exam 5 (chapters 21,22,23,25,29) Flashcards
(126 cards)
1
Q
this is a radiographic image produced by conventional film?
A
analog image
2
Q
when do you know if a structure is on the lingual?
A
if the structure moves in the same direction as the tubehead
3
Q
when is the SLOB method?
A
when TWO radiographs are taken in a slightly different angle (either horizontal or vertical), the structures shift slightly on the radiographs..
4
Q
what is a sensor?
A
special plate sensitive to xrays that captures the radiographic image.. (latent image on film)
placed in the mouth as you would film even using holding devices
5
Q
rounded projection of temporal bone located anterior to the glenoid fossa
rounded radioapque
A
articular eminence
not seen on intraoral images
6
Q
thin prominence of bone, shaped like a crows beak and is found on the ant. sup. ramus of mandible
triangular radiopacity post. to max. tuberosity region
A
coronoid process
7
Q
what screen emits a blue to violet fluorescent light and must be paired with blue light sensitive film?
A
calcium tungstate
8
Q
bony wall that separates nasal cavity from oral cavity..
horizontal radiopaque band superior to the apices of max. teeth.. may be viewed on intraoral iamges..
A
hard palate
9
Q
air space of pharynx located posterior to the tongue and oral cavity..
vertical radiolucent band superimposed over the ramus of the mandible..
A
glossopharyngeal air space
10
Q
thick, linear prominence of bone that defines the lower border of mandible..
radiopauq band that outlines lower border of mandible.
A
inferior border of mandible
11
Q
aka nasal fossa, pear shaped compartment of bone located superior to maxilla
large radiolucent area superior to max. incisors.. may be viewed on intraoral images
A
nasal cavity
12
Q
moving center rotation?
A
most modern machines fall in this category. the ellipitcal pattern closely matches the arc of the teeth. a continuous image is produced. the horizontal and vertical magnification are relatively constant. the elliptical pattern can be adjusted to fit most people
13
Q
what are some errors that occur with the pano?
A
pt. is too foward in trough, the anterior teeth will be blurred and diminished in width
pt. too far back in trough, the anterior teeth will be blurred and magnified.
pt. head tilted or rotated, teeth closer to film appear smaller or teeth further from film will be magnified
pts. chin tipped too low, exaggerated smile and condyles are upward
pts. chin tipped upward- exaggerated frown, condyles are gone
pt. is slumped- radiopaque superimposed over anterior teeth
14
Q
solid state silicate chip detector that converts light or xray photons into an electrical charge or signal; in digital imaging, this is found in sensor.
A
charged coupled device (ccd)
15
Q
what MUST you do when placing the pt. in panoramic?
A
place properly to put them in the correct line of radiation because the vertical is preset in the tube head and the trough is a set shape, you cannot aim the tube head..
16
Q
newer rare earth screen…
A
phosphors emit green light and must be paired with green sensitive film.. need even less radiation than the blue
17
Q
besides teeth, what does a panoramic image show?
A
alveolar bone, sinuses, TMJ, maxilla and mandible
18
Q
if the film packet is placed close to the lingual surface of the tooth, how will it appear on an xray?
A
the lingual root is supposed to appear more clearly, the buccal root is further away from the film and is supposed to appear less clearly.
19
Q
what does SLOB stand for?
A
same lingual, opposite buccal
20
Q
linear prominence of bone located on the internal surface of the mandible that extends downward and forward from the ramus
radiopaque band
A
internal oblique ridge
21
Q
what are cassettes?
A
hold intensifying screens in close contact with the film protecting all from light exposure..
rigid- 5x7 front and back joined with hinge
flexible-5x6x12 with velcro
22
Q
PSP
A
photo stimuable phosphor
rare earth phosphor (barium europium fluorohalide) coated plates used as sensors
when exposed, psp stores xray energy until stimulated by a laser
separate scanning device is required that read the fluorescent signal and converts it into a digital image
plates are reusable by erasing the image by exposing to bright light
23
Q
what are the 5 typical occlusal radiographs?
A
maxillary topographical (anterior) maxillary topographical (posterior) mandibular topographical (anterior) mandibular topographical (posterior) mandibular cross sectional
24
Q
what is the purpose of an occlusal radiograph?
A
to view large areas of the maxilla and the mandible.. the film is placed between the teeth.
25
what does a panoramic image show?
a broad view of the entire dentition of both maxillary and mandibular teeth on a single film.. 5 or 6x12 film is placed in a cassette and positioned extraorally..
26
how long is exposure time in pano?
usually 15-20 seconds..
27
air space of the pharnyx, located posterior to the nasal cavity..
radiolucent band located superior to the radiopaque shadow of soft palate and uvula
nasopharyngeal air space
28
long pointed, sharp projection of bone that extends downward from the inferior surface of the temporal bone..
long radiopaque spine that extends from temporal bone to anterior mastoid process.
styloid process
| not seen on intraoral images
29
small, hook like projection of bone that extends from the medial pterygoid plate of sphenoid bone, located post. to max tuberosity.
radiopaque hook like
hamulus
30
linear prominence of bone located on the internal surface of the mandible that extends down from the third molar region down and forward toward apical area of premolars..
radioapque band
mylohyoid ridge
31
what are grids?
a device used yo reduce the amount of scatter radiation that reaches an extraoral film during exposure..
increases radiation dose double, so it should only be used when improved image quality and high contrast are ness.
32
what size receptors are used for adult and child pt..
size 4 adult
size 2 child
33
paired cavities or compartments of bone located within the maxilla, superior rto the max. post. teeth
paired radiolucent areas superior to the apices of max. premolar and molars... floor of max. sinus is composed of dense cortical bone that appears as a radiopaque line,
max. sinus and floor of max. sinus
34
opening or hole in bone located at the midline of the ant. portion of hard palate directly behind max. centrals..aka nasopalitine foramen
round, small, ovid, radiolucency betwwen roots of max. centrals
incisive foramen
35
How does the xray tube head work in panoramic radiography?
generates electrons to generate xrays. the fixed vertical position is usually around 8 degrees or pointing slightly upward. the PID is collimated with a lead diaphgram the shape of a narrow slit opening. the tube head rotates behind the pt. and the xray beam strikes the back of the head and neck.
36
aka mandibular notch.. curved depression located between the mandibular condyle and cornoid processs of mandible..
radiopaque curved depression
sigmoid notch
37
how to capture disto-oblique PA
| s..
shift tubeheadand PID to obtain xray when it may be nearly impossible..
38
what is definitive evaluation of localization based on?
shadow casting principles that is an object positioned father away from the film will be magnified and less clearly imaged..
39
scooped out depressed area of bone located on the external surface of the anterior mandible above the mental ridge in the mand. incisor region
radiolucent area above mental ridge
mental fossa
40
intensifying screens of panoramic radiography..
transfers xray energy into visible light
allows for much less radiation since intensified
smooth plastic almost looks like cardboard
coated with minute fluorescent crystals called phosphors
when exposed to xrays phosphors fluoresce and emit blue or green light
41
thin, wing shaped bony extension of sphenoid bone located distal to the max. tuberosity region
radioapque projection of bone
lateral pterygoid plate
| not seen on intraoral images
42
angle formed where the horizontal lower edge of the body meets the perpendicular post. edge of ramus..
radiopaque, where the ramus joins the body of mand.
angle of mandible
43
blue sensitive films..
must be paired with blue light screens, this is a conventional tungstate screen where the phosphors emit blue light
44
vertical angulation used for maxillary lateral occlusal..
+60
45
a hole, or opening in the temporal bone located superior and anterior to the mastoid process
round or ovid radiolucent anterior and superior to mastoid process
external auditory meatus
| not seen on intraoral images
46
what is the weidth of the trough and the distance from the rotational center controlled by?
speed of the moving cassette controlled by manufacturer
47
what is the rotation center in panoramic radiography?
the pivital point or axis which the tube head and the cassette rotate is the functional focus of the projection.
the type of machine and rotation will cause different types of movement of the process
48
short for picture element, discrete units of information that together form the image..
pixel
49
what are cross sectional radiographs?
used to see tori, impactions and malpositioned teeth.. it can also show calcifications in soft tissues. (salivary gland or calcifying cysts)
50
tiny hole or opening in bone located on the internal surface of the mandible near the midline..
small radiolucent dot located inferior to the apices of the mand. incisors
lingal foramen
51
marked prominence of bone located posterior and inferior to the TMJ
appears as a large round radiopacity
mastoid process
| not seen on intraoral images
52
formed by positioning pts lips..areas of teeth no covered by lips are radiolucent, areas of teeth covered by lips are radiopaque
lipline
53
veertical bony wall or partition that divides nasal cavity into R and L sides..
vertical radiopaque partition that divides the nasal cavity.. may be viewed on intraoral images..
nasal septum
54
linear prominence of cortical bone located on the external surface of the ant. portion of the mandible that extends from the premolar region to the midline..
thick radiopaque band
mental ridge
55
right angle method of localization
one periapical receptor is exposed using the proper tech. and angulation to show the position of the object superior inferior and anterior posterior relationships.. next, an occlusal receptor is exposed directing the central ray at a right angle, or 90 degree (perpendicular) to the receptor.. the occulusal image shows the buccal lingual and anterior posterior relationships..after the two xrays have been exposed, the iamges are compared to locate the object..
this is not acceptable in endodontic procedures, only effective if looking for a foreign body
56
vertical angulation used for mand. topographical
-55
57
tube shift method is also known as...
buccal object rule, or SLOB
most versatile and most often used..
58
hole or opening in bone inferior border of the orbit
round, ovid, radiolucency
may be superimposed by max. sinus and cannot be seen on intraoral images
infraorbital foramen
59
panoramic cassette holder..
can be flat or a drum, rotates in front of the pt. and rotates or moves to the side to advance the film into the xray beam as the tube head rotates
60
what is bit depth image?
number of possible gray scale combinations for each pixel
| 8 bit depth image has gray scale combination of 2^8, which equals 256 shades of gray
61
horse-shoe shaped bone that lies below the mandible, between chin and thyroid cartliage..
appears as floating or curved radiopacity below the inferior border of body, may not be visible at alll..
hyoid bone
62
submentovertex radiograph (base projection)
used to show the base of the skull, the position and orientation of the condyles, the sphenoid sinus and fractures of the zygomatic arch.. 8x10 film. the head is extended backward until the top of the head touched the cassette. the nose is up with the midsaggital plane perpendicular to the floor. the frankfort plane is to be vertical to the floor and parallel to the film..
central beam is perpendicular to the film from below the mandible thru the center of the head.
63
form a muscular curtain that separates the oral cavity from the nasal cavity.. appear as a faint diagonal radiopauqe area that projects psot. and inf. from max. tuberosity region,,
soft palate and uvula
64
what are some advantages of a panoramic image?
greater areas of diagnositc qualities with less radiation than a full mouth series
easier for pt to see and understand
less discomfort
less retakes
better time management
65
cartliage within a thin covering of connectivbe tissue and skin.. radiopaque shadow that projects anteriorly and infer. from mastoid process..
ear
66
what means to measure the head? and what device is used..
cephalometric
a cephalometer is a device used to standardize the placement of the head during exposure for a series of identically angled exposures..
67
what are topographical radiographs?
they are used to view the palate and anterior teeth of maxilla or mandible. (size 4 film)
68
what is a triple rotational center?
three centers of rotation are used but the sight of the xray beam is so efficient that a continuous image results on the film.
69
small, tongue shaped projection of bone seen adj. to mand. foramen
radiopacity anterior to mand. foramen
lingula
70
aids in diagnosing ankylyosis (stiffening) of the TMJ caused by fibrous or bony union via malignancies, fractures, and arthritis
a series of radiographs both open and closed mouth is essential.. has largely been replaced with a tomography of the TMJ, a moving radiograph like a panorex only with TMJ as center.
8x10 film positioned against ear and centered over the ear with head upright
central beam is directed toward the center of film with at least a 25 degree vertical angulation with point of entry 2 1/2 inches higher and slighlty in front of the ear.. the beam comes from the opposite side of the head and so must pass thru bone
transcranial radiograph (TMJ projection)
71
opening oe hole in the bone located on the external surface of the mandible in the region of the mand. premolars
small, ovid, radiolucency located in apical region of premolars..
mental foramen
72
bony cavity that contains the eyeball
radiolucent compartment with radiopaque borders located superior to the max. sinuses
not seen on intraoral images
orbit
73
bony projection of maxilla that articulates with the zygoma or cheek bone..
j or u shaped radioapcity located superior ti max. first molar region..
zygomatic process of maxilla
74
how does panoramic tomography work?
the tube head rotates behind the patients head and the cassette moves in front in concert with each other..they are always opposite to each other to create a perpendicular angle for the xray beam to film
75
line pair?
greatest number of paired lines visible in 1 mm of image
increasing resolution increases sharpness
76
what type of light emits green light when energized by xrays and must be paired with green sensitive film?
rare earth screens
77
tiny bumps of bone located on the lingual aspect of the mandilbe
ring shaped radiopaque surrounding lingual foramen..
genial tubercles
78
what is spatial resolution?
discernable separation of closely adjacent image details
determined by the number and size of pixels
increasing pixels increases quality
79
before exposing a maxillary occlusal receptor, how is the pts. head positioned?
max. arch parallel to the floor
80
moveable muscular organ attached to the floor of the mouth, appears as a faint dome shaped radiopaque area superimposed over max. post. teeth
tongue
81
three types of digital sensors..
CCD
CMOS
PSP
82
narrow space that separates the lateral pterygoid plate
radiolucent area between lateral pterygoid plate and maxilla, has the shape of an elongated tear drop that is outlined anteriorly by the posterior border of max. sinus
pterygomaxillary fissure
| not seen on intraoral images
83
rounded projection of bone extending from posterior superior border of ramus of mandible..this rests in the glemoid fossa of temporal bone
bony, rounded, radiopaque
mandibular condyle
84
posterioranterior cephalometric radiographs aka PA projection shows entire skull in a posterioranterior plane (back to front)
the purpose is to examine facial growth and deviations, disease trauma, etc.. the right and left side are not superimposed so more detail can be seen 8x10 film pt. faces cassette
central beam is perpendicular to the film toward the occipital protuberancee (bone near base of skull)
85
what are the two types of occlusal radiographs?
topographical and cross sectional
86
air space between palate and tongue
horizontal well defined radiolucent band located superior to apices of max. teeth
palatoglossal air space
87
ccd-charge coupled device
most widely used
solid state detector made up of grids of transistor elements that convert xrays to electrons
each elemetn represent 1 pixel
640x480 indiv. pixels is size
88
intensifying screens reduce radiation but also reduce sharpness..how?
size of crystals (larger crystals, less radiation)
thickness of emulsion (thicker emulsion, faster speed, less radiation,less sharp)
type of phosphor used (rare earth produce latent image with less radiation)
89
lateral jaw radiograph aka mandibular oblique lateral projection
```
most commonly taken
can be taken with conv. dental office machine
largely replaced with pano's
greater detail
examine posterior region of mandible
great for children and small mouths
see fractures and swelling
```
90
vertical angulation used for mand. cross sectional
90
91
for digital imaging, what is it best for the machine?
low KV (70 or kess) and low mA (5 mA or less) and have DC current
92
what is tomography?
imaging technique that allows the structures located within a selected plane of tissue while blurring the structures outside of the selected plane..
it utilizies a narrow beam of xrays to image a curved layer or slice of tissue
93
tubelike passageway thru bone that travels length of mandbile.. extends from mandibular foramen to mental foramen and houses inferior alveolar nerve and blood vessels..
radiolucent band outlined by two radiopaque lines
mandibular canal
94
rounded prominence of bone that extends posterior to the third molar region
radiopaque buldge distal to the third molar region
max. tuberosity
95
concave or depressed area of temporal bone, the mandibular condyle rests here..
appears as a radiopacity superior to the condyle..
glenoid fossa
| not seen on intraoral images
96
what is a focal trough?
3d curved zone in which structures are clearly demonstrated on a panoramic image.. used to determine where the dental arches are to be positioned.
97
lateral cephalometric radiograph
either lateral skull or frontal projection(posterioranterior)
purpose is to evaluate growth and development, trauma, pathology and abnormalities. 8x10 film is used.. the left side of the face is against the cassette with ear rods to stabilizie the head.. the central beam is directed towards ear opening.
98
disadvantages of panoramic image
less detail, distortion
ghost images (mirror images)
not all pts. fit into focal trough
increased overlapping of interproximal contacts espc. premolars
labillary and lingually teeth are tilted
superimposition of the spine
cannot depict early bone loss
99
cheek bone, articulates with zygomatic process of maxilla..
diffuse radiopaque band that exteends from zyg. process of maxilla..
zygoma
100
what is the purpose of extraoral radiographs?
to examine large areas of the jaw or skull
study growth and dvelopment
detect fractures and evaluate trauma
detect pathologic lesions/diseases
detect and evaluate impacted teeth
evaluate TMJ
substituted for intraoral when pt. has small mouth
101
which plane's focus is at the target in the tube head?
vertical
102
linear prominnce of bone located on the external surface of the mandible that extends down and forward from the ramus..
dense radiopauqe band from ramus to the the molar region
external obl. ridge
103
waters radiograph (sinus projection)
similiar to post.ant. except center of interest is focused on middle 1/3 of face..
purpose is to evauluate max. frontal and ethmoid sinus areas. 8x10 film placed vertical with pt. facing cassette and head tilited slightly back..
central beam perpendicular thru occipital protuberance with target film distance a minimum of 36 inches.
104
what is the vertical angluation used for maxillary topographical oclussal projection?
+65
105
what are some of the purposes of occlusal radiographs?
locate retained roots or extracted teeth
locate supernumerary teeth, impacts, or unereupted
evaluate disease and lesions(cysts and tumors)
locate foreign bodies
locate salivary stones (sialoliths) in submand. gland
evaluate fracturs of bone
evaluate size and shape of tori
can be used for pts. with small mouths
evaluation of sinus borders
evaluation of cleft palate
106
CMOS
complementary metal oxide semiconductor
solid state circuitry
pixels can be smaller and chips more durable less expensive
less computer power, connect USB
does nt require internal computer circuit card
schick technologies and kodak rvg 6000
107
this is the merging of 2 images digitally to show changes that occur over time.. the "like" portions cancel each other out and clearly images and the differences...
digital subtraction
108
reverse towne radiograph (open mouth projection)
used to examine fractures of the condylar neck of mandible..8x10 film placed vertically with pt. forehead on the cassette with mouth open and head tipped down until chin touches chest.
central beam is perpendicular thru the occipital protuberance at a target film minimum of 36 inches
109
sharp, bony projection of maxilla located ant.inf. portion of nasal cavity..
v shaped radiopaque area located at the intersection of the floor of nasal cavity and nasal septum.. may be viewed on intraoral images.
anterior nasal spine
110
what lessens the area exposed to radiation to the area wanted and depicted?
the xray beam is emitted from a narrow vertical slit in the tubehead and is constricted to form a narrow band of radiation in the shape of a trough.
111
how is the cassette in the lateral jaw imaging?
cassetee is flat against cheek and cenetered over mand. 1st molar area.. the front edge of the cassette should protrude slightly beyond the tip of nose and chin.. pt. may help hold by keeping thumb on rim.. head tilted 10-20 degrees toward side to be examined and chin protruded
central beam directed to 1st molars
112
what is a double center rotation?
the tube head and cassette rotate to the midline then the radiation stops until the pt. is shifted then the radiation resumes along with continuation.. a plit image results with a blank space at the mid line..
113
when do you know if a structure is on the buccal?
if the structure moves in the opposite direction of the tube shift..
114
this method is obtaining a digital image, in which a sensor is scanned following exposure to x-radiation and then converted into a digital form that can be viewed on a computer monitor?
indirect
these are copies of original, clarity is lost..
115
where is the screen film placed?
between intensifying screen inside cassette either rigid or flexible
116
round or ovid hole in bone on the lingual aspect of ramus of mandilbe
round, ovid, radiolucency cenetered within ramus.. not seen on intraoral images
mandibular foramen
117
this is AKA filmless imaging, it is not an actual picture but a computers representation of the image from the computers programming?
digital imaging
118
how is the width of the trough determined?
by the distance from the functional center of rotation to the structures being radiographed
119
what are the intensifying screens in extraoral radiography?
transfers xray energy into visible light which exposures the screen film
intensifies the effect of the xrays on the film
allows for reduced radiation
works in pairs
smooth cardboard or plastic sheets in appearance but are coated with fluorescent crystals mixed into a binding medium called phosphors
(causes latent image to be formed)
120
direct digital imaging..
used to replace the traditional film.. uses special sensors and a computer..
the goal is to produce high quality diagnostic images thru pixels, sptial resolution and gray scale..
it is used to detect and classify oral disease and lesions, to detect trauma, evaluate growth and development and working films used in endo or surgery
121
what does term occlusal refer to?
chewing surfaces..
122
how does the panoramic radiograph depict a well defined image of a curved layer of tissue?
the radiation beam passes vertically through the patient toward the cassette and through another vertical slit in the cassette holder to expose the film as it rotates..
either a hard or soft cassette holds film
123
gray scale..
very much like contrast in an image
it is defined as the number of shades of gray in an image. digital claims 65,500 gray levels but monitors can only display 256 gray levels
0-255 zero being pure black and 255 pure white
124
what three facial landmarks are important to position in pano. radiography?
mid-saggital plane- immaginary line divides the pt. into a right and left halves down the center of the nose assuming the pt. is perpendicular to the floor
ala tragus line- imag. line from the ala of the nose(side of nose) thru the tragus (front of the ear)
frankfort plane- imag. line from the orbital ridge (under eyes) to the acoustic meatus (ear opening).. when positioned correctly, this line is parallel to floor
125
what is a screen film?
used for extraoral exposures, sensitive to lightemitted by intensifying screens. minimizes xray exposure necessary to produce a diagnostic image
126
AKA nasoplatine canal
passageway thru bone that extends from superior foramina of incisvie canal to the incisive foramen
tubelike radiolucent area with radiopaque borders.. located between max. central
incisive canal
