. soap-bubble appearance
e. rim of cortical bone
d. soap-bubble appearance
Both ameloblastoma and radicular cysts most commonly present in the third to fifth decades of life as a painless lump, often as an incidental finding.
Neither typically shows matrix mineralization.
Ameloblastoma represents 10% of all odontogenic (developing during or after the formation of teeth) tumours, with the majority located in the posterior body or ramus.
They are frequently associated with the crown of an impacted or unerupted tooth.
They can vary in radiographic appearance, an expansile, multiloculated lesion being typical.
They are often resected due to locally aggressive infiltration.
Radicular cysts are unilocular with a rim of cortical bone and usually develop at the root apex of a carious tooth as the end stage of the inflammatory process.
92) A 40-year-old male presents with pain in the jaw associated with dental caries. An orthopantomogram demonstrates a lytic lesion of 1 cm in diameter, associated with the apex of a carious tooth. The lesion has a thin rim of cortical bone and there is some resorption of the root. What is the likely diagnosis?
a. ameloblastoma
b. odontogenic keratocyst
c. dentigerous cyst
d. radicular cyst
e. odontoma
d. radicular cyst
A radicular cyst is the commonest type of cyst in the jaw and is associated with the apex of a tooth. It may displace teeth and cause mild root resorption.
Ameloblastoma (adamantinoma of the jaw), odontogenic keratocyst and dentigerous cyst are all associated with the crown of a tooth, usually unerupted, and can be difficult to distinguish from each other on imaging alone. They are all odontogenic with no mineralization, and may be large and expand the mandible.
Odontomas are the commonest odontogenic mass (67%) and show mineralization. They are seen in 10–20 year olds presenting with single or multiple, tooth-like masses.
42 An adolescent presents to A&E after trauma and facial radiographs are taken. No fracture is seen, but incidental note is made of a cystic lesion, related to crown of an unerupted tooth. It is unilocular. What does it represent?
(a) Radicular cyst
(b) Dentigerous cyst
(c) Primordial cyst
(d) Aneurysmal bone cyst
(e) Osteoclastoma
(b) Dentigerous cyst
This is most likely to be a dentigerous cyst, which occurs when there is cystic degeneration of tooth enamel before eruption. They are usually unilocular and (unlike the more common radicular cyst) are intimately related to the crown.
@# 7 A 30 year old man with learning difficulties presents· to A&E after suffering facial injuries. An orthopantomogram is performed and demonstrates a multi-locular radiolucent lesion in the angle of the mandible. He suffered from multiple carcinomatous lesions of the skin in childhood. What is the most likely diagnosis?
(a) Odontogenic keratocyst
(b) Dentigerous cyst
(c) Inflammatory odontogenic cyst
(d) Ameloblastoma
(e) Multiple myeloma
(a) Odontogenic keratocyst
This patient suffers from Gorlin-Goltz/ basal cell naevus syndrome, associated with multiple cutaneous basal cell carcinomas during childhood, odontogenic keratocysts, ectopic calcifications, and multiple skeletal anomalies. Mental retardation is another recognized association. All of the above answers above can present as cystic lesions of the jaw.
@# 48 Which of the following is not involved in a Le Fort type II fracture?
(a) Pterygoid plates
(b) Orbital floor
(c) Anterior wall of the maxillary sinus
(d) Postero-lateral wall of the maxillary sinus
(e) Medial wall of the maxillary sinus
(e) Medial wall of the maxillary sinus
The medial wall of the maxillary sinus is spared in a type II fracture.
The pterygoid plates are involved in all Le Fort fractures.
- A 38 year old gentleman presents with a dull ache in his jaw. There is minor swelling over the left mandible. Plain radiographs demonstrate an expansile, multilocular, radiolucent lesion with internal septations involving the left body of the mandible. It is associated with an impacted tooth. CT shows infiltration of the adjacent soft tissues. There are no discernable foci of calcification. What is the most likely diagnosis?
a. Odontogenic myxoma
b. Dentigerous cyst
c. Odontogenic keratocyst
d. Ameloblastoma
e. Periapical cyst
- d. Ameloblastoma
Ameloblastoma (adamantinoma of the jaw) is a benign, locally aggressive lesion that occurs mainly in patients between 30 and 50 years of age.
They are found in the mandible (75%) and the maxilla (25%) and are often associated with an impacted/unerupted tooth.
When in the mandible, they typically occur in the region of the molars/angle of the mandible.
Typically, ameloblastomas are radiolucent lesions that contain septa or locules of variable size, which produce a honeycombed appearance.
The margin is usually well defined but when large it can produce jaw expansion with perforation of the cortex.
They may infiltrate adjacent soft tissues and show local recurrence following excision.
Ameloblastomas may be unicystic but these tend to occur around the age of 20 years and there is also a very rare malignant variety which can cause lung metastases.
Odontogenic keratocysts, dentigerous cysts, odontogenic myxomas and periapical cysts are invariably unilocular.
QUESTION 16
@# A 21-year-old man has facial and mandibular radiographs following minor trauma. These show no evidence of fracture, however there are multiple dense bony lesions arising from the paranasal sinuses and the angle and ramus of the mandible. These lesions are entirely asymptomatic. Which one of the following conditions may be associated with these findings?
A Gardner’s syndrome
B Gorlin-Goltz syndrome
C Juvenile polyposis
D Klippel-Feil syndrome
E Turner’s syndrome
A Gardner’s syndrome
Multiple maxillofacial osteomas are a feature of familial adenomatous polyposis (or Gardner’s syndrome). They precede the colonic polyposis.
@# QUESTION 40
A 14-year-old girl with a kyphoscoliosis has multiple skin lesions which have been characterised as basal cell tumours. In addition she has had investigations which have revealed calcification of the falx and several bifid ribs. Which of the following findings would be most likely on a dental panoramic radiograph?
A A large well-defined lucency inferior to the inferior alveolar canal
B Multiple ill-defined lucent lesions
C Multiple sclerotic lesions, particularly around the angle of the mandible
D Multiple small periapical lucencies
E Multiple well-defined multiloculated lucencies
E Multiple well-defined multiloculated lucencies
This is Gorlin-Goltz syndrome, in which there are multiple odontogenic keratocysts
@# QUESTION 45
A 24-year-old woman presents to her GP with jaw stiffness and headaches. Her partner complains that she grinds her teeth during the night. She attends for an MRI scan to visualise the temporomandibular joints. Sequences are performed with the mouth open and closed. Which of the following radiological findings are most likely?
A Anterolateral displacement of the biconcave articular disc on mouth closing
B Anteromedial displacement of the biconcave articular disc on mouth opening
C Anteromedial displacement of the biconvex articular disc on mouth opening
D Posterior displacement of the biconcave articular disc on mouth opening
E Posterior displacement of the biconvex articular disc on mouth opening
B Anteromedial displacement of the biconcave articular disc on mouth opening
QUESTION 52
A 37-year-old man is brought to the Emergency Department with extensive facial injuries following a bicycle accident. Facial radiographs demonstrate multiple fractures. Which one of the following descriptions of Le Fort fractures is correct?
A Le Fort I: bilateral fractures of the rami of the mandible
B Le Fort I: fractures of the nasal bridge and medial orbital walls
C Le Fort II: bilateral fractures of the rami of the mandible and both zygomatic arches
D Le Fort II: fractures through the nasal bridge, lacrimal bones and medial orbital walls extending to the pterygoid plates
E Le Fort III: fractures through the nasal bridge, lacrimal bones and medial orbital walls extending to the pterygoid plates
D Le Fort II: fractures through the nasal bridge, lacrimal bones and medial orbital walls extending to the pterygoid plates
The Le Fort classification applies to maxillary fractures and none of them involve the mandible.
QUESTION 68
A 31-year-old woman presents with a painless swelling over the left side of her face. A facial radiograph shows a large, multiloculated, lucent lesion arising from the ramus of the mandible. CT confirms a large expansile mass which is corticated, has a soft tissue component and does not contain fluid levels. What is the most likely diagnosis?
A Ameloblastoma
B Aneurysmal bone cyst
C Fibrous dysplasia
D Odontogenic myxoma
E Stafne’s bone cyst
A Ameloblastoma
Ameloblastoma is the commonest odontogenic tumour. It is typically lucent and contains septa or locules, producing a ‘honeycomb’ appearance. It is locally aggressive and therefore requires a large excision margin.
- A 44-year-old woman presents with severe facial injuries following an RTA. CT of the facial bones demonstrates multiple maxillofacial fractures in keeping with a Le Fort configuration. Which of the following statements regarding Le Fort fractures is false?
A. Any combination of Le Fort I, II, and III fractures can occur.
B. Disruption of pterygoid plates from the posterior maxilla is an essential finding in Le Fort fractures.
C. Le Fort fractures by definition refer to fractures involving the maxilla bilaterally.
D. Craniofacial separation is noted in Le Fort III pattern.
E. Le Fort fracture associated with a palate fracture will result in widening of the maxillary arch.
- C. Le Fort fractures by definition refer to fractures involving the maxilla bilaterally.
Separation of all or a portion of the maxilla from the skull base is described as a Le Fort fracture. This can be unilateral when it is associated with sagittal or parasagittal fractures of the palate. Le Fort fractures by definition involve the posterior maxillary buttress at the junction of the posterior maxillary sinus and the pterygoid plates of the sphenoid. This may be either through the pterygoid plates or through the posterior walls of the maxillary sinus. Once a pterygomaxillary disruption has been identified, the remaining facial buttresses are inspected to identify the type of Le Fort fracture. In Le Fort I fracture, the maxillary arch will move in relation to the rest of the face and skull. In Le Fort II fracture, the entire maxilla will move in relation to the skull base. In Le Fort III, there is complete craniofacial separation. Any combination of Le Fort I, II, and III can occur. Posterior extension of Le Fort fracture into the hard palate results in widening of the maxillary arch and dental malocclusion.
- A 25-year-old woman is brought to the A&E department following an RTA. CT of brain and facial bones are requested for assessment of head and facial injuries. On the CT studies, incidental note is made of dense calcification of the falx cerebri, midface hypoplasia, and prognathism. Multiple cystic lesions are also noted in the mandible, which are associated with cortical expansion. Some of the lesions break through the cortex. Following contrast administration there is minimal peripheral enhancement. What is the underlying mandibular abnormality?
A. Radicular cyst.
B. Keratocystic odontogenic tumour.
C. Dentigerous cyst.
D. Stafne cyst.
E. Ameloblastoma.
- B. Keratocystic odontogenic tumour.
These are benign but locally aggressive developmental tumours affecting adults in the second to fourth decades. They are most commonly located in the mandibular ramus and body, and are associated with an impacted tooth. They may be unilocular or multilocular and often contain daughter cysts extending into the surrounding bone. They can be associated with cortical expansion and erosion. They demonstrate minimal peripheral enhancement with contrast. The presence of multiple keratocystic odontogenic tumours raises the possibility of Gorlin basal cell nevus syndrome, which is an autosomal dominant disorder. Associated features include multiple basal cell carcinomas of the skin, mental retardation, midface hypoplasia, frontal bossing and prognathism, calcification of the falx and dura, and bifid ribs.
