NDAEB Exam Prep Questions &
Answers(RATED A+)
What two basic methods are used to acquire a digital x-ray image? -
ANSWER_Direct imaging(sensor) & indirect imaging(PSP)
Advantages of Digital Radiography - 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 - ANSWER_Cost, converting previous records
to digital, learning the computer software, thickness and rigidity of sensors, infection
control
What is intraoral film composed of? - 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? - ANSWER_The image on the film that is not yet visible
because it has not been processed.
What does 'film speed' refer to? - 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? -
ANSWER_True
What is the fastest film speed currently available? - 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? - ANSWER_Intraoral
film, extraoral film, and duplicating film.
When does a "Herringbone" pattern occur on dental film? - ANSWER_When it is
placed in the mouth backwards.
What are the 5 basic sizes that intraoral film comes in? - ANSWER_Child Size: 0
Narrow Anterior: 1
Adult Size: 2
Preformed bitewing: 3 (infrequently used)
Occlusal: 4
What are two common extraoral radiographs taken? - ANSWER_Panoramic and
Cephalometric.
,What is an intensifying screen? - 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? - 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? -
ANSWER_Bisecting & Paralleling
5 Basic Rules of the Paralleling Technique - 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? -
ANSWER_To ensure an area is not omitted or exposed twice.
What occurs if the horizontal angulation is incorrect? - ANSWER_Overlapping of
teeth.
What two errors can occur if the vertical angulation is incorrect? -
ANSWER_Foreshortened or elongated images.
What qualities must an endodontic x-ray have? - 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: - 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: - 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? - ANSWER_Use of a cone-shaped x-
ray beam to acquire three-dimensional information.
, What is a film grid? (used for extraoral imaging) - 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? - 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? - 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? - ANSWER_Ghost images
If a lead apron is incorrectly placed on a pt during a panoramic radiograph, what
occurs? - ANSWER_"Lead Apron Artifact" a radiopaque cone-shaped artifact results.
What happens if a patient's chin is positioned too high during a pan? - ANSWER_It
will create a "reverse smile line"
What happens if a patient's chin is positioned too low during a pan? - ANSWER_It
will create an "exaggerated smile line"
What are three types of stress and strain? - 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? - 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? - ANSWER_1. An organic resin
matrix.
2. Inorganic fillers.
3. A coupling agent.
4. pigments.
What is the resin matrix in a composite resin? - ANSWER_A fluid-like material called
dimethacrylate or BIS-GMA.
What is the filler in a composite resin? - 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: - ANSWER_Megafill, macrofill, midifill,
minifill, microfill, and nanofill.
Answers(RATED A+)
What two basic methods are used to acquire a digital x-ray image? -
ANSWER_Direct imaging(sensor) & indirect imaging(PSP)
Advantages of Digital Radiography - 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 - ANSWER_Cost, converting previous records
to digital, learning the computer software, thickness and rigidity of sensors, infection
control
What is intraoral film composed of? - 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? - ANSWER_The image on the film that is not yet visible
because it has not been processed.
What does 'film speed' refer to? - 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? -
ANSWER_True
What is the fastest film speed currently available? - 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? - ANSWER_Intraoral
film, extraoral film, and duplicating film.
When does a "Herringbone" pattern occur on dental film? - ANSWER_When it is
placed in the mouth backwards.
What are the 5 basic sizes that intraoral film comes in? - ANSWER_Child Size: 0
Narrow Anterior: 1
Adult Size: 2
Preformed bitewing: 3 (infrequently used)
Occlusal: 4
What are two common extraoral radiographs taken? - ANSWER_Panoramic and
Cephalometric.
,What is an intensifying screen? - 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? - 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? -
ANSWER_Bisecting & Paralleling
5 Basic Rules of the Paralleling Technique - 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? -
ANSWER_To ensure an area is not omitted or exposed twice.
What occurs if the horizontal angulation is incorrect? - ANSWER_Overlapping of
teeth.
What two errors can occur if the vertical angulation is incorrect? -
ANSWER_Foreshortened or elongated images.
What qualities must an endodontic x-ray have? - 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: - 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: - 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? - ANSWER_Use of a cone-shaped x-
ray beam to acquire three-dimensional information.
, What is a film grid? (used for extraoral imaging) - 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? - 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? - 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? - ANSWER_Ghost images
If a lead apron is incorrectly placed on a pt during a panoramic radiograph, what
occurs? - ANSWER_"Lead Apron Artifact" a radiopaque cone-shaped artifact results.
What happens if a patient's chin is positioned too high during a pan? - ANSWER_It
will create a "reverse smile line"
What happens if a patient's chin is positioned too low during a pan? - ANSWER_It
will create an "exaggerated smile line"
What are three types of stress and strain? - 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? - 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? - ANSWER_1. An organic resin
matrix.
2. Inorganic fillers.
3. A coupling agent.
4. pigments.
What is the resin matrix in a composite resin? - ANSWER_A fluid-like material called
dimethacrylate or BIS-GMA.
What is the filler in a composite resin? - 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: - ANSWER_Megafill, macrofill, midifill,
minifill, microfill, and nanofill.
