CBCT Flashcards
What are the problems with Cone beam CT?
1.Movement artifact – shown as multiple lines– patient need to be very still
2.No soft tissue resolution – use convetional CT
How much of the radiation does CBCT produce?
75 uSv (microSieverts)
What is another machine that can be used to observe soft tissues as well?
MDCT – multi detector computer tomography – 200 microSieverts
Do you need a radiologist?
Yes because:
1.It provides a provider number to allow Medicare rebates
2.Review of all areas of the scan
3.Removes much of the legal responsibility
What are the medicolegal responsibilities of dentist in terms of radiology?
Dentists who record OPG radiographs must take responsibility for all non-dental diagnosis from such images or alternatively have them assessed on referral by an oral radiologist or medical radiologist and include this cost in their estimate of fees to the patient.
What are the two different groups of unwanted effect after CBCT?
1.Deterministic – result of cell killing
2.Stochastic – result from cell modification
What is the DOT DAM principle of radiology?
Don’t Order Tests that Don’t Affect Management
What is the ALARA principle of radiology?
As Low As Reasonably Achievable
What type of CBCT available for jaws?
Small field and whole jaw
What are the different types of artifact available on CBCT?
1.Beam hardening – streaks arising from very dense objects
2.Scatter – soft streaking
3.Motion – blurry or double vision
4.Poor machine care – multiple artifacts
5.Faulty detector – rind around the jaw
What colour are the tissues on CBCT?
White is dense and black is low density
How do you view a CBCT?
1.From down to up
2.From outside to inside
3.From Left to right
What are the common accidental findings on CBCT?
1.Dense bone Islands
2.Torus
3.Osteomas
4.Degenerative Joint Disease
5.Chondrocalcinosis
6.Synovial osteochondromatosis
7.TMJ Dysfunction
8.Sinus pathology
9.Nasal septum pathology – including different sinusitis, and mucucoel
10.Nasal cycles
What is a good rule of thumb when understanding where the pathogloy comes from?
1.If above the mandibular canal – possibly dental origin because only non-dental related pathology occurs bellow the mandibular canal
2.Non-dental lesions are move common in tooth bearing areas
How do you examine at radiographic boney lesions?
1.Location
2.Margin – well-defined or illdefined
3.Zone of transition – short or long
4.Periosteal reaction
5.Internal matrix
6.Single vs multiple
7.Relationships to the joints
8.Effect on soft tissue
What are the features of non-aggressive lesions?
1.Well-defined margin
2.Often schlerotic border
3.Short zone of transition
4.Little or no periosteal reaction
5.Bone often thinned and/or expanded
6.Minimal effect on soft tissues
What are the feature of aggressive lesions?
1.Poorly-defined margin
2.Long zone of transition
3.Periosteal reaction may be extensive
4.Bone often destroyed
5.Permeative appearance
6.Soft tissue involvement is common
What is the common appearance of the radicular cyst?
Lesion consists of a lucent centre and a thin, well-defined sclerotic rim. Cortical bone destruction may occur if cyst becomes too big.
What is the common appearance of the dentigerous cyst?
Lesion uniformly lucent with a thin, well-defined sclerotic rim attached to the cemento-enamel junction.
What is a common appearance of a odontogenic keratocyst?
Odontogenic keratocyst is a well-defined sclerotic which causes less jaw expansion and grows along the jaw bone.
What is a common appearance of an ameloblastoma?
Has aggressive growth characteristics. Typically well-defined and radiolucent. Cause root resorption, tooth displacement and bone expansion. Floating tooth appearance.
What is a common appearance of an adenomatoid odontogenic tumour?
Anterior mandible, well defined with corticaed border. Tooth displacement is common, root resorption is uncommon.
What is a common appearance of cemento-ossifying fibroma?
Mandible, fibrous capsule gives a thin raiolucent halo. Rapid expansion and tooth displacement. May contain abnormal bone and cementum like tissue.
What is a common appearance of cementoblastoma?
Slow growing lesion full of cementum like tissue. Attached to root apex. Well-defined with cortical border.
What are giant cell lesions?
Anterior to first molar. Slow growing with well-defined margin. Some cortical expansion can occur.
What is nasopalatine cyst?
A defined radiolucency that occurs in the palate
What is a Stafni’s bone defect?
It is a salivary inclusion cyst. A well-defined oval lucencies anterior to angle of mandible.
What is the common appearance of eosinophilic granuloma?
Solitary lesion, well-defined bu non-corticated with irregular margins. DESTROYS BONE AND LEAVES THE FLOATING TOOTH APPEARANCE. Periosteal new bone formation is common.
What is common appearance of periapical cemental dysplasia?
At apex bone is replaced with fibrous material. Lesion persistent after extraction.
What is a common radiographical appearance of squamous cell carcinoma?
Smoking adults. Ill-defined, permeative lesion. Spread localy and lymph nodes. Destroys bone.
What is a common appearance of mucoepidermoid carcinoma?
Well-defined border in posterior body or angle of mandible.
What is a common appearance of osteogenic sarcoma?
Posterior mandible. Painless swelling. Ill-defined borderd\s. “Sun-ray” spiculation appearance. Breaks bone.
What is the common appearance of metastases to the jaw?
Usually from renal, breast, lung, colon and prostate. Affect posterior mandible. Ill-defined, lytic lesions with clear bone destruction.
What is the common appearance of osteomyelitis?
PAIn _ subtle changes in bone density. Bone destruction with sequestration formation.
What is the common appearance of MRONJ?
Pains, swelling and draining sinuses. Bone destruction. Periosteal reaction is common.
What are the 7 signs of IAN involvement?
1.Darkening of the roots
2.Interruption of the white line
3.Diversion of the mandibular canal
4.Deflection of the roots
5.Narrowing of the roots
6.Dark and bifid roots
7.Narrowing of mandibular canal
What is the common appearance of fibrous dysplasia?
Genetic disorder resultin in replacing of bone with fibrous tissue. Ill-defined margin and grounnd-glass appearance. Only condition that can displace the mandibular canal superiorly.
