Exam 2 Flashcards
Periapical Exam
to view entire tooth&surrounding bone,
can examine single tooth or use with other PA or BW for entire dentition&support structure
can be made w/ 3 periapical sizes #0, #1,#2
Min. of 14 PA’s can make up a FMX for most adults
1 film for mand&max incisors
1 film in each canine areas (2 max, 2 mand)
1 film each premolar area (2 max, 2 mand)
1 film each molar area (2 max, 2 mand)
Film holders that can be used with both PA’s & BW are?
Stabe & SUPA
these film holders can have long biteblocks
Following film sequence/positioning
- Max Anterior PA’s
- Mand Anterior PA’s
- Max Posterior PA’s
4 Mand Posterior PA’s
5 Anterior BW - Posterior BW
IntraOral Procedures
Bitewing exam, Periapical Exam, Occlusal Exam
SHADOW CASTING
The radiographic source of light (x-rays) is the focal point in the x-ray tube.
Source
light is the focal point in the xray tube
Receptor
is film or ccd of a digital radiographic sensor
object
oral structures such as bone & teeth
Angulation
description of alignment of entire tooth, tooth roots, or anatomic crown of tooth to a vertical axis in both anteroposterior and lateral planes of jaws.
Principles of shadow casting, Principle 1
xray should be emitted from the smallest source of radiation as possible
(the smaller the focal point the sharper the image)
Principle 2
xray source-to-object distance should be as long as possible
(longer PID& target film distance results in less magnification)
Principle 3
the object-to-receptor distance should be as short as possible
(the closer the proximity of the tooth to film, lesser the image enlargement)
Principle 4
the receptor & long axis of the tooth should be parallel to each other
(if the film & tooth are not parallel, and angular relation is formed and distorted image results)
Principle 5
xray beam should be directed perpendicular to the receptor
to limit distortion the central ray of the xray beam must be perpendicular to the tooth & film
Principle 6
there should be no movement of the tube, film, or patient during exposure
Anterior PA’s
will have the films positioned vertically
Posterior PA’s
will have the films positioned horizontally
Labial Method
all film should have the dot complex
large radiolucent areas of the nasal fossa or the max sinus indicate?
the radiograph is of maxillary area
the DH or DA may interpret radiographic errors such as?
.overlapped contacts, elongated areas/images and artifacts and normal radiographic anatomy
radiographs lose value when?
6 months to a year bc oral conditions change constantly
Manual Processing of dental xrays
1 developing 2 rinsing 3 fixing 4 washing 5 drying
Chemicals can be added in 3 forms which are?
powder, liquid concentrate, ready to use solutions
powder and liquid concentrate must be mixed with distilled water
Developer
to convert exposed silver halide crystals into metalic silver grains
4 chemicals in developer
- developing agents (reducing agents)
- preservative
- activator (alkalizer)
- restrainer
developer contains 2 chemicals
hydroquinone and elone
both chemicals are affected by extreme temp
what does fixer do
stops further film development and establishing image permanently on film by removing unexposed/underdeveloped SHC, hardens emulsion
Preservative ( sodium sulfite)
protects the developing agents by slowing down rapid oxidation rate of developer
Hardening agent
potassium aluminum, shrink and hardens the gelatin emultion
activator (usually sodium carbonate)
provides necessary alkaline medium required by developing agents, softens and swells the gelatin allowing more exposed SHC to come into contact with developing agents
restrainer (potassium bromide)
restrains developer agents from developing unexposed SHC and inhibits the tendency of the solution to chemically fog the film
replenisher
added to developer or fixer in the processing tank to compensate for the loss of volume and strength for oxidation
fixing agent (ammonium thiosulfate or sodium thiosulfate)
removes all unexposed and any remaining underdeveloped silver halide crystals from emulsion
acidifier (acetic acid)
provides the acid medium to stop further development by neutralizing the alkali of the developer
film handling
should be limited ti 2 1/2 min under safelight
manual processing requires
processing tank, stirring paddles, thermometer, film hangers, drying racks, drip pans, timer
