1.
A dental assistant may expose radiographs
Correct Answer
C. If it is permissible in the state he or she is employed
Explanation
A dental assistant may expose radiographs if it is permissible in the state he or she is employed. Different states have different regulations regarding the tasks that dental assistants are allowed to perform, including exposing radiographs. Therefore, it is important for dental assistants to be aware of and follow the regulations of the state they are employed in.
2.
The most sensitive cells to ionizing radiation are
Correct Answer
D. Reproductive cells
Explanation
Reproductive cells, such as sperm and eggs, are the most sensitive to ionizing radiation because they undergo rapid division and have a high rate of cell turnover. Ionizing radiation can damage the DNA in these cells, leading to mutations and potentially causing infertility or genetic disorders in offspring. This sensitivity is due to the fact that reproductive cells are responsible for passing on genetic material to future generations, making them more vulnerable to the harmful effects of radiation.
3.
The best type of xray to penetrate body tissue is
Correct Answer
B. Hard rays, short wavelengths
Explanation
X-rays are a form of electromagnetic radiation that can penetrate body tissues. The best type of X-ray to penetrate body tissue is hard rays with short wavelengths. Hard rays have higher energy and shorter wavelengths, allowing them to pass through body tissues more easily. Soft rays with long wavelengths have lower energy and are less effective at penetrating body tissues. Therefore, hard rays with short wavelengths are the most suitable for imaging and diagnosing conditions within the body.
4.
Xrays are made up of
Correct Answer
C. pHotons
Explanation
X-rays are a form of electromagnetic radiation, which consists of particles called photons. Photons have no mass or charge, and they travel at the speed of light. When high-energy electrons collide with a metal target, they release photons with a very short wavelength, which are known as X-rays. Therefore, the correct answer is photons.
5.
The cathode is a filament composed of
Correct Answer
A. Tungsten
Explanation
The cathode is a filament composed of tungsten. Tungsten is commonly used as the filament material in incandescent light bulbs and electron tubes because it has a high melting point and is a good conductor of electricity. Its high melting point allows it to withstand the high temperatures generated when an electric current passes through it, while its conductivity allows it to efficiently emit electrons when heated, enabling the cathode to function properly.
6.
Milliamperage controls
Correct Answer
D. Heating of the cathode
Explanation
The milliamperage controls the heating of the cathode. When the milliamperage is increased, more electrons are emitted from the cathode, resulting in increased heating of the cathode. This heating is necessary for the cathode to emit electrons and initiate the flow of current in the X-ray tube.
7.
Collimation of the primary beam
Correct Answer
B. Restricts the size and shape of the xray beam
Explanation
The correct answer is "restricts the size and shape of the x-ray beam." Collimation refers to the process of limiting the size and shape of the x-ray beam to the area of interest. By restricting the size and shape of the beam, unnecessary radiation exposure to the patient and surrounding areas is minimized. This helps to improve image quality by reducing scatter radiation and improving contrast. Additionally, collimation helps to ensure that only the desired anatomy is included in the final radiograph, making it easier for the radiologist to interpret the image.
8.
The lead diaphragm determines the size and shape of the
Correct Answer
C. Xray beam
Explanation
The lead diaphragm determines the size and shape of the x-ray beam. The diaphragm is used to limit the area that the x-ray beam covers, allowing for more precise targeting of the desired area. By adjusting the lead diaphragm, the size and shape of the x-ray beam can be controlled, which is important for obtaining clear and accurate x-ray images.
9.
The portion of the target that is struck by electrons is called the
Correct Answer
A. Focal spot
Explanation
The correct answer is focal spot. The focal spot refers to the specific area on the target that is struck by electrons in imaging systems such as X-ray machines. This spot is responsible for producing the X-ray photons that are used for imaging. The size and shape of the focal spot can affect the resolution and quality of the resulting image.
10.
Proper collimation for the film size and target-film distance will
Correct Answer
D. Decrease radiation recieved by the patient
Explanation
Proper collimation for the film size and target-film distance will decrease the radiation received by the patient. Collimation refers to the process of restricting the size of the X-ray beam to the area of interest. By properly collimating the X-ray beam, unnecessary radiation exposure to the patient's body can be minimized. This helps to ensure that only the necessary area is exposed to radiation, reducing the overall radiation dose received by the patient.
11.
To increase the penetrating power of an xray beam, the auxiliary must
Correct Answer
A. Increase KvP
Explanation
Increasing the Kilovoltage Peak (KvP) in an x-ray beam increases the penetrating power of the beam. KvP determines the energy of the x-ray photons produced, and higher energy photons can penetrate through denser tissues more effectively. Therefore, increasing KvP allows the x-ray beam to pass through the patient's body more easily, resulting in better image quality and diagnostic accuracy.
12.
The xray at the center of the xray beam is called the
Correct Answer
B. Central ray
Explanation
The x-ray at the center of the x-ray beam is called the central ray. This term refers to the primary x-ray beam that passes through the patient's body and is used to create the diagnostic image. The central ray is typically aligned with the area of interest to ensure accurate imaging and minimize radiation exposure to surrounding tissues. It is an essential component in producing high-quality x-ray images.
13.
The housing of the xray tube is
Correct Answer
D. Glass
Explanation
The housing of the x-ray tube is made of glass because glass is a good insulator and can withstand the high temperatures generated during x-ray production. It also allows for the passage of x-rays while protecting the surrounding environment from radiation. Additionally, glass is transparent, allowing technicians to visually inspect the tube for any damage or malfunction.
14.
Filtration of the xray beam protects the patient by
Correct Answer
B. Eliminating weak wavelength xrays from the xray beam
Explanation
Filtration of the x-ray beam protects the patient by eliminating weak wavelength xrays from the x-ray beam. Weak wavelength xrays have lower energy and are less penetrating, which means they are more likely to be absorbed by the patient's body tissues. By eliminating these weak xrays, the filtration reduces the dose of radiation received by the patient, minimizing the potential harm and increasing the safety of the procedure.
15.
The size of the collimated beam for intraoral radiology measured at the patients skin is
Correct Answer
C. 2.75 - 3.0 inches
Explanation
The correct answer is 2.75 - 3.0 inches. This range represents the size of the collimated beam for intraoral radiology when measured at the patient's skin. It indicates the diameter of the beam that is used to capture the radiographic image inside the patient's mouth. This specific range is commonly used in dental radiography to ensure that the entire area of interest is captured while minimizing unnecessary radiation exposure to surrounding tissues.
16.
Scatter radiation is a type of
Correct Answer
A. Secondary radiation
Explanation
Scatter radiation refers to the radiation that is deflected or scattered in different directions after interacting with an object or surface. It is called secondary radiation because it is produced as a result of the interaction of primary radiation with matter. Primary radiation, on the other hand, refers to the initial radiation that is emitted directly from a source. Stray radiation refers to any radiation that is not part of the intended beam and can include scatter radiation. Filtered radiation refers to radiation that has been selectively attenuated or removed by a filter. Therefore, the correct answer is secondary radiation.
17.
The quality, or penetrating power, of secondary radiation is
Correct Answer
B. Less than that of primary radiation
Explanation
Secondary radiation refers to the radiation that is produced as a result of the interaction between primary radiation and matter. It can be in the form of scattered or secondary X-rays, or other types of radiation. The penetrating power of radiation refers to its ability to pass through matter. Primary radiation, which is the initial radiation emitted from a source, generally has higher energy and therefore greater penetrating power compared to secondary radiation. Therefore, the correct answer is that the quality or penetrating power of secondary radiation is less than that of primary radiation.
18.
The first sign of xray dermatitus is
Correct Answer
B. Erythema
Explanation
Erythema is the correct answer because it refers to redness or inflammation of the skin, which is one of the first signs of x-ray dermatitis. This condition occurs when the skin is exposed to high levels of radiation, leading to skin damage and various symptoms such as redness, swelling, and blistering. Alopecia, dry skin, and pain may also occur as the condition progresses, but erythema is typically the initial symptom.
19.
The time period between the effects of cumulative radiation and visible tissue damage is the
Correct Answer
C. Latent period
Explanation
The latent period refers to the time period between the effects of cumulative radiation and visible tissue damage. During this period, there may not be any immediate symptoms or visible signs of damage. It is called the latent period because the effects of radiation exposure are not immediately apparent and may take some time to manifest. This period can vary depending on the dose of radiation received and the specific tissues or organs affected.
20.
The amount of radiation a person recieves
Correct Answer
C. Is cumulative in the entire body
Explanation
Radiation exposure is cumulative in the entire body, meaning that the effects of radiation build up over time and are not limited to just the skin. This means that even small doses of radiation can have harmful effects on the body if they accumulate over time. It is important to minimize radiation exposure to protect overall health and well-being.
21.
Maximum protection of the patient requires that the xray beam pass through a
Correct Answer
A. Shielded open-ended cone
Explanation
The correct answer is a shielded open-ended cone because it provides maximum protection for the patient. By using a shielded cone, the x-ray beam is directed only towards the specific area of interest, minimizing unnecessary exposure to other parts of the body. The open-ended design allows for better visualization and positioning of the cone, ensuring accurate and precise imaging. The shielding material further reduces scatter radiation, protecting both the patient and the operator. Therefore, a shielded open-ended cone is the most effective option for maximizing patient safety during x-ray procedures.
22.
A technique used to measure the operators exposure to radiation is
Correct Answer
B. For the operator to wear a radiation film badge
Explanation
The correct answer is for the operator to wear a radiation film badge. This is because a radiation film badge is a device worn by operators to measure their exposure to radiation. It contains a film that darkens when exposed to radiation, allowing for the measurement of the amount of radiation the operator has been exposed to. This is a common and effective method used in industries where workers are at risk of radiation exposure, such as nuclear power plants or medical facilities.
23.
Accumulated radiation dosage for those who work with radiation may not exceed
Correct Answer
A. 0.1 rem/week
Explanation
The accumulated radiation dosage for those who work with radiation should not exceed 0.1 rem/week. This limit is set to ensure the safety of individuals who are exposed to radiation regularly. Higher levels of radiation can have harmful effects on the body, including an increased risk of cancer and other health problems. Therefore, it is important to adhere to the recommended limit of 0.1 rem/week to minimize the potential risks associated with radiation exposure.
24.
The operator must avoid all of the following EXCEPT
Correct Answer
D. Natural sunlight
Explanation
The operator must avoid stray radiation, secondary radiation, and the primary beam to ensure safety and accuracy in their work. However, natural sunlight is not a concern in this context as it does not pose any direct risks or interference with the operator's tasks.
25.
To avoid exposure to secondary radiation, the operator should stand
Correct Answer
A. At least 6 feet from xray head
Explanation
To avoid exposure to secondary radiation, the operator should stand at least 6 feet from the x-ray head. This distance ensures that the operator is outside the immediate vicinity of the primary beam, reducing the risk of direct exposure. Standing farther away from the x-ray head also minimizes the chances of exposure to scattered radiation, which can occur when the primary beam interacts with objects or surfaces in the surrounding area. By maintaining a safe distance, the operator can effectively protect themselves from unnecessary radiation exposure.
26.
The most effective way to reduce gonadel exposure from xrays is to
Correct Answer
B. Use a leaded lap apron
Explanation
Using a leaded lap apron is the most effective way to reduce gonadal exposure from x-rays. Lead is a dense material that can effectively block radiation, and by wearing a leaded apron over the lap area, the gonads can be shielded from the harmful effects of radiation. This is particularly important in medical imaging procedures where the pelvis or abdomen is being imaged, as these areas contain the reproductive organs. Increasing kVps or vertical angulation, as well as using ultraspeed film, do not directly address the issue of gonadal exposure and are not as effective as using a leaded apron.
27.
After each use the leaded apron must be
Correct Answer
C. Draped over a support rod unfolded
Explanation
The leaded apron must be draped over a support rod unfolded after each use to ensure its proper storage. This allows the apron to be easily accessible for future use and prevents any creases or folds that could damage the protective lead lining. Additionally, draping the apron over a support rod helps to maintain its shape and prevent any unnecessary wear and tear. Storing the apron in a darkroom or discarding it for infection control purposes would not be appropriate or necessary.
28.
Which characteristics of xrays make them both beneficial and hazardous?
Correct Answer
C. They destroy tissue
Explanation
X-rays are both beneficial and hazardous due to their ability to destroy tissue. On one hand, this characteristic allows them to be used in medical imaging to detect and diagnose various conditions. On the other hand, excessive exposure to x-rays can be harmful as they can damage and destroy healthy tissues, leading to potential health risks such as radiation burns, genetic mutations, and an increased risk of developing cancer. Therefore, while x-rays have significant medical benefits, their destructive nature necessitates careful and controlled usage to minimize potential harm.
29.
The best technique for reducing the radiation exposure to both patient and operator is the use of
Correct Answer
B. Fast film
Explanation
Using fast film is the best technique for reducing radiation exposure to both the patient and the operator. Fast film requires less exposure time to capture an image compared to slower films, which means less radiation is needed. This reduces the overall radiation dose received by the patient and also minimizes the amount of time the operator is exposed to radiation. Fast film is particularly beneficial in situations where quick image acquisition is necessary, such as in emergency cases or when dealing with restless or uncooperative patients.
30.
Film speed is determined by the
Correct Answer
C. Size of the silver bromide crystal
Explanation
The size of the silver bromide crystal determines the film speed. Smaller crystals allow less light to be captured, resulting in a slower film speed, while larger crystals allow more light to be captured, resulting in a faster film speed.
31.
The radiographic film is covered with an emulsion of
Correct Answer
A. Silver bromide crystals
Explanation
The radiographic film is covered with an emulsion of silver bromide crystals. This is because silver bromide is photosensitive and can be exposed to light to capture the image. When the film is exposed to X-rays, the silver bromide crystals react and create a latent image. This image can then be developed and fixed to produce a visible image on the film. Cellulose, silver acetate, and potassium bromide are not commonly used in radiographic films and do not have the same photosensitivity properties as silver bromide.
32.
The raised button on the radiograph aids in
Correct Answer
D. Mounting
Explanation
The raised button on the radiograph aids in mounting. This is because the raised button provides a point of reference for aligning the radiograph correctly in the mounting process. Mounting involves attaching the radiograph securely to a backing board or film mount to ensure it remains in place and can be easily viewed and interpreted. The raised button helps to ensure that the radiograph is positioned accurately and consistently during the mounting process.
33.
The purpose of the lead foil in dental film is to
Correct Answer
B. Reduce film fogging
Explanation
The lead foil in dental film is used to reduce film fogging. Film fogging occurs when stray radiation reaches the film and causes a hazy appearance. The lead foil acts as a barrier, preventing the stray radiation from reaching the film and thus reducing fogging. This ensures that the images produced on the dental film are clear and accurate for diagnosis and treatment planning.
34.
The detection of interproximal carries is best seen by a
Correct Answer
C. Bite-wing film
Explanation
The detection of interproximal caries is best seen by a bite-wing film. Bite-wing films are specifically designed to capture the areas between the teeth, making them ideal for detecting caries in these interproximal spaces. This type of film allows for a clear and detailed view of the tooth surfaces, enabling dentists to identify any signs of decay or cavities that may be present. The other options, such as occlusal film, panorex film, and lateral head plate, are not as effective in visualizing interproximal caries.
35.
Which extraoral film is used to visualize the sinus?
Correct Answer
A. Waters film
Explanation
The Waters film is used to visualize the sinus. The Waters view is an extraoral radiographic technique that provides a lateral view of the maxillary sinuses. It is commonly used in dentistry to assess the sinuses for signs of infection, inflammation, or other abnormalities. This technique involves placing the film under the patient's nose and angling the X-ray beam towards the forehead. This allows for a clear visualization of the maxillary sinuses and helps in diagnosing sinus-related issues.
36.
X-ray films should be kept by the dentist along with other records for
Correct Answer
D. Indefinitely
Explanation
X-ray films should be kept by the dentist indefinitely because they serve as important records for a patient's dental history. These films provide valuable information about the patient's oral health, previous treatments, and any potential issues that may arise in the future. By keeping the X-ray films indefinitely, the dentist can refer back to them as needed for accurate diagnosis, treatment planning, and monitoring the progress of the patient's dental health over time. Additionally, retaining these records can also help in legal and insurance matters if any disputes or claims arise in the future.
37.
If a patient expresses concern about the hazard of radiation, the patient can be assured that
Correct Answer
A. Only those films neccessary for proper diagnosis will be exposed
Explanation
The correct answer is that only those films necessary for proper diagnosis will be exposed. This assurance addresses the patient's concern about radiation hazards by indicating that the dentist will only take the minimum number of X-rays needed for an accurate diagnosis, minimizing the patient's exposure to radiation. This approach aligns with the principle of ALARA (As Low As Reasonably Achievable) in radiation safety, which aims to minimize radiation exposure while still obtaining necessary diagnostic information.
38.
The periapical film reveals
Correct Answer
D. The entire tooth, including apex
Explanation
The periapical film is a dental X-ray that provides a detailed image of a specific tooth and its surrounding structures. It captures the entire tooth, including the apex, which is the tip of the root. This allows dentists to assess the condition of the tooth, detect any abnormalities or pathology, and determine the need for treatment. The film does not show the entire jaw or both upper and lower teeth in the same image. It is specifically designed to focus on a single tooth and provide a close-up view.
39.
Interproximal film may show all of the following except
Correct Answer
B. Root tip fractures
Explanation
Interproximal films are dental X-rays that capture the areas between the teeth. These films are commonly used to detect dental issues such as incipient caries (early stage cavities), crest of alveolar bone (the bone that holds the teeth in place), and recurrent decay under existing restorations (decay beneath dental fillings or crowns). However, they are not typically used to identify root tip fractures, as these fractures are better visualized using periapical or panoramic X-rays. Therefore, root tip fractures would be the exception in this case.
40.
Which of these is not a factor when considering what size film to use?
Correct Answer
D. Patients previous radiation exposure
Explanation
When considering what size film to use, factors such as the patient's age, the size of their mouth opening, and the shape of their dental arches are important considerations. However, the patient's previous radiation exposure is not a factor that influences the choice of film size. This is because the previous radiation exposure does not directly affect the size of the film needed for dental imaging.
41.
The principle used in panoramic radiography is
Correct Answer
C. Horizontal curvature
Explanation
Panoramic radiography uses a technique called horizontal curvature. This technique involves the use of a curved dental X-ray machine that rotates around the patient's head, capturing a full panoramic image of the teeth and surrounding structures. The curved shape of the machine allows for a more accurate and comprehensive image, as it follows the natural curvature of the dental arch. This technique is commonly used in dentistry to assess the overall oral health and detect any abnormalities or issues in the teeth and jawbone.
42.
A material or substance that does not stop or absorb xrays is known as
Correct Answer
C. Radiolucent
Explanation
A material or substance that does not stop or absorb X-rays is known as radiolucent. This means that X-rays can pass through it easily, allowing for clear imaging of structures or objects behind the radiolucent material. Radiolucent materials are commonly used in medical imaging, such as X-rays or CT scans, to help visualize bones, organs, or other structures within the body.
43.
A material or substance that does stop or absorb xrays is known as
Correct Answer
B. Radiopaque
Explanation
Radiopaque is the correct answer because it refers to a material or substance that does stop or absorb X-rays. When X-rays pass through the body, radiopaque substances appear white on the X-ray image, allowing for the visualization of structures such as bones or dental fillings. This property is useful in medical imaging as it helps in identifying abnormalities or fractures in bones and detecting dental issues. Radiographic, radiolucent, and radiodontic are incorrect options as they do not accurately describe the property of stopping or absorbing X-rays.
44.
All of the tissues listed are radiopaque EXCEPT
Correct Answer
C. Pulp chamber
Explanation
The pulp chamber is the correct answer because it is not radiopaque. Radiopacity refers to the ability of a substance to block or absorb X-rays, making it appear white on a radiograph. Enamel, cortical plate, and alveolar bone are all radiopaque tissues, meaning they appear white on X-rays. However, the pulp chamber, which contains soft tissues like nerves and blood vessels, is not radiopaque and appears darker on X-rays.
45.
Which of these appears radiolucent?
Correct Answer
A. Caries
Explanation
Caries refers to tooth decay or cavities, which are areas of the tooth that have been damaged and demineralized by acid-producing bacteria. In radiographs, caries appear radiolucent because they allow more X-rays to pass through, resulting in a darker or less dense appearance compared to the surrounding healthy tooth structure. This is because the decayed area lacks the mineral content that would otherwise block or attenuate the X-rays. Therefore, caries are the correct answer as they appear radiolucent on dental radiographs.
46.
What is the name of the diagonal radiopaque line visible at the lower part of the roots of the mandibular molars?
Correct Answer
D. Internal oblique ridge
Explanation
The correct answer is internal oblique ridge. The internal oblique ridge is a radiopaque line that is visible on a dental radiograph at the lower part of the roots of the mandibular molars. It runs diagonally from the distal aspect of the mandibular first molar to the mesial aspect of the mandibular third molar. This ridge serves as an attachment site for the mylohyoid muscle and can help in identifying the location and orientation of the mandibular molars on a radiograph.
47.
What is the small circular radiolucency near the roots of the mandibular premolars called?
Correct Answer
B. Mental foramen
Explanation
The small circular radiolucency near the roots of the mandibular premolars is called the mental foramen.
48.
What term describes the U-shaped radiopaque structure often seen in maxillary molar films?
Correct Answer
C. Zygoma
Explanation
The U-shaped radiopaque structure often seen in maxillary molar films is called the zygoma.
49.
What is the thin radiopaque band between the maxillary incisors called?
Correct Answer
B. Nasal septum
Explanation
The thin radiopaque band between the maxillary incisors is called the nasal septum. It is a structure made up of cartilage and bone that separates the left and right nasal cavities. The nasal septum helps to support the nose and maintain its shape.
50.
What term describes the heavily radiopaque midpoint of the mandible?
Correct Answer
D. SympHysis
Explanation
The term "symphysis" refers to the heavily radiopaque midpoint of the mandible. The mandibular symphysis is the area where the two halves of the mandible fuse together during development. It is a prominent landmark in the lower jaw and can be easily identified on radiographs due to its high radiopacity. The other options, zygoma, odontoma, and hamulus, do not describe the heavily radiopaque midpoint of the mandible.