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Radiography
Radiography portion of NBDHE
| Question | Answer |
|---|---|
| During radiographic exposure, if the vertical angulation of the cone is too flat, the image on the film becomes distorted. Which term BEST describes the appearance of the tooth? | Elongated |
| What appears as a radiopaque intersection of the maxillary sinus and the nasal cavity as viewed on a dental radiograph? | Inverted Y |
| In digital radiography, how do the exposure times differ from those required for conventional radiography? | 50%-80% less |
| Which projection is used to evaluate fractures of the zygomatic arch and the position of the condyles and to demonstrate the base of the skull? | Submentovertex |
| Which of the following bitewing-size film is used to examine permanent posterior teeth of children and, when positioned vertically, can be used to examine anterior teeth in adults? | Size 2 |
| Using 10 milliamperes (mA) with an exposure time of 3 seconds would result in 30 mAs. If the milliamperage is increased to 15, the time must be decreased to __________seconds to maintain the same density of the exposed radiograph. | 1.0 |
| Which form of the x-ray beam is MOST detrimental to the client and the operator? | Primary radiation |
| When taking a radiograph, how many inches is the recommended size of the beam at the client’s face? | 2.75 |
| The radiopaque line observed on the panoramic radiograph that runs horizontally across the maxilla from molar to molar is caused by the: | Palate |
| If the image of the _____ is seen on a panoramic radiograph, its location is near the maxillary lateral to lateral region and does not appear as a white line | Nose |
| The pterygoid plate images are located | posterior to the maxillary molars |
| The floor of the maxillary sinus is visible in the anterior region of the maxilla (T/F) | False |
| If the tongue is not placed on the roof of the mouth | A radiolucent shadow will be superimposed over the apices of the maxillary teeth |
| The recommended vertical angulation of the central ray of the x-ray beam should be directed at ____. This ___ degree vertical angulation is used to compensate for the slight bend of the upper portion of the film and the slight tilt of the maxillary teeth | +10 degrees |
| If 0 angulation is used for BWX | the bite-wing image will become distorted |
| If a negative vertical angulation is used for BWX | The occlusal surfaces of the maxillary teeth are evident and the apical regions of the mandibular teeth are seen. This causes distortion. |
| A bite-wing radiograph exposed with an excessive negative vertical angulation is | Nondiagnostic |
| The radiopaque line mainly composed of dense cortical bone found above the apices of the maxillary premolars and molar | The floor of the maxillary sinus |
| Is a large radiolucent area on the pano | The maxillary sinus |
| Radiolucent bands on radiographs | Nutrient canals |
| A radiopaque structure observed superior to the maxillary posterior teeth that join the maxilla and frontal and temporal bones | The zygomatic process |
| During a pano a loss of detail in the maxillary region will occur if the patient's head is positioned too high or is tipped upward (T/F) | True |
| If during the pano the patient's head is positioned too high or tipped upward | The mandibular condyle may be visible |
| ______________ will occur if the patient's head is positioned too low or tipped downward | An exaggerated smile line |
| A large radiolucent area in the posterior body of the mandible that represents the lingual depression for the submandibular gland. It is inferior to the mylohyoid ridge | The submandibular fossa |
| A radiolucent horizontal canal in the mandible through which the inferior alveolar nerve and artery pass; extends anteriorly from the mandibular foramen; most often identified by two faint parallel radiopaque lines representing the canal walls. | The mandibular canal |
| A radiopaque ridge created by the raised bony structure on the facial side of the mandible for the attachment of the buccinator muscle; superior to the internal oblique ridge | The external oblique ridge |
| A circular radiolucency on the facial aspect | The mental foramen |
| The light appearance of dental radiograph is due to | Inadequate development time |
| An accidental exposure to white light would cause radiographs to be | Dark |
| A concentrated developer solution would cause the films to be | Dark and lack contrast |
| Developer solution too hot would cause the films to be | Dark |
| Light films are caused by a___ in KVP setting | Decrease |
| Fasting blood glucose normal readings are | Less than 126 mg/dL |
| Blood glucose level is uncontrolled | Test values of more than 160 mg/dL |
| The BEST reason for the presence of a patient's maxillary diastema is | Labial frenum |
| Increasing the exposure time of films will | Increase the density and control the lightness. Increased exposure time provides more x-ray photons to interact with emulsion. |
| What is the purpose of the lead collimator on radiology equipment? | Restricts the size of the x-ray beam. |
| Which measurement is used to compare the biologic effects of different types of radiation? | Rem |
| The traditional unit for radiation absorbed dose—the amount of radiation absorbed by tissue | Rad |
| Système International (SI) unit for radiation absorbed dose | Grey, (GY) |
| The tradition unit of exposure that is the measurement of ionization in air produced by x-rays. | Roentgen |
| The annual radiation maximum permissible dose for occupationally exposed workers is: | 50 mSv |
| Describes the use of filtration in a dental x-ray tubehead? | Removes the less-penetrating x-rays from the beam |
| Lead apron absorbs____% of scatter radiation | 90 |
| How many impulses equal 1/4 second exposure time? | 15 impulses |
| As you go from D-speed to E-speed film exposure time approx. | halved |
| X-rays are generated when a stream of electrons traveling from one side of an x-ray tube is suddenly stopped by its impact on the | tungsten target of the anode |
| The mA setting controls | Density, # of protons, # of free electrons, and thermionic emission. |
| Reduces % of low energy x-rays in the beam | aluminum filtration |
| Mean penetrability of an x-ray beam related to | kVp, filtration, wavelength |
| A Rad tech received a dose of 3 Sieverts 4 feet from the source, how many Sv from 2 feet? | 12 |
| Proper BWX exposure: 1 second, 8 inches away=_____seconds, 16 inches away. | 4 |
| For optimal BWX settings should be: | 65 kVp, 10mA |
| Factor controls quality of the x-ray beam and thus, film contrast | Aluminum filtration |
| Increasing kVp results in | Long scale of contrast |
| Image magnification results from decreased | target-film-distance |
| Exposure time and mA control | # of x-rays produced |
| GBX II filters are needed for extraoral radiographs due to: | Film is more sensitive to visible light |
| The optimal operating temp. for dental automatic processors is | 82 degrees |
| The primary purpose of sodium thiosulfate is to | Remove the silver bromide crystals that have not been developed |
| Films not fixed for a long enough period of time will appear | to have a brown tint |
| The minimal total aluminum filtration on a dental x-ray machine capable of operating at 70kVp and above is | 2.5 mm Al |
| Cells sensitive to radiation damage | Ovaries, sperm cells |
| Cells insensitive to radiation damage | Spinal tissues, mature bone |
| The max amount of radiation an occupationally exposed person should receive in one year is; one week is | 0.05 Sv; 100mrem |
| PID types in order of least-most safe | Short, round->Long, round->Long, rectangular-> Long, rectangular, lead-lined |
| An ill-defined radiolucency with a calcification at the apex of a vital root tip is | benign cemental dysplasia (cemmentoma) |
| Proper thickness of lead lining in radiographic lead aprons | 0.25 mm equivalent |
| Intensifying screens in pano cassettes are necessary to | Reduce patient exposure |
| A film that has turned brown after the span of one year may have resulted from | insufficient wash |
| Most radiolucent dental material seen in radiographs | Acrylic |
| Earliest sign of overexposure to x-radiation | Erythema |
| The greatest cause of human radiation effects in dental radiography involves | Free radicals of water |
| Cell sensitivity to radiation is most pronounced during | Mitosis, periods of increased metabolism, embryonic development |
| Tissue damage increases with decreased | Cell differentiation |
| The effect of excessive angulation | Foreshortening |
| In bisecting the angle technique, the central ray is directed perpendicular to | An imaginary line bisecting the film and tooth |
| Bisecting the angle can often lead to | Foreshortening |
| Light leaks, faulty safelight, and chemistry which is too hot can create | Film fog |
Created by:
KatGallo