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38 ch review

whole chapter for test reveiw

Radiographs enable the dentist to see conditions that are not visible in the oral cavity and to identify many conditions that might otherwise remain undetected
many dental diseases and conditions have no clinical signs or sympstoms and are typically discovered only through the use of dental radiographs
____ has teh ability to cause damage to all types of living tissues radiation
Any exposure to radiation no matter how small has the potential to cause harmful biologic changs in the operator and the patient
who discovered the x-ray on Nov 8 1985 Wilhelm Conrad Roentgen
what does the x in x-ray stand for represents the unknown
what represented the first radiograph of the human body Roentgen's wife's hand
what were x-rays first referred to as, and what was radiology referred to as, and what were radiographs known as roentgen rays and roentgenology, and roentgenographs
who made the first dental radiograph Otto Walkhoff
how long did the first dental radiograph take to expose 25 minutes
who is credited with the first practical use of radiographs in dentistry C. Edmund Kells
C. Edmund Kells dedication to the development of dental radiography eventually cost him his fingers, later his hand, then his arm and after enduring much pain and being faced with the prospect of becoming a burden to his family he committed suicide in 1928.
dense core of the atom that is compromised of particles known as protons and neutrons. nucleus
___ carry positive electrical charges protons
___ carry no charge neutrons
Dental x-rays _____ make atoms radioactive can not
patients _____ give off x-rays after the x-ray machine stops producing x-rays do not
tiny negatively charged particles that have very little mass electrons
electrons remain stable in their orbit around the necleus until radiograph photons collide with them
x-rays belong to a group classified as electromagnetic radiation
what things are also classified as electromagnetic radiation visible light, radar, radio, and television waves
Electromagnetic radiation is made up of photons that travel through space at the speed of light in a straight line with a wavelike motion
the ______ the wavelength of the x-ray the _____ is its energy shorter, greater
which wavelengths are especially usefull in dentistry shorter
what are the 3 primary components that x-ray machines all have tubehead, extension arm and control panel
parts of the tubehead xray tube, metal housing, anode, insulating oil, unleaded glass window of xray tube, lead collimator,PID, aluminum discs, tubehead seal, filament circut, cathode
metal body that contains the x-ray tube tube head housing
fills the housing and surrounds the x-ray tube, this prevents overheating by absorbign the heat created by the production of x-rays insulating oil
made of leaded class or aluminum keeps the oil in the tubehead and acts as a filter to the x-ray beam tubehead seal
where x-rays are produced x-ray tube
alters the voltage of incoming electric current transformer
metal disk with a small opening in the center it is located inside the PID in the path of the x-ray beam, it limits the size of the x-ray beam lead collimator
when the size and shape of the beam are changed to a rectangle only slightly larger than the film the amount of tissue exposed to radiation can be reduced by more than 1/2
The PID is the open ended lead lined cylinder that extends from the opening of the metal housing
the x-ray tube is the ____ of the x-ray generating system. heart
the ____ or ____ electrode, consists of a tungsten filament in a focusing cup made of molybdenum. the purpose of this is to supply the electrons necessary to generate x-rays cathode, negative
the ___ the filament becomes ,the ___ electrons are produced hotter, more
the focusing cup keeps: electrons suspended in an electron cloud at the cathode
the ___ or ___ electrode acts as the target for the electrons, it is composed of a tungsten targetthat is embedded in the larger copper stem anode, positive
the copper around the tungsten target does what conducts the heat away from the target, reducing the wear on the target. It serves as a focal spot and converts the electrons into x-ray photons
what % of the x-rays generated are absorbed by the oil 99%
what # of the x-rays generated exit the tubehead through the opening as a divergent beam toward the patient 1 %
what 2 shapes can the PID be cylindrical or rectangular
which PID shape limits the size of the beam to that of a dental film rectangular
means to move in a side to side motion horizontally
means to move in an up and down motion vertically
what must a dental assistant or patient never do to the tubehead hold it in place during exposure
what is the abreviation for milliamperage mA
what is the abreviation for kilovoltage kV
the milliamperage selector controls what the number of electrons that are procuded
the kilovoltage selector controls what penetrating power of the x-ray beam
dental x-ray machines generally operate at what kVp 70 or 90
characteristics of the x-ray beam are described as the quality , quantity and intesity of the x-ray beam
structures that radiation can easily pass through appear radiolucent ( dark ) on a radiograph
examples of things that will show up radiolucent on a film air spaces, soft tissues, abcesses, tooth decay, and dental pulp
structures that radiation does not easily pass through appear radiopaque ( white or light gray ) on a radiograph
examples of things that will show up radiopaque on a film metal restorations, tooth enamel, dense areas of bone
the range of shades of gray to black to white is called contrast
___kilovoltage produces more penetrating radiographs and ____ radiographic contrast higher, lower
___ is the overall blackness or darkness of a film density
the degree of density is controlled by the ___ seconds milliampere
if the radiograph is not exposed for a suffiecient amount of time or is exposed with a low milliampere setting, the resulting radiograph will not have the correct overall density or will be: light in appearance
other factors that influence the density of the radiograph include: distance from the x-ray tube to the patient, developing time and temperature, and body size of the patient
if the operator lengthens the source-film distance without changing the exposure settings, resulting radiographs will be light or less dense
If the processing time is too long, the radiograph will appear dark
A patient who is very small or thin requires___ radiation than a husky, heavy boned person less
which 3 geometric characteristics affect the quality of the radiograph sharpness, magnification and distortion
___ refers tohow well the radiograph reproduces the fine details or distinct outlines of an object, is sometimes referred to as detail, resolution or definition. sharpness
the sharpness of an image in influenced by what focal spot size, film composition and movement
a machine with a___ focal spot results in a sharper image than a machine with a ___ focal spot size smaller, larger
fast film speeds result in __ ___ detail because of the ___ crystal size less sharp, large
any movement of the patient or the film, no matter how slight will __________ of the image degrade the sharpness
___ refers to the disproportionate change in the size of images on radiographs that is caused by excessive or insufficient vertical angulation distortion
______ refers to the proportionate enlargement of a radiographic image magnification
the cumulative effect of radiation exposure can be compard with the cumulative effect from what repeated exposure over the years to the rays of the sun
which organs are considered critical organs skin, thyroid gland, lens of the eye and bone marrow
two sets of systems are used to define the ways in which radiation is measured, the older system is referred to as ____, the newer system is ____ the traditional system or standard system, the metric equivalent known as the susteme internationale
the maximum permimssible dose is defined as the maximum dose equivalent that a body is permitted to receive in a specified period of time
The current MPD for persons occupationally exposed to radiation is 5000 millirem or 5.0 rems/year
for non occupationally exposed persons, the MPD is .1 rem/year
dental personnel should strive for an occupational dose of 0 by adhering to strict radiation protection practices
back ground radiation comes from natural sources such as radioactive materials in the ground and cosmic radiation from space
when dental radiographs are prescribed and properly taken, the benefit of disease detection _____ the risk for biologic damage associated with receiving small doses of radiation far outweighs
when radiographs must be retaken because of poor operator technique the patient is exposed to unnecessary additional radiation
the decision to expose new radiographs must be base on what how recently previous films were taken and the clinical need for additional films
radiographs should never be taken on a "routine basis"
what is the purpose of the aluminum filter to remove the low engery long wavelength, least penetrating x-rays from the beam
what is the collimator used for to restrict the size and shape of the x-ray beam to reduce patient exposure
what is the PID position indicator device, used to direct the x-ray beam, has a round or rectangular shape
the PID is available in which two lengths, why is it available in two lengths 8 inch and 16 inch, a long PID is more effective in reducing exposure to the patient than a short one because it causes less divergence of the beam
what must you not do to the lead apron when storing fold
what is the main factor in determining film speed the size of the silver bromide crystals
in reference to film speed the _____the crystals the ____ the film larger, faster
a fast film requres _________ to produce a quality radiograph less exposure
_____ film is the most effective method of reducing a patients exposure to fast, x-radiation
film holding devices are used for what purposes to keep the patients hands and fingers from being exposed to x-radiation, holds the film in a stable position and assists the operator in properly positioning the film and PID
a setting of ______ keeps patient exposure to a minimum 70 to 90 kVp
in reference to taking x-rays on pregnant patients the ADA and FDA state that dental radiograpic procedures "do not need to be altered because of pregnancy"
what are the 3 types of monitoring devices used to determine the amount of radiation exposure to personnel film badge, pocket dosimeter ( pen style ) and thermoluminescent device
the ________ is most commonly used to measure the amount of occupational exposure film badge
Created by: cynthia.fryer