NDAEB EXAM PREP QUESTIONS WITH 100%
CORRECT ANSWERS
What two basic methods are used to acquire a digital x-ray image? - correct answer -Direct
imaging(sensor) & indirect imaging(PSP)
Advantages of Digital Radiography - correct answer -Immediate viewing of images, less radiation, no
chemicals, ability to enhance images, communication with other dentists, no more lost films, remote
consultation capability
Disadvantages of Digital Radiography - correct answer -Cost, converting previous records to digital,
learning the computer software, thickness and rigidity of sensors, infection control
What is intraoral film composed of? - correct answer -Film Base - Clear Cellulose Acetate
Thin Adhesive Layer
Silver Halide Crystals - absorb radiation
A protective layer to protect the emulsion surface.
What is a latent image? - correct answer -The image on the film that is not yet visible because it has not
been processed.
What does 'film speed' refer to? - correct answer -The amount of radiation that is required to produce a
radiograph of standard density.
True or false: The larger the silver halide crystals, the faster the film speed? - correct answer -True
What is the fastest film speed currently available? - correct answer -F-Speed. (It reduces patient
exposure to radiation by 20-60% compared to E or D speed film)
What are the 3 types of x-ray film used in dental radiography? - correct answer -Intraoral film, extraoral
film, and duplicating film.
When does a "Herringbone" pattern occur on dental film? - correct answer -When it is placed in the
mouth backwards.
What are the 5 basic sizes that intraoral film comes in? - correct answer -Child Size: 0
Narrow Anterior: 1
Adult Size: 2
Preformed bitewing: 3 (infrequently used)
Occlusal: 4
What are two common extraoral radiographs taken? - correct answer -Panoramic and Cephalometric.
,What is an intensifying screen? - correct answer -A device that intensifies or increases the effect of
radiation and thus decreases the amount of exposure time needed. It is coated with phosphor which
gives off light when struck by x-radiation.
What are the 5 steps in processing film? - correct answer -1. Developing (reduce the silver halide crystals
into black metallic silver)
2. Rinsing (remove developer from film)
3. Fixing. (use an acidic solution to remove unexposed silver halide crystals)
4. Washing (wash the film)
5. Drying
What are the two techniques that can be used for exposing intraloral images? - correct answer -
Bisecting & Paralleling
5 Basic Rules of the Paralleling Technique - correct answer -1. Placement: it must cover correct teeth to
be examined
2. Position: it must be parallel to the long axis of the tooth.
3. Vertical Angulation: Central ray must be directed perpendicular to the receptor & tooth.
4. Horizontal Angulation: Central ray must be directed through the contact areas.
5. Central Ray: it must be centered on the receptor.
Why is it important to have an 'exposure sequence' for receptor placement? - correct answer -To ensure
an area is not omitted or exposed twice.
What occurs if the horizontal angulation is incorrect? - correct answer -Overlapping of teeth.
What two errors can occur if the vertical angulation is incorrect? - correct answer -Foreshortened or
elongated images.
What qualities must an endodontic x-ray have? - correct answer -Tooth centered on the image
At least 5mm of bone visible beyond apex of the tooth
The image is as anatomically accurate as possible
Two methods of mounting radiographs are: - correct answer -1. Labial mounting method: radiographs
placed in the mount with the raised dots facing up (as if the viewer is looking directly at the pt)
2. radiographs placed in the mount with the raised dots facing down (as if the viewer is inside the
patients mouth looking out)
Two types of panoramic machines are in use today: - correct answer -Film-based imaging & direct digital
imaging. The main difference is the image receptor, digital units use a sensory array rather than film.
What is Cone Beam Computed Tomography? - correct answer -Use of a cone-shaped x-ray beam to
acquire three-dimensional information.
What is a film grid? (used for extraoral imaging) - correct answer -It is used to reduce the amount of
scatter radiation that reaches an extraoral film during exposure.
, What is a Lateral Cephalometric Projection used for? - correct answer -Used to evaluate facial growth
and development, trauma, disease, and developmental abnormalities. It shows the bones of the face
and skull as well as the soft tissue profile.
What is a Posteroanterior Projection used for? - correct answer -Used to evaluate facial growth and
development, trauma, disease, and development abnormalities. It shows the frontal and ethmoid
sinuses, the orbits, and the nasal cavities.
What happens if a patient does not remove jewellery or metallic/radiodense objects from their
head/neck? - correct answer -Ghost images
If a lead apron is incorrectly placed on a pt during a panoramic radiograph, what occurs? - correct
answer -"Lead Apron Artifact" a radiopaque cone-shaped artifact results.
What happens if a patient's chin is positioned too high during a pan? - correct answer -It will create a
"reverse smile line"
What happens if a patient's chin is positioned too low during a pan? - correct answer -It will create an
"exaggerated smile line"
What are three types of stress and strain? - correct answer -Tensile stress: pulls and stretches a material
Ex. tug-of-war
Compressive stress: pushes a material together. ex. chewing
Shear stress: the breakdown of material as the result of something sliding over two areas. ex. cutting
with scissors.
What is amalgam alloy powder composed of? - correct answer -Silver - gives it its strength.
Tin - gives it workability and strength.
Copper - gives it strength and resistance to corrosion.
Zinc - to suppress oxidation.
What is the composition of a composite resin? - correct answer -1. An organic resin matrix.
2. Inorganic fillers.
3. A coupling agent.
4. pigments.
What is the resin matrix in a composite resin? - correct answer -A fluid-like material called
dimethacrylate or BIS-GMA.
What is the filler in a composite resin? - correct answer -Inorganic fillers in a composite resin include
quartz, glass, silica particles, and colorants. They add strength and other characteristics needed in a
restorative material.
Composites are classified by particle size as: - correct answer -Megafill, macrofill, midifill, minifill,
microfill, and nanofill.
What is the coupling agent used for in a composite resin? - correct answer -It strengthens the resin by
chemically bonding the filler to the resin matrix.
CORRECT ANSWERS
What two basic methods are used to acquire a digital x-ray image? - correct answer -Direct
imaging(sensor) & indirect imaging(PSP)
Advantages of Digital Radiography - correct answer -Immediate viewing of images, less radiation, no
chemicals, ability to enhance images, communication with other dentists, no more lost films, remote
consultation capability
Disadvantages of Digital Radiography - correct answer -Cost, converting previous records to digital,
learning the computer software, thickness and rigidity of sensors, infection control
What is intraoral film composed of? - correct answer -Film Base - Clear Cellulose Acetate
Thin Adhesive Layer
Silver Halide Crystals - absorb radiation
A protective layer to protect the emulsion surface.
What is a latent image? - correct answer -The image on the film that is not yet visible because it has not
been processed.
What does 'film speed' refer to? - correct answer -The amount of radiation that is required to produce a
radiograph of standard density.
True or false: The larger the silver halide crystals, the faster the film speed? - correct answer -True
What is the fastest film speed currently available? - correct answer -F-Speed. (It reduces patient
exposure to radiation by 20-60% compared to E or D speed film)
What are the 3 types of x-ray film used in dental radiography? - correct answer -Intraoral film, extraoral
film, and duplicating film.
When does a "Herringbone" pattern occur on dental film? - correct answer -When it is placed in the
mouth backwards.
What are the 5 basic sizes that intraoral film comes in? - correct answer -Child Size: 0
Narrow Anterior: 1
Adult Size: 2
Preformed bitewing: 3 (infrequently used)
Occlusal: 4
What are two common extraoral radiographs taken? - correct answer -Panoramic and Cephalometric.
,What is an intensifying screen? - correct answer -A device that intensifies or increases the effect of
radiation and thus decreases the amount of exposure time needed. It is coated with phosphor which
gives off light when struck by x-radiation.
What are the 5 steps in processing film? - correct answer -1. Developing (reduce the silver halide crystals
into black metallic silver)
2. Rinsing (remove developer from film)
3. Fixing. (use an acidic solution to remove unexposed silver halide crystals)
4. Washing (wash the film)
5. Drying
What are the two techniques that can be used for exposing intraloral images? - correct answer -
Bisecting & Paralleling
5 Basic Rules of the Paralleling Technique - correct answer -1. Placement: it must cover correct teeth to
be examined
2. Position: it must be parallel to the long axis of the tooth.
3. Vertical Angulation: Central ray must be directed perpendicular to the receptor & tooth.
4. Horizontal Angulation: Central ray must be directed through the contact areas.
5. Central Ray: it must be centered on the receptor.
Why is it important to have an 'exposure sequence' for receptor placement? - correct answer -To ensure
an area is not omitted or exposed twice.
What occurs if the horizontal angulation is incorrect? - correct answer -Overlapping of teeth.
What two errors can occur if the vertical angulation is incorrect? - correct answer -Foreshortened or
elongated images.
What qualities must an endodontic x-ray have? - correct answer -Tooth centered on the image
At least 5mm of bone visible beyond apex of the tooth
The image is as anatomically accurate as possible
Two methods of mounting radiographs are: - correct answer -1. Labial mounting method: radiographs
placed in the mount with the raised dots facing up (as if the viewer is looking directly at the pt)
2. radiographs placed in the mount with the raised dots facing down (as if the viewer is inside the
patients mouth looking out)
Two types of panoramic machines are in use today: - correct answer -Film-based imaging & direct digital
imaging. The main difference is the image receptor, digital units use a sensory array rather than film.
What is Cone Beam Computed Tomography? - correct answer -Use of a cone-shaped x-ray beam to
acquire three-dimensional information.
What is a film grid? (used for extraoral imaging) - correct answer -It is used to reduce the amount of
scatter radiation that reaches an extraoral film during exposure.
, What is a Lateral Cephalometric Projection used for? - correct answer -Used to evaluate facial growth
and development, trauma, disease, and developmental abnormalities. It shows the bones of the face
and skull as well as the soft tissue profile.
What is a Posteroanterior Projection used for? - correct answer -Used to evaluate facial growth and
development, trauma, disease, and development abnormalities. It shows the frontal and ethmoid
sinuses, the orbits, and the nasal cavities.
What happens if a patient does not remove jewellery or metallic/radiodense objects from their
head/neck? - correct answer -Ghost images
If a lead apron is incorrectly placed on a pt during a panoramic radiograph, what occurs? - correct
answer -"Lead Apron Artifact" a radiopaque cone-shaped artifact results.
What happens if a patient's chin is positioned too high during a pan? - correct answer -It will create a
"reverse smile line"
What happens if a patient's chin is positioned too low during a pan? - correct answer -It will create an
"exaggerated smile line"
What are three types of stress and strain? - correct answer -Tensile stress: pulls and stretches a material
Ex. tug-of-war
Compressive stress: pushes a material together. ex. chewing
Shear stress: the breakdown of material as the result of something sliding over two areas. ex. cutting
with scissors.
What is amalgam alloy powder composed of? - correct answer -Silver - gives it its strength.
Tin - gives it workability and strength.
Copper - gives it strength and resistance to corrosion.
Zinc - to suppress oxidation.
What is the composition of a composite resin? - correct answer -1. An organic resin matrix.
2. Inorganic fillers.
3. A coupling agent.
4. pigments.
What is the resin matrix in a composite resin? - correct answer -A fluid-like material called
dimethacrylate or BIS-GMA.
What is the filler in a composite resin? - correct answer -Inorganic fillers in a composite resin include
quartz, glass, silica particles, and colorants. They add strength and other characteristics needed in a
restorative material.
Composites are classified by particle size as: - correct answer -Megafill, macrofill, midifill, minifill,
microfill, and nanofill.
What is the coupling agent used for in a composite resin? - correct answer -It strengthens the resin by
chemically bonding the filler to the resin matrix.
