Dental Radiography Flashcards
Types of X-Ray Receptors
Traditional Film
Phosphor Storage Plates (PSP)
Direct Digital
What are the parts of a Traditional Film packet?
- Outer Plastic/ Vinyl/ Paper wrapping (protects film from saliva)
- Black Paper wrapping (protects emiulsion)
- X-ray film (sensitive component)
- Lead foil/ sheet ( prevents backscattering of radiation reduces patient exposure)
What way does the film go in the mouth?
The coloured side goes toward the teeth and the white part is facing the cheek
White in sight and Dot in slot
Film Base
Polyester plastic, provides support and strength
Adhesive Layer
Attaches emulsion to base
Film Emulsion
A mixture of gelatin and silver halide
crystals (sensitive to radiation)
Protective Layer
protects emulsion from damage.
Intra Oral
Placed inside the mouth
Extra Oral
Taken on the outside of the mouth
Duplicating
Produces two copies of the same image
(special film)
What is a Latent image?
A latent image is a fil that has been exposed to radiation but has not been deveopled yet
what are the different film speeds
ratings from A-F
D,E,F are only film used for intraoral radiology
Screen
Film placed between 2 intensifying screens for exposure
Non-screen
Film is exposed directly to x-rays, requires longer
exposure time, NOT recommended for use in
dentistry.
Film Storage
Film must be kept in a cool, dry place
* Must be stored in an area adequately shielded
from radiation
* Film MUST be used before expiration date
(can cause fogged films)
Digital Radiography
Digital imaging eliminates chemical processing and
hazardous wastes (lead foil, chemicals)
* Requires LESS Radiation to expose
* Allows for digital enhancements, measurements and
corrections
* Images can be electronically transferred to other
health care providers
* Sensors are VERY expensive
Phosphor Storage Imaging (PSP)
- Thin, flexible plate that is covered in phosphor crystals
- Plates are the same size as conventional x-ray film
- Phosphor layer stores energy of x-ray photons
- After exposure plates are placed into a scanner
- Scanner laser reads the latent image and converts it to a digital image
- Films are exposed to a bright light to ”erase” the image
Intraoral Radiography
Periapical (PA)
Used to view entire tooth (root and crown) Size#2 are used for posterior and Size #1 for Anterior.
Intraoral Radiography
Interproximal
(BWS)
Used to detect interproximal (between the teeth) caries and bone loss. Can be taken vertically and horizontally.
Intraoral Radiography
Occlusal
Used to determine tooth development, can determine if patients are missing teeth. The film is placed in the mouth horizontally and the patient down bites on the film like a cookie.
Producing Diagnostically Acceptable
Radiographs
- All required anatomy must be present.
- Contrast also referred to as grey scale.
- Density also referred to as darkness.
- Sharpness.
- Magnification.
- Distortion.
The Paralleling Technique
- Receptor is parallel to long axis of tooth
- X-ray beam is perpendicular to the long axis of the tooth
- Face of cone is parallel with the face of the film.
- Common errors: incorrect placement and alignment.
Paralleling Technique Steps
- Explain procedure to the patient.
- Position receptor close to midline for a maxillary PA and between the tongue and teeth for a mandibular exposure.
- Position receptor centered on the required anatomy/teeth.
- Position receptor parallel to the long axis of the teeth.
- Seat bite block on the incisal edge or occlusal surface for support.
- Ask patient to relax and slowly close down to support the XCP holder, and breath slowly through their nose.
