Radiopacities Flashcards
Why do radiopacities occur on radiographs?
Increase in tissue or of an object (thickness) in the line of the X-ray beam
Increase in density of the soft tissue (which is of a normal thickness)
List some of the causes of radiopacities on radiographs
The various causes can be divided into-
Artefacts
Normal anatomy
Dental tissue origin
Bony origin
Increased thickness of bone (due to developmental, inflammatory or neoplastic processes)
Increased density of bone (due to inflammatory or dysplastic processes)
Soft tissue origin (antral lesion, soft tissue calcification)
Foreign body, external to the normal tissue
List some artefacts that appear radiopaque on a radiograph
Copper dot (circular radiopacity, occurs when the phosphor plate has been used in the back to front position and as a result the copper dot on the film is projected as a radiopaque circle on the image)
Foreign objects (e.g. glasses)
Cervical spine shadow (occurs due to incorrect patient positioning, as a result of the patient being in a slumped position during OPT scanning)
Ghost shadow of the mandible (an artefact that is inherent to the OPT imaging technique, a ghost shadow of the mandible is a normal radiopaque feature of an OPT)
List some normal anatomical radiopacities
Zygomatic buttress (can obscure PA tissues surrounding posterior teeth)
Coronoid process (on a PA film, we would see a bony projection coming from the inferior aspect of the film)
Lower lip
Nose (anterior PA)
List the abnormalities of teeth that can present as radiopacities
Retained roots
Unerupted or ectopic teeth
Supernumeraries
Abnormality of tooth development
Odontomes
Hypercementosis
What is a pulp stone?
Calcification within the pulpal tissues (pulp space/root canal)
How do pulp stones arise?
Can occur as idiopathic calcifications in pulpal tissues
Or may be related to longstanding local irritation e.g., from caries or as a result of trauma
Sometimes associated with various syndromes such as dentinogenesis imperfecta or dentinal dysplasia
What is an enamel pearl?
1/5 types of odontomes (abnormal growths of tooth forming tissues).
Essentially an extra growth of enamel, usually at the furcation region of a multi-rooted tooth. Tends to affect the maxillary molars
How does an enamel pearl present on a radiograph?
Will see an extra radiopacity of a similar density to the enamel around the crown.
Will be situated in the coronal third of the root, often in the furcation region of a multi-rooted tooth
What is hypercementosis?
Excessive deposition of cementum on roots of teeth
Describe the features of hypercementosis
Excessive deposition of cementum on roots so the roots will be quite bulbous
Asymptomatic
On an X-ray, we will see a smooth widening of the roots that is slightly less radiopaque than the adjacent dentine (but still a radiopacity)
The PDL and lamina dura will continue all the way around the outside of the more bulbous root form/cementum
What is an odontome?
Abnormal growth of tooth forming tissue
Benign hamartoma (a disorganised mass of tooth forming tissue, native to its normal anatomical location)
What is a compound odontome?
An abnormal growth of tooth forming tissue which is made up of lots of little denticles (small tooth like structures which have all of the layers of a tooth in correct formation i.e., root canal centrally, surrounded by dentine and then enamel on the outside).
Will look like a little collection of small malformed teeth / mass of tiny teeth
Often associated with failed eruption
What is a complex odontome?
An abnormal growth (disordered mass) of tooth forming tissue
Won’t have normal ordering of the dental tissues. Very irregular mass, where we can’t differentiate between the root canal, enamel and dentine.
Often associated with failed eruption
Describe the features of a cementoblastoma
Benign neoplasm (new growth of tissue occurring outside of the normal homeostatic mechanisms)
Rare
Tend to be seen in the mandibular premolar/molar region
On an X-ray, we will see a circular radiopacity of an abnormal structure of cementum at the apex of a tooth. Usually these lesions will have a radiolucent periphery and be more radiopaque centrally.
Can have sclerotic margins around the outside
Can be quite expansile, often displacing the lower border of the mandible
Often associated with root resorption
Describe the radiographic features of a cementoblastoma
On an X-ray, we will see a circular radiopacity of an abnormal structure of cementum at the apex of a tooth. Usually these lesions will have a radiolucent periphery and be more radiopaque centrally.
Can also have sclerotic margins around the outside
Can be quite expansile, often displacing the lower border of the mandible
Often associated with root resorption of the affected tooth
Describe the features of a calcifying epithelial odontogenic tumour (Pindborg tumour)
Benign swelling or excessive growth of tissue
Rare
Affects the mandible more than the maxilla
Often associated with an unerupted tooth (particularly L8s)
2/3rds of these tumours will have a mixed density, but will become increasingly more radiopaque/dense with age)
Usually have a scalloped margin
Can be expansile
List the soft tissue radiopacities that may present in the maxillary antrum/sinus
Inflammatory change that has caused mucosal thickening of the sinus mucosa
Benign antral cyst/retention pseudocyst
How does a benign antral cyst/retention pseudocyst present on a radiograph?
Well defined, non-corticated, smooth, dome shaped radiopacity in the antrum
Antral floor will be intact
On an X-ray, you observe a well defined, non-corticated band of radiopaque soft tissue that is parallel to the bony outline of the antral/sinus floor. The cortical line of the antral/sinus floor and walls is intact. The patient reports a dull throbbing pain from the UR6. What is the likely diagnosis of the radiopacity observed in the sinus?
Inflammatory change that has caused thickening of the paranasal sinus mucosa
Inflammatory thickening can be related to dental infection. As the patient reports pain from the UR6, it may be that the inflammatory thickening of the sinus mucosa has occurred in response to the PA infection in this tooth
Some radiopacities in the antrum are a cause for concern and require further investigation or referral. What are the red flag signs and symptoms we should look out for?
Signs on imaging-
Bone erosion (absence of corticated margins surrounding the antrum/sinus, indicates that the bone has been eroded by the radiopacity)
Corticated border around the outside of the soft tissue (around the dome shaped benign antral cyst, for example)
Displacement of the antral/sinus boundaries
Symptoms-
Epistaxis (nose bleed)
Unilateral nasal obstruction
Dys- or paresthesia (altered sensation or loss of sensation in the region of the cheek)
Facial swelling (non-odontogenic origin)
List some examples of soft tissue calcifications
Pulp stones
Ligaments e.g. stylohyoid (with age, ligaments can begin to calcify)
Lymphoid tissue/tonsils (tonsilloliths)
Salivary glands (sialolith)
Blood vessels (phleboliths)
Antrum (antrolith)
Nose (rhinolith)
Skin (calcinosis cutis)
Muscle/subcutaneous tissues
Describe tonsilloliths
Little stones within the palatine tonsils, which can project over the ramus of a mandible on an OPT
Describe a sialolith
Stone within a salivary gland
Mainly seen in the floor of the mouth as a radiopacity on a lower occlusal radiograph
May project over the mandible on an OPT
Parotid stones are relatively rare but can be seen along the occlusal plane on an OPT
Describe phleboliths
Little calcifications that occur within blood vessels of a vascular malformation
The blood in these regions won’t be moving very quickly and due to that slow flow, we can get little stones forming
Tend to have a targetoid appearance (central radiopaque area, with a layer of radiolucency surrounding it and possibly another radiopaque area around that)
Generally a few of these stones will be clustered together
How can we localise a radiopacity?
The easiest way of localising is by taking another type of radiograph at a right angle to the first one (PA/OPT paired with a lower occlusal)
If this is not achievable, we can localise by using a different angle for the same type of radiograph and employing the PARRALLAX technique / SLOB rule
What is a dense bone island?
A localised growth of compact bone which extends from the inner surface of the bony cortex
Normal variation of bone
More common in the mandible than in the maxilla
Also known as idiopathic osteosclerosis
What is another term for a dense bone island?
Idiopathic osteosclerosis
What is a tori?
Overgrowth of bone (bony extoses) (primarily compact bone)
Developmental abnormality
In the mandible, tend to develop on the lingual surfaces, usually in the premolar region
In the maxilla, tend to develop centrally or either side of the midline in the posterior hard palate
Will present as bright radiopacities
Inflammatory change in the bone in response to infection can produce radiopacities. List some examples
Sclerosing osteitis (PA radiopacity, very localised to the source of the infection, occurring in response to a low grade chronic infection of the pulp)
Osteomyelitis
Osteoradionecrosis
MRONJ
What is sclerosing osteitis?
Inflammation of the bone that has led to bone hardening (sclerosis) in response to a low grade chronic infection of the pulp.
Proliferative reaction following pulpal necrosis
Occurs in a very localised area, next to the source of infection (PA tissues adjacent to infected tooth)
What is osteomyelitis?
Spreading, progressive inflammation of bone in response to infection
This can be acute or chronic
Affects the mandible more often than the maxilla (potentially due to the maxilla’s better blood supply)
Describe the radiographic features of sclerosing osteitis
Sclerotic bone surrounding the apex of a non-vital tooth (deep caries, RCT/crown, large filling, history of trauma)
Widening of the PDL
Describe the radiographic features of osteomyelitis
Poorly defined moth-eaten appearance of the bone
Subperiosteal bone formation (inflammation of the periosteum leads to the layering of new bone at the periosteum. This deposition of new bone causes the bone to expand. These bone layers can form parallel to each other and parallel to the cortical surface on a radiograph. As a result, we may observe an onion skin appearance of the layers of new bone)
Sequestra of necrotic bone (section of necrotic bone which is no longer attached to the adjacent normal bone, will work its way towards the surface as the body tries to expel the area of necrotic tissue)
Sclerosis (hardening/proliferation) of surrounding bone
What is subperiosteal bone formation?
Where there is infection of the bone, the periosteum can become inflamed.
The inflammation of the periosteum can lead to the layering of new bone at the periosteum (healing inflammatory response to infection). This deposition of new bone causes the bone to expand
These bone layers can form parallel to each other and parallel to the cortical surface on a radiograph. As a result, we may observe an onion skin appearance of the layers of new bone
What is a sequestra of necrotic bone?
Section of necrotic bone which is no longer attached to the adjacent normal bone
Will work its way towards the surface as the body tries to expel the area of necrotic tissue
What is osteoradionecrosis?
Radiation induced damage resulting in bone necrosis
Bone death following radiotherapy
Clinically seen as an area of exposed bone in a location that has either been treated with radiotherapy or been within the radiotherapy field.
Affects the mandible more than the maxilla
Describe the radiographic features of osteoradionecrosis
Similar appearance to osteomyelitis but without a periosteal reaction (less likely to see a periosteal reaction as there isn’t as much of a healing inflammatory response)
Poorly defined, moth eaten area of bone with irregular margins.
Bone sequestra (areas of dead bone breaking away from adjacent normal bone)
Pathological fracture (due to weakening of the bone)
Prominent bony sclerosis
Can resemble bone destruction by a maligned neoplasm (always worth considering whether it could be a recurrent malignancy or a primary malignant tumour as opposed to osteoradionecrosis. Will need a biopsy to confirm this)
What is MRONJ?
Necrosis of the bone arising from complications of medications which reduce bone metabolism e.g. bisphosphonates
Clinically, we observe exposed bone (following XLA/trauma)
Affects the mandible more than the maxilla
Describe the radiographic features of MRONJ
Resembles osteoradionecrosis/osteomyelitis
Poorly defined, moth eaten appearance
Bone sequestra (areas of dead bone breaking away from adjacent normal bone)
Widening of the PDL spaces of adjacent teeth
Prominent bony sclerosis
Delayed non-healing sockets (couple of months after XLA with no evidence of bony infill following XLA)
Reduced periosteal reaction (less likely to see a periosteal reaction as there isn’t as much of a healing inflammatory response)
Describe the features of an osteoma
Arise on the cortical surface of bone as a pedunculated mass (mushroom like)
Usually asymptomatic, although patient may be aware of a lump
Usually a single/lone mass
Multiple jaw osteomas are a feature of Gardner syndrome
Describe the radiographic features of an osteoma
Well defined radiopacity with a smooth outline, arising from the cortical surface of bone
Pedunculated (almost looks like a mushroom coming out of the bone surface)
Homogenous radiopacity
On a PA it will present as a homogenous radiopacity overlying the teeth
Multiple (5 or more) jaw osteomas are a feature of which syndrome? What other symptoms may be observed in patients with this syndrome?
Gardner syndrome
Other associated symptoms include-
Multiple polyps in the colon
Epidermoid cysts
Fibromas
Multiple supernumerary teeth in the jaws etc.
Describe the features of a cemento-ossifying fibroma
Composed of fibrocellular tissue and mineralising material
Benign mixed density lesion which increases in density over time (more dense centrally with a more radiolucent soft tissue capsule at the periphery)
Found in variable locations, but tends to be in the posterior mandible
Can lead to displacement of adjacent structures
Can lead to bony expansion
Describe the radiographic features of a cemento-ossifying fibroma
Round, well defined, mixed density lesion that appears more radiopaque centrally and less radiopaque at the peripheries (where a soft tissue capsule forms)
Adjacent bone may have a sclerotic margin
Becomes increasingly more radiopaque over time
Expansile lesion with the ability to displace associated structures
Describe the features of an osteogenic sarcoma
Primary bone malignancy
Rapidly destructive
More common in other bones, but can occur in the jaws (more commonly in those aged 30-40)
Describe the radiographic features of an osteogenic sarcoma
Early radiographic features are fairly non-specific. May present as a widening of the PDL space initially
Mixed density lesion with a more radiopaque centre
Classically has a sharp ‘sunray’ appearance as bony spicules project at 90 degrees to the bone surface
The sunray appear spreads out from a central source
Bony spicules can appear to extend into the soft tissues
List the 3 subtypes of cemento-osseous dysplasias
Periapical
Focal
Florid
All have similar features but vary in extent
Describe the features of a periapical cemento-osseous dysplasia
Relatively common
Idiopathic
In the early stages, it appears as a radiolucent area at the apex of a vital tooth, unlike PA cyst or granuloma, which occur at the apex of non-vital teeth.
Associated teeth won’t have deep caries or large restorations. Clinically, they will have normal vital responses to sensibility testing
Most commonly occur in the anterior mandible
With maturation, the lesion becomes increasingly radiopaque due to central calcification
Usually, no corticated border around the outside
Most commonly affects Black, Middle aged women
Often mistaken for non-vital teeth but
as the associated teeth are vital, we should not start destructive intervention like RCT, need to consider all things holistically, are there symptoms or indications for loss of vitality alongside the initial radiolucency?
Describe the features of a focal cemento-osseous dysplasia
Mixed radiolucent area associated with one tooth/area.
Central radiopacity with a peripheral radiolucency
As it is seen in one area, it is known as a ‘focal’ COD
Describe the features of florid cemento-osseous dysplasias
A mixed density lesion in 3 or more quadrants is known as ‘florid COD’
Changes throughout the bone can be quite pronounced.
Mixed density appearance with a central opacity and peripheral radiolucency in the PA regions.
Can also get some expansion with these areas, unlike other types.
Describe the features of fibrous dysplasias
Idiopathic
Proliferation of fibrous tissue and resorption of normal bone causing painless enlargement
Develops during childhood (lesions usually become static when skeletal growth stops)
Can affect any bone including the jaws, tibias, femur etc.
70% of cases are monostatic (i.e. they’ll only occur in one bone).
Jaws are commonly affected, usually unilateral
Maxilla more commonly affected than the mandible
Describe the radiographic features of fibrous dysplasias
When fibrous dysplasias first develop, they will have a radiolucent appearance which becomes mottled and then radiopaque with time.
At the mottled / radiopaque stage, the trabecular pattern of bone will appear altered within the affected bone.
At these stages, we will see a glass or orange peel texture to the bone
There will be no clear margin as the abnormal bone merges into the adjacent normal bone with a blended periphery (poorly defined)
Can be expansile
Describe the general features of Paget’s disease
Idiopathic
Disease that affects the elderly
Abnormal maintenance of the bone which presents as slow enlargement of the bones (hats and dentures will no longer fit)
Tends to have a symmetrical pattern of involvement
Jaws are commonly affected (1 in 5)
Maxilla more commonly affected than the mandible
Results in brittle bone, with an increased risk of pathological fracture
Increased risk of osteogenic sarcoma
Patients with Paget disease have an increased risk of which other diseases?
Osteogenic sarcoma
Pathological fracture
Describe the radiographic features of Paget’s disease
There will be a variation in the radiological appearance of these lesions with time.
In the initial stages of the disease, there will be osteolytic areas and later, there will be bony deposition.
In the mandible/maxilla, we would see areas of osteoporosis
With time, the bone will increase in density in these regions, developing a cotton wool appearance
Expansile, enlargement of affected bone
Loss of lamina dura around all teeth located within the affected bone
Hypercementosis
