DANB RHS Radiation Health and Safety - Set 3 - Part 3

Correct Answer: horizontal angulation

Overlapped contacts mean the beam was not directed straight through the proximal surfaces, a horizontal angulation error that superimposes adjacent teeth and can hide interproximal caries between them. Option a is incorrect because vertical angulation errors change apparent tooth length, producing foreshortening or elongation, not the side-to-side superimposition that appears as overlapped proximal contacts. Option b is incorrect because exposure time affects density, how light or dark the image is, and has nothing to do with whether the proximal contacts are opened or overlapped. Option c is incorrect because the brand of receptor does not determine contact overlap; correct horizontal beam direction does, regardless of which manufacturer's digital receptor is actually used.

Correct Answer: insufficient vertical angulation

Too little vertical angulation stretches the projected image, producing elongation in which the teeth appear longer than they truly are; increasing the vertical angle appropriately corrects the elongation. Option a is incorrect because excessive vertical angulation does the opposite, compressing the image into foreshortening so the teeth look too short on the image rather than too long. Option c is incorrect because horizontal overlap superimposes the proximal contacts from a side-to-side aiming error; it muddles the contacts but does not lengthen the teeth. Option d is incorrect because a reversed receptor produces a faint image with a herringbone pattern, an exposure-side error, not a change in the apparent length of the teeth.

Correct Answer: a reversed receptor

Placing the receptor backward lets the beam pass through its lead backing first, leaving a faint image stamped with the backing's herringbone pattern, a clear sign the receptor was reversed. Option a is incorrect because too much exposure darkens the image overall; it does not lighten the picture or imprint the patterned mark left by a backward receptor. Option b is incorrect because fog from scatter veils the image with a gray haze that lowers contrast, but it does not create the distinct herringbone pattern of a reversed receptor. Option d is incorrect because patient movement blurs detail across the image, smearing structures, rather than producing the faint, patterned herringbone appearance left by a backward-placed receptor.

Correct Answer: patient or tubehead movement

Motion during that one exposure, whether the patient shifted or the tubehead drifted, smears detail on just that image, so a single blurred picture points to movement at the moment of exposure. Option b is incorrect because a scratched plate leaves the same mark in the same spot on image after image, a repeating artifact, not a one-time blur affecting only a single exposure. Option c is incorrect because low kilovoltage changes contrast, making the image harsh rather than blurred, so it does not explain why a single picture would suddenly lose its sharpness. Option d is incorrect because a reversed receptor yields a faint herringbone image, an exposure-direction fault, which is a different appearance from the motion blur described here.

Correct Answer: a damaged or scratched receptor

An artifact that repeats in the identical location across multiple images comes from the reused receptor itself, so a scratched or damaged plate or sensor is the cause and it should be replaced. Option a is incorrect because patient movement blurs a single exposure and varies from image to image; it cannot place an identical line in the same spot on several pictures. Option b is incorrect because a cone cut leaves an unexposed clear border from beam misalignment on one exposure, not a thin white line recurring in the same place across many images. Option c is incorrect because low exposure lightens an image overall and changes with each shot; it does not stamp a fixed white line repeatedly at the same location.

Correct Answer: a fresh barrier on the receptor

Digital receptors cannot withstand heat sterilization, so a fresh disposable barrier is placed over the sensor or plate for every patient to prevent cross-contamination during the procedure. Option a is incorrect because the lead apron is wiped and reused as patient shielding and is not the infection-control answer here; the receptor itself is what needs a fresh barrier each time. Option b is incorrect because a longer PID is a dose-reducing geometry choice, unrelated to infection control, so it does nothing to address the receptor that cannot be heat-sterilized. Option d is incorrect because kilovoltage governs image contrast and has no bearing on preventing cross-contamination, so changing it does not substitute for barrier protection of the receptor.

Correct Answer: one

The Universal system numbers the permanent teeth from one through thirty-two, beginning at the maxillary right third molar as tooth number one and continuing around the arches. Option a is incorrect because thirty-two is the last tooth in the sequence, the mandibular right third molar, not the starting maxillary right third molar where numbering begins. Option c is incorrect because sixteen marks the maxillary left third molar, the end of the upper arch, rather than the first tooth on the maxillary right where the count starts. Option d is incorrect because seventeen is the mandibular left third molar, where the lower arch numbering begins, so it does not identify the maxillary right third molar.

Correct Answer: facing the patient

Labial mounting, the method recommended by the American Dental Association, arranges images as if facing the patient, with the raised dot toward the viewer and the patient's right on the viewer's left. Option b is incorrect because standing behind the patient corresponds to lingual mounting with the dot in, the reverse orientation, so it does not describe the labial method asked about. Option c is incorrect because viewing from above the patient is not a recognized mounting convention; mounting is defined by facing the patient from the front, not looking down from overhead. Option d is incorrect because being inside the mouth is not a mounting viewpoint at all; mounting orients the finished images for an external viewer, conventionally one facing the patient.

Correct Answer: copies, on written request

The dental record stays with the practice, so the office releases copies rather than originals, and only after the patient submits a written request authorizing the transfer of the records. Option a is incorrect because the original images are part of the legal record the dentist must retain, so they are never handed over; the patient receives duplicates instead. Option b is incorrect because records cannot be withheld simply over a balance; a proper written request must be honored with copies, kept separate from any outstanding billing dispute. Option c is incorrect because verbal results alone do not satisfy a request for the images themselves; the patient is entitled to copies of the actual records upon written authorization.

Correct Answer: dentist

Although the patient pays for the service, the dentist owns the original images as part of the practice record and is responsible for retaining and safeguarding them over time. Option a is incorrect because the patient pays for and may obtain copies of the images, but ownership of the originals stays with the dentist who created and maintains the record. Option b is incorrect because the insurance company may receive copies to process a claim, yet it never owns the patient's original dental images held by the practice. Option d is incorrect because the software vendor supplies the imaging system but has no ownership of the clinical images themselves, which legally belong to the treating dentist of record.