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139 Cards in this Set

  • Front
  • Back
types of intraoral radiographs
periapical
bitewing
occlusal
how many pas is used in FX?
18-24 PAs but at OUCOD 20
What sould be seen with correct periapical radiograph?
OUTLINE, POSITION, MESIODISTAL EXTENT, SURROUNDING STRUCTURES, FULL LENGTH OF TOOTH, AND 2-4 MM OF NORMAL BONE SURROUNDING IT

INTERPROXIMAL CONTACTS SHOULD BE OPEN
WHAT DOES BITEWING RADIOGRAPHS RECORD?
OUTLINE, POSITION, MESIODISTAL EXTENT, CORONAL PART OF TOOTH AND BONE OF BOTH ARCHES
WHAT ARE INDICATIONS OF BITEINGS?
EVAL OF INTERPROXIMAL TOOTH SURFACES

EVAL OF INTERPROXIMAL BONE
CENTRAL RAY
MOST CENTRAL PORTION OF XRAYS COMING OUT OF BID
VERTICAL BEAM ANGULATION
UP AND DOWN MOTION OF TUBE IN RELATION TO OCCLUSAL PLANE CAN BE + OR -.

+ IS ABOVE 0 (OCCLUSAL PLANE) AND - IS BELOW
HORIZONTAL BEAM ANGULATION
MOTION OF TUBE AROUND PTS HEAD IN RELATION TO MIDSAGITTAL PLANE
wHAT CAUSES CLOSED CONTACTS?
WRONG HORIZONTAL ANGULATION

central ray in center
WHAT DOES XCP HAVE FOR ORIENTATION?
ANTERIOR AND POSTERIOR BITE BLOCK
XCP INSTRUMENTS
EXTENSION CONE PARALLELING

EXTERNAL GUIDE USED TO POSITION THE XRAY BEAM VERTICALLY AND HORIZONTALLY TO THE FILM

ESTABLISHED A POINT OF ENTRY FOR THE BEAM
WHAT DOES XCP CONSIST OF?
ANTERIOR AND POSTERIOR BITE BLOCKS

INDICATOR ROD

AIMING RING (this allows lining up of the BID)
describe disposable bite blocks/stabes
size 0,1,2 films

anterior and posterior exposures

front section breakable for posterior and pedo exposure
advantages of bitewing loops and adhesive tabs
ready to use

made of heavy duty paper board

adjustable to bite
describe snap-a-ray film holder
sturdy molded plastic

can be autoclaved

elminates manual retention of film pkt

for anterior and posterior xrays

used esp. for endo xrays
what allows us to determine if we have the correct vertical and horizontal angulation?
ring and rod
is dot on film toward or away from xray and object?
for periapical xrays the dot is toward the area of interest and the xray beam

for bitewings the dot is toward the lower edge of the film
advantages of film holders
facilitates retention and film placement

relates film to beam indicating device

collimates beam

reduces dose to pt
types of BID
long round open

long rectangular open

short round open
advantages of XCP device
prevents BID or cone cuts

aiming ring is compatible with rectangular and round BID

indicator arm guides BID for proper alignment

reduce distortion

can be autoclaved
4 basic principles of intraoral radiography
1. pt head position

2. location of long axes of teeth

3. xray beam angulation

4. point of entry of xray
Pt head position
pt should be upright

mid sag plane perpendicular tothe floor

occlusal plane or ala tragus line should be parallel to the floor
ala tragus line
parallels tips of maxillary teeth from canine to third molar
long axis of maxilla teeth
tilted facially
descibe long axis of teeth in the mandible
ant teeth are tilted facially

premolars are vertical

molars are inclined lingually
what is wrong if in xray teeth appear shortened or cramped in superior-inferior diminsion?
BID too hi and too far up (over angulation) towards the head so you need to brind the BID down to correct this
What is wrong w/xray if teeth appear elongated in superior-inferior dimension?
BID is too lo (under angulation) which causes elongation of teeth. operator must bring BID up a bit to correct
how does under angulation appear?
elongation of teeth

apices cut off

no periapical bone seen
how does over angulation appear in xray?
foreshortening of teeth

crowns cut off

too much periapical is seen
describe horizontal beam placement to get open contacts
CR must be parallel to interproximal space to get open contacts if CR is not parallel to interproximal space, you get operlaps
2 intraoral PA xray tecniques
paralleling

bisecting angle
advantages of paralleling tecnique for taking PA xrays
better anatomical detail

minimizes undesirable unsharpness,magnification, and shape distortion
Rules for paralleling technique
1.film parallel to long axes of tooth

2.CR perpendicular to long axes of tooth and film plane
paralleling tecnique procedure
place film in holder (dot in slot)

position film to cover area of interest in mouth

position film plane parallel to teeth

vertical angulation of BID (must be vertically parallel to indicator rod)

CR perpendicular to long axes of teeth

Center xray beam
bisecting angle tecnique for taking PAs
angle that is formaed by plane of tooth and plane of film is bisected and the central ray is directed through the paex of the tooth perpendiular to the bisecting line
vertical angulation tecnique with bisecting tecnique
CR through center of filed

perpendicular to bisecting line formed between film and long axes of teeth
errors seen with wrong vertical angulation
elongation

foreshadowing

angle varies w/each view
horizontal angulation
CR perpendicualr to facial surface of teeth in region
main error seen with wrong horizontal angulation
overlapping
poing of entry
center of region

obj should be completely covered
why is long cone recommended?
bc it decreases magnification and unsharpness
BID cut/cone cut
only get a partial image
problem with bisecting angle
hard to master

cant see long axes of teeth so have to estimate

have to imagine bisecting angle

film placement not accuarately seen

causes errors like film bending or imporoper film plalcement
which direction of BW shows more alveolar bone?
vertical BW show more alveolar bone than horizontal BW
With which xray is alveolar bone best shown?
on BW
areas where PAs are taken for FMX
central lateral incisor

canine region

premolar

molar
how are PAs of max central-lateral incisor region taken?
place size one film vertically in bite block

align central and lateral contact w/center of film

place film in posteror of mouth

pt should be biting of end of block away from film

direct CR to pass through the central-lateral contact
characteristics of ideal PA of max central-lateral incisor region
contact between central-lateral incisor should be open and centered on film

2-4 mm of bone beyond apices

incisal edge of teeth should be a bit above lower edge of film

contact between two centrals should be seen on r and l central lateral films
how are PAs of max canine region taken?
place size 1 film vertically in bite block

align midline of canine w/center of film

place film in posteror of mouth, away from lingual surfaces under tongue

pt should bite on end of block away from film

direct CR through mesial contact of canine
Characteristic of ideal PA of max canine region
canine should be centered on film

mesial contact of canine should be open

2-4 mm of NORMAL bone beyond teeth

incisal edge of teeth should be a bit below edge of film
How are PAs of max premolar region taken?
place size 2 film horizontally in midline of palate parallel to long axis of teeth

anterior border of film shold over premolars and distal contact of canine

CR is directed to pass through contact between 1st and 2nd premolar or 2nd premolar and 1st molar
characteristics of ideal PA of max premolar region
2nd premolar should be centered on film

contact between premolar and distal contact of canine should be seen and open

2-4 mm of NORMAL bone beyond teeth

occlusal plane of teeth a bit above lower edge of film

buccal and lingual cusps should be superimposed
how are PAs of max molar region taken?
place size 2 film horizontally in midline of palate,parallel to long axis of teeth, second molar should be centered on film

posteror border of film should cover maxillary tuberosity and distal part of last molar in mouth

CR is diected to pass through the contact between the 1st and 2nd molar
characteristics of ideal PA of max molar region
2nd molar should be centered on film

contact between molars should be open

max tuberosity should be seen in 3rd molar area

2-4 mm of bone beyond apices

occlusal plane of teeth a tad above lower edge of film

buccal and lingual cusps superimposed
where is film holder in relation to tooth?
film holder must be used to keep film parallel to long axis of tooth
purpose of long BID
increases source film distance to increase magnification and decrease image distortion
Occlusal xrays
cross section of arches to see incisal and occlusal sufaces of teeth

used to see impacted teeth,fractures,and foreign bodies, jaw lestions, and salivary stones
vertical angle of maxillary occlusal xray
Direct central ray at vertical angulation of 60-65
CR of occlual xray mandibular view
direct the central ray at the midline through the floor ofthe mouth approx 3 cm below the chin at right angle to the center of the film
anatomic variations
tori
edentulous ridges
apprehensive pt
tongue size
depth of palate
hi muscle attachments
different exposure time with edentulous ridge
25% less exposure time

do only 14 PA film with size 2 films (1 midline, 2 lateral canine, 2 premolar, 2 molar)

no BW needed
simplest, fastest, and least uncomfortable alternative to intraoral
pano
ways to reduce pain and hypersensitivty so we can take xray on pt
tissue protectors
topical anesthetics
film bending
tranquilizers
edge ease comfort cushions
developed by DH

pt bit hader on film holder

improves pt comfort bc procts soft tissue from film abrasion

reduces no of retakes
managing gagging pt
reduce psychic stimuli
pleasant conversation
anterior films taken first
divert pt attention
premed


Reduce tactile stimuli
mimimal film motion in moth
minimal contact w/mucosa
flm holders/cusion
desensitizers
procedure quick
get help
combine intra/extraoral
what is a good radiograph?
has proper visual characteristics and minimal projection geometry
what does diagnostic quality depend on?
proper visual characteristics
(contrasts and density)

minmial projection geometry
(geometric unsharpness, motion unsharpness, screen unsharpness)

anatomical accuracy

adequate covreage of anatomical area of interest
visual characteristics
density

contrast
density
degree of blackness on the film

depends on amt of radiation; greater the amount of xrays reaching film, greater the density
what is the correct density?
faint outline of soft tissues should be seen along with hard tissues
useful range of film density
0.3 v.lt to 3.0 v.dark

beyond this the film is either too light or too dark
primary factors controlling radiographic density
milliamper seconds mAs
kVp
source film distance
secondary factors controlling radiographic density
dev. conditions
film type
intensifying screens
grids
obj density
how does mAs control density?
blackness varies directly and proportionally w/current and exposure time. the higher the mAs the greater the density
how does kVp control density?
greater the kVp, more speed and more penetration of xray. the more xrays strike the film emulsion and make a greater density
how does source film distance control density?
beam intensity varies inversely to square of source film distance

shorter the distance, the greater the intensity of the beam and the higher the film density
what is the correct density?
faint outline of soft tissues should be seen along with hard tissues
what does doubling the distance do to density?
decreases it by four
useful range of film density
0.3 v.lt to 3.0 v.dark

beyond this the film is either too light or too dark
what does halving the distance do to density?
four times greater density
primary factors controlling radiographic density
milliamper seconds mAs
kVp
source film distance
what does dev time do to density?
underdev produces lo density image (either due to depletion of dev sln or temp is too cold for processing)

over dev can make hi density (fog)
what is the correct density?
faint outline of soft tissues should be seen along with hard tissues
secondary factors controlling radiographic density
dev. conditions
film type
intensifying screens
grids
obj density
how does film type affect density?
hi spped film require less mAs to make density change compard w/slower film
useful range of film density
0.3 v.lt to 3.0 v.dark

beyond this the film is either too light or too dark
primary factors controlling radiographic density
milliamper seconds mAs
kVp
source film distance
what mAs does hi speed intensifying screnns require to maintain density?
less mAs
what mAs does grip require to maintain constant density?
more mAs
secondary factors controlling radiographic density
dev. conditions
film type
intensifying screens
grids
obj density
how does mAs control density?
blackness varies directly and proportionally w/current and exposure time. the higher the mAs the greater the density
how does mAs control density?
blackness varies directly and proportionally w/current and exposure time. the higher the mAs the greater the density
radiographic contrast
differences in densities on film
how does kVp control density?
greater the kVp, more speed and more penetration of xray. the more xrays strike the film emulsion and make a greater density
what primarilily affects radiographic contrast?
primarily affected by kVp
how does kVp control density?
greater the kVp, more speed and more penetration of xray. the more xrays strike the film emulsion and make a greater density
how does source film distance control density?
beam intensity varies inversely to square of source film distance

shorter the distance, the greater the intensity of the beam and the higher the film density
what does doubling the distance do to density?
decreases it by four
how does source film distance control density?
beam intensity varies inversely to square of source film distance

shorter the distance, the greater the intensity of the beam and the higher the film density
what does halving the distance do to density?
four times greater density
what does doubling the distance do to density?
decreases it by four
what does dev time do to density?
underdev produces lo density image (either due to depletion of dev sln or temp is too cold for processing)

over dev can make hi density (fog)
what does halving the distance do to density?
four times greater density
what does dev time do to density?
underdev produces lo density image (either due to depletion of dev sln or temp is too cold for processing)

over dev can make hi density (fog)
how does film type affect density?
hi spped film require less mAs to make density change compard w/slower film
what mAs does hi speed intensifying screnns require to maintain density?
less mAs
how does film type affect density?
hi spped film require less mAs to make density change compard w/slower film
what mAs does grip require to maintain constant density?
more mAs
what mAs does hi speed intensifying screnns require to maintain density?
less mAs
radiographic contrast
differences in densities on film
what mAs does grip require to maintain constant density?
more mAs
what primarilily affects radiographic contrast?
primarily affected by kVp
radiographic contrast
differences in densities on film
what primarilily affects radiographic contrast?
primarily affected by kVp
long scale contrast
lo contrast

higher kVp (80-90) more penetrating xrays so density differences are small and contrast is low. there are few blacks and whites and many shades of gray
how do you go from long scale to short scale contrast?
decrease kVp
short scale contrast
hi contrast

lower kVp (60-65) less penetrating xrays. density differences are large. hi contrast

more blacks and whites with few shades of gray
optimal contrast of PAs
should show lo contrast to see osseous changes
optimal contrast of BW
should have hi contrast to see dental caries detection
if kVp increases, what must be decreased to maintain density?
if kVp is increased, mAs or exposure time must be decreased to maintain previous density
what does kVp affect
speed of xrays and number of xrays produced
will changing mAs only cause a change in contrast
no. mainly just kVp causes change in contrast
what does image sharpness measure?
how well a boundary between two areas differeing radiodensity is revealed
what can image unsharpness be due to?
geometric unsharpness

motion unsharpness

screen unsharpness
geometric unsharpness
diffustion of detail
penumbra
unsharp margin surrounding the image. also known as edge gradient. unsharp margin or blurred zone on image is seen as xrays orinate from focal spot and travel in straight lines, their projectons of feature of an object do not occur at exactly the same location on the film
3 reasons image unsharpness, distortion, and magnification occurs
1.xrays originate from an area rather than a point

2.xrays travel in diverging straight lines as they radiate from the source

3.human structures have depth,width,and lenghth
5 rules for accurate image formation to minimize loss of image clarity
1.effective focal spot should be as small as possible

2.distance between focal spot and obj should be as long as possible

3.film should be as close to obj as possible

4.long axis of obj should be parallel to film

5.central ray should be perpendicualr to film to record structures in true spatial relationships
what happens to penumbra and image definition as focal spot gets smaller?
smaller the focal spot size, the smaller the nenumbra and the higher the image definition
when are lingual cusps sharper?
when closer to film
how does obj film distance affect sharpness?
longer the obj-film distance, the greateer the unsharpness

objects closer to the film have a sharper image
how can radiographic image magnification can be decreased?
by using longer source-oject distance and shorter object-film distance
how can shape distortion be minimized?
by using radiographic intraoral paralleling tecnique
what problem arises w/bisecting angle tecnique?
inherent shape distortion
when does an xray have anatomic accuracy?
when it has....
proximal contacts open

CEJ

buccal and lingual cusps superimposed

bccal and lingual portion of alveolar crest superimposed

no superimpostion of zygomatic arch over roots of max teeth
what causes superimpostion of zygomatic arches over roots of max teeth?
over angulation
film coverage
area of interest shown in xray
PA film coverage
2-4 mm of normal bone surrounding apices of teeth
what does adequate film coverage depend on?
proper alignment of film and radiation beam to area of interest

proper selectoin of film type

proper selection of film-projection tecnique