Test 1 Review (week 1-4) Flashcards
2 main components of X-ray film
Emulsion (silver halide grain) - records x-ray image
Base - plastic support which emulsion is coated
Function of Vehicle matrix
Suspends halide grains, absorbs processing solutions, protects film from damage (scratching, contamination, pressure)
(5) parts of film (front to back)
Inner paper, dental film, inner paper wrap, led foil backing, outer package
Sized of periapical
Occlusal film (largest), size 0 (small children), size 1 (anterior teeth adult), size 2 (posterior teeth adult)
Intensifying screen
Phosphor fluoresce emit light when exposed to X-ray
More sensitive to x-ray film alone (less radiation)
Composition of intensifying screens
Base (supportive, reflective), phosphor layer (absorb), protective polymeric coat (protection)
Factors affect the speed and resolution of Intensifying screen
Phosphor crystals increased size
Increased thickness of phosphor layer (decreased resolution)
Presence of reflective coating (decreases resolution)
Periapical radiograph (intraoral)
Purpose and view
- Record images of teeth (outlines, portions, démentions) and supporting structures (trabecular bone, lamina dura, periodontal membrane space)
- entire length of teeth plus 3-4mm of supporting tissue beyond the root.
- used ti interrupt normal anatomy and pathology of root and surrounding structures
Bite wing (intraoral)
Purpose and view
- images of crowns and inter-proximal regions of max and man teeth on same film
- limited to 1/3 if teeth and related structures
- purpose to direct cavities
Occlusal radiographs (intraoral)
Images an entire arch (plate or tongue)
Panorex (extraoral)
Jaw to jaw of teeth (all teeth in one frame), straight on
Cephalometric film (extraoral)
Side of head (whole head), side of teeth, jaw lines up
PD length and exposure time for bisecting and paralleling
Bisecting uses short PID
paralleling uses long PID
VA
Length of teeth is reproduced
Foreshadowing- shorter (too much VA)
Elongation - longer (too little VA)
HA
Proximal surfaces of adjacent teeth, placed direct central beam along axis of tooth or through contacts of teeth
Overlapping- too distal
Bite wing placement
2 film in mouth, VA is 8(short), 10(long), HA is parallel to facial surfaces
Intraoral head positions for max and man
Max - tragus to nose parallel to floor
Man - corner of mouth ti tragus parallel to floor
Penumbra definition
Area of un sharpness
Focal spot
X-rays should be emitted from smallest focal spot
Focal spot distance should be increased
Object to film distance
Minimize distance between the object to the film
Paralleling technique
Long axis of the tooth and the Face ID the cone should be parallel
Bisecting technique
Central ray should be perpendicular to the film and long axis of the tooth
Focal spot to film distance
Long as possible
Long cone used for:
Paralleling
Short cone is used for
Bisecting
Foreshadowing
Too steep of VA, reduce VA
Elongation
Too short of VA, increase VA
Film bending
Looks like elongation
