NDAEB Exam Prep 2024 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) 1 / 4
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)
- Rinsing (remove developer from film)
- Fixing. (use an acidic solution to remove unexposed silver halide crystals)
- Washing (wash the film)
- Drying
- Basic Rules of the Paralleling Technique - correct answer 1. Placement: it must cover correct teeth to
- Position: it must be parallel to the long axis of the tooth. 2 / 4
What are the two techniques that can be used for exposing intraloral images? - correct answer Bisecting & Paralleling
be examined
- Vertical Angulation: Central ray must be directed perpendicular to the receptor & tooth.
- 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)
- 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. 3 / 4
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.
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