Common Qs Flashcards
Name some methods of optimisation of radiation
Regular CPD
Using a collimator
Training of staff
Positioning, preparation of pt
Using aluminium filter
Focus distance to skin (20cm)
Testing of equipment, servicing and maintenance
Audits
What is optimisation?
Best quality diagnostic image for the lowest dosage to pt
What is justification?
Weighing up the risk v benefits for exposing a pt to radiation
Name some indications for periapical radiographs
- Detection of apical infection/inflammation
- Assessment of the periodontal status
- After trauma to the teeth and associated alveolar bone
- Assessment of the presence and position of unerupted teeth
- Assessment of root morphology before extractions
- During endodontics
- Preoperative assessment and postoperative appraisal of apical surgery
- Detailed evaluation of apical cysts and other lesions within the alveolar bone
- Evaluation of implants postoperatively.
Indications for panoramic radiographs?
- 3rd molar assessment prior to extraction
- Orthodontics
- Mandibular fractures
- TMJ problems (changes in
occlusion/trauma/change in range of motion) - Multiple extractions
- Bony lesions/unerupted tooth which cannot
be fully visualised on intraoral images - In the case of a grossly neglected mouth
Name some disadvantages of panoramic radiography
- Image Quality
- Operator dependant/ patient dependent
- Ghost images and superimposition
- Dose
- Magnification
What is the focal trough?
- A three dimensional area within which structures are reasonably well defined on the final image.
- In the panoramic machine, the focal trough is designed to be horseshoe shaped to correspond to the shape of the dental arches
When positioning for panoramic’s, what do we need to ensure?
- The aim is to ensure that the relevant structures (e.g.: dental arches etc ) are within the focal plane
- Machine consists of patient positional aids i.e.. chin rest, forehead rest, lateral head supports,
bite block. - Laser lights to help align patient correctly
- Mid sagittal plane should be vertical
- Frankfort plane (infraorbital rim to top of ear canal) horizontal and parallel to the ground
- Front incisors biting in the groove of bite block
- Machine is adjusted to the size of patient using callipers or “canine light”
How could we manage a pt needing a DPT who is unable to bite on the bite block?
The patient may not be able to understand/physically able to bite into the bite guide. All modern DPT equipment have several different ways of ensuring the patient is in the correct position eg ‘chin cup’. It may be pessary to keep the teeth apart using a cotton wool roll.
What is cervical burnout?
Radiolucent band that appears around the neck of a tooth.
It’s caused by the difference in density between enamel and dentin, and appears as a clear, well-defined band
