Caries & Periapical Pathology Flashcards
Justification for radiation exposure?
- selection of appropriate radiograph should be based on patient’s history & clinical examination
- Routine/screening radiograph prescriptions must be based on knowledge of the prevalence of disease
Interpretation of justificatoin for radiation exposure depends on:
- Knowledge of how image is acquired
- Knowledge of anatomy
- Knowledge of disease process
Interpretation of exposure also depends on understanding the effects of:
- Positioning
- Exposure
- Processing
- For digital imaging, the programme algorithms & computer factors
Which radiograph should we take in a particular situation?
ALARP - As Low As Reasonably Practicable
What is dose in relation to the patient?
The amount of radiation absorbed by the patient
How are carious lesions detected?
Detected radiographically when there has been sufficient demineralisation
What type of radiograph is considered to be “gold standard”?
Bitewings
Recommended techniques of radiograph considered for diagnosing caries?
1- Bitewings - usually horizontal
2- paralleling periapicals
Types of bitewings radiographs?
Horizontal and vertical
What are you expecting to see in a radiograph?
- Crowns of the teeth and coronal portion of roots
- Contact points with none or little overlap
- Distinguish layers of teeth
- Overhangs or etc if restoration present
What can be mistaken for caries?
- Cervical burnout
- Lip shadow in premolar region
Limitation of caries diagnosis?
- Overlap
- Technique
- Anatomy
Technique of paralleling periapicals and bitewings:
- Film is parallel to long axis of tooth
- xray beam at 90º to film and tooth
Paralleling technique:
- Film and tooth parallel vertically - if not, distortion may occur
High risk child radiograph taken..
6 months
Moderate risk child radiograph taken..
Annually
Low risk child radiograph taken…
12-18 months deciduous
>= 24 months permanent teeth
Mandible trabeula pattern..
Thick, close together, horizontally aligned
Maxilla trabeula pattern..
Finer, more widely spaced, no obvious alignment pattern
Radiology and peri-radicular disease. The 3 most important features:
- Radiolucent line representing the periodontal ligament space
- radiopaque line representing lamina dura
- Trabecula pattern and density of surrounding bone
These can be lost due to personal variation
Limitation of radiographs due to:
- Contrast
- Resolution
- Superimposition etc.
Radiographic appearance of periapical pathology:
Initial acute inflammation
- no apparent changes or possible widening of periodontal ligament space
Where does the initial spread of inflammation cause:
Loss of lamina dura at apex
Further inflammatory spread..
Periapical bone loss
Initial chronic inflammation leads to..
no bone destruction can be seen or dense sclerotic bone periapically
Long standing chronic inflammation:
Circumscribed, well defined, radiolucent area periapically with sclerotic bone surrounding
What is radiolucency sometimes described as:
Rarefying osteitis
