radiographic interpretation and CBCT images Flashcards
system of examination
8
symmetry
margins
bone consistency
dentition
supporting bone
any other features?
summary
proposals
symmetry and margins here?
M 19
superimposition of petrous temporal bone (common in occipitomeatal view)
left cloudy sinus
* straight upper margin
* definition (cortication – white margin)
if something inside the sinus that is expanding would expect it to have a curved upper margin
straight, slightly curves at either side – suggests it is a liquid meniscus
* sign that is fluid/pus related to inflammatory sinus disease
5 points to go through when discussing any other features of note in radiogrpah
Radiolucent or radiopaque
site, shape, size
margins
other structures -
* ? aetiology, and effect
provisional/differential diagnosis
radiolucent
loss of previously opaque material (bone, teeth)
radiopaque
increased attenuation of x-ray beam
usually unnatural substances in person – e.g. metal restorations, piercings
natural tissues tend to only show radiopaque when there has been a change to them
* increased density e.g. cortical bone Vs cancellous bone
* increased thickness e.g. overlapping teeth Vs abutting teeth
* alteration e.g. soft tissue calcification
* soft tissue within an air space
possible sites of radiographic findings
5
teeht
alveolus
basal bone
other bones
extra-osseous
possible shape of radiographic findings
4
circular, oval (expanding evenly)
Unilocular (simple shape, not necessarily friendly)
multilocular – scalloped margin or internal divisions, variable appearance
Irregular (concerning appearance)
size of radiographic findings can link to
length of time present - not reliable
margins of radiographic findings can be
well defined
* corticated (has to keep remodelling, slow growing, like a wrapper around the lesion)
* not corticated
ill-defined
radiographic findings relation to other structures can be
possibly aetiological
or have an effect on them
aetiolgical relationship possibilities for radiographc findings
apex of a tooth - ? vital , check clinically
* necrotic pulp, bone responds to this
* cysts, periapical periodontitis
crown of a tooth
* unerupted crown has reduced enamel epithelium around it – can undergo pathological change
possible effects a radiographic finding can have on other structures
4
no effect
displacement
* indicates something growing slowly, bone needs to remodel
* but if aggressive malignant – can grow rapidly, destroying bone and moving teeth with it on its borders, usually have other features of malignant lesions
expansion
* slow growing
resorption
* more aggressive – body not able to set up response to it
possible effects a radiographic finding can have on other structures
4
no effect
displacement
* indicates something growing slowly, bone needs to remodel
* but if aggressive malignant – can grow rapidly, destroying bone and moving teeth with it on its borders, usually have other features of malignant lesions
expansion
* slow growing
resorption
* more aggressive – body not able to set up response to it
radiological sieve for provisional/differential dx
12
- normal
- developmental
- traumatic
- inflammatory
- cystic
- neoplastic (benign and malignant)
- osteodystrophy
- metabolic/systemic
- idiopathic unsure why it is
- iatrogenic caused by tx by HCP
- foreign body
- artefact
work throught this list from top to bottom – yes/no/maybe
any other features on this PA
radiolucent
* maxilla, circular, approx. 1 cm.
* well-defined, corticated margins
* related to apices 25 and ? 26/7
provisional/differential diagnosis ?
* Extension of maxillary sinus
* Odontogenic cystic lesion (relating to non-vital tooth – old inflammatory cyst relating to tooth that was extracted)
If chance finding and asymptomatic -leave and radiograph 6months assess
discuss
Deficient margins and deficient RCT
Multiple restorations in 32-42
RCT 31 & 41, extends to apex 31, but short 41 by ~ 4mm
Periapical radiolucency 41, ~ 8mm diam., well-defined but not corticated (possible sign of infection, cortication loss in infection) but here due to bone resorption
Diag. ? Radicular cyst or periapical granuloma
discuss
Secondary caries or deficient margins ? and ?lesion
22 RCT, obturation variable & many materials used – inadequate
Well-defined periapical radiolucency, margins not fully shown, ~ 1cm diam.
Radiolucencies around margins restorations 21D & 22 M
* Leaking restoration with secondary caries possible
discuss age and IDC position in this lesion of mandible
developing M3M, crown calcified – child
With large mandibular lesion that is well developed, cortical margin, breaches roof of IDC
Displacement of LHS IDC – shows slow going, long standing lesion
discuss abnormality in OPT of female 16y
25 and 26 together at crowns, apart at roots – not what expect in 16y – possible lesion?
Can only see margin due to hard palate superimposition
CBCT – explanation
* Frontal section slice – looks like a lesion with bony margin
* Coronal view – can see antral septum, thin bone sticking into sinus – creates illusion of lesion but it is just a low sinus
‘conventional’ CT
- x-ray source, thin fan shaped beam of x-rays
- corkscrew dectectors round pt
- connect to computer
- long axis of pt, thin slices
- can have axial, coronal (front to back), sagittal (side to side)
- high dose of radiation
CBCT
Lower radiation dose
* X-ray beam produced is a cone shape (not thin fan beam)
* more area needed for detector
* Only round a pt once
Specifically hard tissue seen (CT is hard and soft)
3D view so can see whole area for tx planning
clinical indications for CBCT
9
implant planning
impacted teeth (normal and supernumeraries)
* Location
* Relations, e.g. inferior alveolar canal
* ? related other teeth, e.g. root resorption (teeth viable still, can teeth be moved to resolve)
pathology – cystic lesions, infections, benign tumours
orthognathic surgery
hypodontia
Implant planning
cleft palate – bone defects
dental abnormalities – dilaceration, double teeth
endodontic problems
autotransplantation
3 main general principles needed for radiographic exposure
justification of an individual exposure
optimisation
dose limitation
- (1) (b) A person must not carry out an exposure unless it has been justified by the practitioner as showing a sufficient net benefit giving appropriate weight to the matters set out in paragraph (2)
(2) The matters referred to in paragraph (1)(b) are—
* the specific objectives of the exposure and the characteristics of the individual involved;
* the total potential diagnostic or therapeutic benefits, including the direct health benefits to the individual and the benefits to society, of the exposure;
* the individual detriment that the exposure may cause; and
* the efficacy, benefits and risk of available alternative techniques having the same
objective but involving no or less exposure to ionising radiation.
A history and clinical examination are the only acceptable means for determining that the most appropriate, and necessary, radiographic views are requested.
EADMFR Basic Principles on the use of CBCT
20 basic principles, some familiar and similar to general principles, others specifically related to CBCT:
- Use only when question cannot be answered adequately with lower dose method
- If evaluation of soft tissues required, ? Medical CT or MRI (e.g. cancer pt)
- Use smallest volume compatible with clinical situation
- Choose** resolution compatible with clinical situation**
Bigger volume = bigger dose
Bigger resolution = bigger dose
axial view
standing under and looking up
their right is our left
coronal view
from front of pt
sagittal view
from side
slices of CBCT can make
panoramic style image
