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