Radiology Flashcards
Name this lesion
Cemento-osseous dysplasia
What are the three different types of fibro-osseous dysplasia?
● cemento-osseous dysplasia (COD)
● fibrous dysplasia (FD)
● ossifying fibroma (OF)
What is the normal look of a parotid gland on a sialograph?
Tree in winter
Name this lesion
Solitary bone cyst
Name this lesion
Dentigerous cyst
What are the different types of locularity when describing radiographic lesions?
- Unilocular (single balloon)
- Pseudolocular (one balloon with multiple compartments but no definitive walls between)
- Multilocular (obvious separate areas dividing ballons)
What will benign lesions do to adjacent anatomy vs what malignant lesions do?
Benign lesions will displace anatomical structures due to slow growth, whereas malignant lesions will destroy anatomical structures by eroding straight through
How can cysts and cyst-like radiolucencies affect teeth?(5)
● displacement/impaction
● resorption
● loss of lamina dura
● widening of PDL space
● hypercementosis
What does hypoechoic mean regarding ultrasound images?
Dark
What is the second most common odontogenic cyst?
Dentigerous cyst
Name this lesion from its radiographic findings:
● SITE: apex of non-vital tooth
● SIZE: variable
● SHAPE: unilocular and rounded
● MARGINS: well-defined and corticated
● INTERNAL STRUCTURE: entirely radiolucent
● TOOTH INVOLVEMENT: yes - associated with root, margins continuous with lamina dura
● EFFECTS: can displace adjacent teeth/structures and long standing lesions can lead to root resorption
● NUMBER: single (but maybe multiple if grossly carious dentition)
Radicular cyst
Where do odontogenic keratocysts usually occur?
Posterior of the mandible
Name this lesion
Odontogenic keratocyst
Name this cyst
Radicular cyst
What is sclerosing osteitis?
A localised area of increased bone density in response to inflammation
What are the three forms of fibrous dysplasia?
● monostotic: single bone affected (most common)
● polyostotic: multiple lesions affecting multiple bones
● craniofacial: typically single lesion affecting multiple (fused) bones
What will be the signs/symptoms of anterior disc displacement with reduction?
Clicking upon opening when the disc is recapsured
What is fibro-osseous dysplasia?
A group of rare, benign, non-inheritable conditions where normal bone is replaced by connective tissue and abnormal bone
What does hyperechoic mean regarding ultrasound images?
Light
What is a residual cyst?
When a radicular cyst persists after loss of tooth (or after a tooth is successfully treated via root canal)
What would you usually use to image salivary glands?
Ultrasounds (if glands are superficial) or MRI
How can cysts and cyst-like radiolucencies affect bone?(3)
● displacement of cortices
● perforation of cortices
● sclerosis of trabecular bone
What decade of life are ameloblastomas most common?
4th-6th
Why does a corticated margin mean indicate the tumour is benign?
It demonstrates that the bone has had time to remodel at the periphery of the radiolucency. This indicates a benign lesion as it only happens when the lesion is slow-growing
What are radicular cysts also known as?
Periapical cysts or dental cysts
Name this lesion based on its radiographic findings:
● attached at the root of a tooth
● thin radiolucent margin continuous with the PDL space of the root but no radiolucent margin separating tumour from root surface
● well-defined
● usually round (but can be irregularly shaped)
● radiopaque (but can be mixed radiodensity)
● displacement of teeth and cortical bone
Cementoblastoma
Why are MRIs good for imaging the TMJ?
no radiation dose and you can see both soft tissue and bony pathology, good for assessing particular disc position, including disc displacement
What is the main reason we do imaging for dry mouth?
To assess for Sjogren’s disease related changes
Name this lesion based on its radiographic features:
● thinned cortices (inferior border of the mandible)
● sparse trabecular bone pattern (general radiolucent appearance)
● thinned lamina dura around teeth
osteoporosis
Name this lesion
Nasopalatine duct cyst
Name this lesion
Cementoblastoma
Name this lesion
Condensing osteitis
What decade of life do dentigerous cysts normally pop up?
2nd-4th
What is the treatment for ossifying fibromas?
Surgical excision (12% recurrence rate)
Name this lesion
Idiopathic osteosclerosis
Why is the contrast for sialography aqueous based rather than oil based?
Makes it easier to excrete from the body and less likely to cause tissue reactions
What are dentigerous cysts always associated with?
The crown of unerupted, or impacted teeth
Name this lesion
Idiopathic osteosclerosis
What does a corticated margin mean?
When there is a well defined margin with a thin layer of dense bone surrounding the whole lesion. A corticated margin suggests a benign lesion
Name this lesion from its radiographic findings:
● SITE: buccal or distal to furcation area of permanent molars (mandible>maxilla)
● SIZE: less than 25mm
● SHAPE: unilocular and rounded
● MARGINS: well-defined and corticated
● INTERNAL STRUCTURE: entirely radiolucent
● TOOTH INVOLVEMENT: yes, involves furcation
● EFFECTS: tilting of the tooth, cortical displacement
● NUMBER: single or bilateral
Inflammatory collateral cyst
What are the four main reasons for radiopacities on a radiograph?(4)
● increased thickness of the bone
● osteosclerosis of the bone
● presence of abnormal tissues
● mineralisation of normally non-mineralised tissues
Where is cemento-osseous dysplasia most commonly found?
The mandible
What are the clinical problems with odontomas?
● impaction of adjacent teeth
● external root resorption
● development of dentigerous cyst
What affect do buccal bifurcation cysts have on teeth?
Tend to push the root of the tooth lingually - so crown tilts buccally
What decade of life are inflammatory collateral cysts most common in?
1st-2nd
What are the key radiographic features of odontomas?
● well-defined radiopacities of varying radiodensity
● areas with radiodensity of enamel
● thin radiolucent margin (i.e. follicle)
What will be the signs/symptoms of anterior disc displacement without reduction?
Limited mouth openingand pain
Name this lesion
Ameloblastoma
What are these all types of?
● dentigerous cyst (and eruption cyst)
● odontogenic keratocyst
● lateral periodontal cyst
Odontogenic developmental cysts
What is the most commonly affected region affected by idiopathic osteosclerosis?
Premolar region of the mandible
What method of imaging is the gold standard for imaging the TMJ?
MRI
What is the most common non-odontogenic cyst?
Nasopalatine duct cyst
Name this lesion
Ameloblastoma
What taste may people with nasopalatine duct cysts taste?
Salty
What is a cementoblastoma?
A rare benign odontogenic tumour of cementum. It occurs around the surface of the root of a tooth (which remains vital)
What are the stages that radicular cysts are formed?
- pulpal necrosis
- periapical periodontitis
- periapical granuloma
- radicular cyst
What is the treatment for cemento-osseous dysplasia?
No treatment needed unless exposed
Name this lesion
Hypercementosis
What decade of life are radicular cysts most common in?
4-5th decades
How do you tell the difference between sclerosing osteitis and idiopathic osteosclerosis?
Sclerosing osteitis will have associated inflammation so you look for a source or signs/symptoms of inflammation (e.g. sensibility test teeth
What are the signs on an ultrasound that a lesion is malignant? (4)
● irregular margins
● poorly defined
● increased/tortuous internal vascularity
● lymphadenopathy
What are these types of?
● radicular cysts (and residual cysts)
● inflammatory collateral cysts
Odontogenic inflammatory cysts
What does heterogeneous mean regarding ultrasound images?
Mixed density
Where do nasopalatine duct cysts occur?
Anterior of the maxilla
Name this lesion
Hyper cementosis
What is an osteoma?
A rare benign tumour of the bone that can occur anywhere but has a predilection for the craniofacial skeleton - particularly the posterior of the mandible
What decades of life are nasopalatine most common?
4th-6th
Name this lesion based on its radiographic features:
● well-defined radiolucency containing varying amounts of well defined radiopaque material (depends on the stage of lesion maturation, fully mature lesions can appear entirely radiopaque)
● lamina dura lost
● PDLs often unaffected
Cemento-osseous dysplasia
What is idiopathic osteosclerosis?
A localised area of increased bone density of unknown cause and no association with inflammatory, neoplastic or dysplastic processes
Name the lesion from its radiographic findings:
ITE: usually posterior of the mandible
● SIZE: any size
● SHAPE: unilocular (10-15%) or multilocular (85-90%) (multilocular have soap bubble appearance)
● MARGINS: well defined and corticated
● INTERNAL STRUCTURE: radiolucent
● TOOTH INVOLVEMENT: no
● EFFECTS: growth not contstrained by cortices (it can grow in any direction it wants); thinning of cortices; can cause “knife edge” external root resorption
● NUMBER: single
Ameloblastoma
What is the normal look of asubmandibular gland on a sialograph?
Bush in winter
Name this lesion based on its radiographic features:
● SITE: mandible anterior to molars
● SIZE: any size
● SHAPE: unilocular or multilocular (when large)
● MARGINS: well defined, poorly corticated, scalloped
● INTERNAL STRUCTURE: radiolucent
● TOOTH INVOLVEMENT: no
● EFFECTS: displacement of cortices, displacement of teeth, occasional external root resorption
● NUMBER: single
Giant cell granuloma
Where do ameloblastomas most commonly occur?
Posterior of the mandible (80%)
Name this lesion from its radiographic findings:
● SITE: around the crown of an unerupted tooth (mandible>maxilla)
● SIZE: variable
● SHAPE: unilocular and rounded but can be scalloped if large
● MARGINS: well-defined and corticated
● INTERNAL STRUCTURE: entirely radiolucent
● TOOTH INVOLVEMENT: yes, continuous with CEJ
● EFFECTS: displacement of the tooth, potential external root resorption of adjacent teeth, variable displacement of adjacent structures
● NUMBER: single
Dentigerous cyst
Name this lesion based on its radiographic findings:
● altered bone margin (radiodensity increases as lesion matures)
● bone enlarges but maintains rough anatomical shape
● margins indistinct and blend into adjacent bone.
Fibrous dysplasia
Name this lesion from its radiographic findings:
● SITE: commonly posterior of the mandible
● SIZE: variable but can get very large
● SHAPE: pseudolocular or multilocular and scalloped
● MARGINS: well-defined and corticated
● INTERNAL STRUCTURE: entirely radiolucent
● TOOTH INVOLVEMENT: no (but often next to one)
● EFFECTS: marked expansion within trabecular bone in contrast to limited displacement of cortices (basically can get pretty big in one or two dimensions before they push up against denser bone); minimal displacement of adjacent teeth; external root resorption
● NUMBER: single (but can be multiple if syndromic)
Odontogenic keratocyst
What is the main dental issue with hypercementosis?
It makes extractions much more difficult
What is a locule on a radiograph?
A discrete compartment like a balloon
What is sialography?
When iodinated radiographic contrast is injected into salivary ducts to look for obstructions
What does homogeneous mean regarding ultrasound images?
Uniform density
Name this cyst
Inflammatory collateral cyst (paradental)
What decade of life are odontogenic keratocysts most common in?
2nd-3rd
Name this lesion from its radiographic findings:
● SITE: always anterior of the maxilla in the midline
● SIZE: usually between 6mm-30mm in diameter
● SHAPE: unilocular and rounded and symmetrical (can look heart-shaped)
● MARGINS: well-defined and corticated
● INTERNAL STRUCTURE: entirely radiolucent
● TOOTH INVOLVEMENT: no but next to incisor roots
● EFFECTS: displacement of incisors and palatal expansion
● NUMBER: single
Nasopalatine duct cyst
What is the most common odontogenic tumour?
Ameloblastomas
What are the dental radiographic features of Paget’s disease?(3)
o Migration
o Hypercementosis
o Loss of lamina dura
Name this lesion from its radiographic features:
● osteolysis (breakdown of bone) and osteosclerosis (thick bone from scarring) resulting in a varied mixture of radiolucent and radiopaque areas
● irregularities on inner/outer aspects of cortical bone
● sequestration of bone (separation of bone)
● periosteal bone reaction (primarily osteomyelitis)
● loss of lamina dura around teeth
● pathological fracture of bone
Either osteomyelitis or osteonecrosis
What are the signs on an ultrasound that a lesion is benign? (4)
● well-defined
● encapsulated
● peripheral vascularity
● no lymphadenopathy
What does a moth eaten radiolucency suggest?
Malignancy
What is osteoporosis?
Decreased bone mass
Name this lesion from its radiographic findings:
● well defined radiopacity (can have slightly radiolucent internal areas)
● no radiolucent margin
● variable in shape
● size usually less than 2cm
● No displacement of teeth
● No effect on PDL
Idiopathic osteosclerosis
What is hypercementosis?
An excessive deposition of cementum around the root of a tooth
What size follicular space would you consider a radiolucency is a dentigerous cyst and not dental follicle?
Larger than 5mm (follicular space is normally around 2-3mm)
Name this lesion based on its radiographic findings:
● single or multiple teeth involved (involving either all the root or just a section)
● radiopacity continuous with the root surface
● PDL space of tooth extends around the periphery
● margins often smooth but can be irregular
Hypercementosis
What are the common oral presentations of Garner’s syndrome?(4)
- Multiple osteomas
- supernumeries
- impacted teeth
- multiple areas of idiopathic osteosclerosis
Name this lesion based on its radiographic findings:
● rounded expansile lesion in which effected teeth are displaced and may be resorbed
● ranges from entirely radiolucent to completely radiopaque (radiodensity depends on the stage of lesion maturation)
● margins usually well defined
● surrounding bone may be sclerotic (thick)
Ossifying fibroma
What are the three phases that you image on sialographs?
- Pre-contrast
- Contrast/filling phase
- Emptying phase (5 mins after)
Name the lesion from its radiographic findings:
● SITE: often premolar/molar region of the mandible
● SIZE: any size
● SHAPE: multilocular and scalloped (maybe soap-bubble appearance)
● MARGINS: well-defined; thin corticated margin
● INTERNAL STRUCTURE: radiolucent
● TOOTH INVOLVEMENT: no
● EFFECTS: extends into inter-radicular spaces but larger lesions displace teeth; initially expands in the trabecular bone before displacing cortices
● NUMBER: single
Odontogenic Myxoma
What causes a dentigerous cyst?
Cystic change in the dental follicle
What are radicular cysts always associated with?
A non-vital tooth
Name this lesion based on its radiographic findings:
● SITE: typically posterior mandible
● SIZE: usually less than 30mm
● SHAPE: unilocular or pseudolocular; scalloped (may extend into interdental spaces with finger-like projections)
● MARGINS: variable
● INTERNAL STRUCTURE: entirely radiolucent
● TOOTH INVOLVEMENT: no
● EFFECTS: typically none, rare displacement of teeth
● NUMBER: single
Solitary bone cyst
Name this lesion
Cementoblastoma
What are bony septae on a radiogaph?
Lines going through the radiolucent lesion that make it look webbed or bubbled - the lines can be curved or straight, prominent or faint and thin or coarse
