DANB RHS Radiation Health and Safety - Set 2 - Part 1

Correct Answer: periapical

A periapical captures the whole tooth, including the apex and a margin of bone around it, which makes it the view for root tips, periapical lesions, and endodontic follow-up. Option a is incorrect because a bitewing stops at the crowns of both arches and the crestal bone, so it never reaches the roots or apex that this question is asking the image to show. Option c is incorrect because an occlusal view surveys a broad section of one arch from a biting angle; it is built to locate stones or roots over a wide area, not to detail one tooth's apex. Option d is incorrect because a cephalometric is an extraoral skull projection for orthodontic measurement, far too broad and superimposed to display a single tooth from crown to root tip.

Correct Answer: four

A standard adult posterior bitewing examination uses four views, the right and left premolar and molar projections, which together open the contacts across the back teeth of both arches. Option a is incorrect because a single bitewing would capture only one small region of contacts, leaving most of the posterior teeth in both arches unexamined and many interproximal surfaces unseen. Option b is incorrect because two views still fall short of the routine posterior survey; the molar and premolar areas on each side need their own projections to open every back contact. Option c is incorrect because six is more than the routine posterior set requires; that number drifts toward a fuller survey rather than the standard four-film bitewing examination described here.

Correct Answer: bitewing

The bitewing opens the proximal contacts without root overlap and shows the crowns of both arches and the crestal bone, making it the key view for early decay and bone loss between teeth. Option b is incorrect because a periapical shows whole roots and the apex, useful detail in its own right, but its field and root superimposition make it less ideal than the bitewing for the contacts. Option c is incorrect because a panoramic overlaps the contact areas and offers lower detail, so small interproximal lesions and subtle crestal changes can be missed on this broad survey view. Option d is incorrect because a cephalometric measures the skull profile for orthodontics; it does not image individual tooth contacts at all, so it cannot reveal decay or bone loss between teeth.

Correct Answer: periapicals and bitewings

A full mouth series is built from periapicals plus bitewings, commonly around eighteen to twenty images, giving whole-tooth detail along with open-contact views across the entire dentition. Option a is incorrect because a panoramic alone is a single broad survey, not a series of detailed intraoral films; it cannot supply the close interproximal and apical detail a full mouth series provides. Option b is incorrect because occlusals and cephalometrics are special-purpose projections for arch overviews and orthodontic measurement, not the combination that defines a routine full mouth examination. Option d is incorrect because CBCT produces three-dimensional reconstructed slices used for complex planning; it is a separate modality and is not what the term full mouth series refers to.

Correct Answer: periapical

Endodontic length checks need the apex and the bone just beyond it in view, and the periapical is the projection that reliably includes the root tip with that surrounding margin. Option a is incorrect because a bitewing ends at the crowns and crestal bone and never reaches the apex, so it cannot confirm how far an instrument or filling extends toward the root tip. Option c is incorrect because an occlusal view covers a wide arch segment from a biting angle and lacks the focused apical detail required to judge working length on a single root. Option d is incorrect because a panoramic surveys the whole jaws with lower detail and contact overlap, which is too imprecise for measuring the fine working length inside an individual canal.

Correct Answer: mandibular occlusal

The mandibular occlusal images the floor of the mouth, the region where the submandibular gland and its duct lie, so it is the projection that can demonstrate a salivary stone there. Option b is incorrect because the maxillary occlusal directs its beam down to image the palate and upper arch, away from the floor of the mouth where a submandibular stone would sit. Option c is incorrect because a lateral cephalometric is an extraoral profile view for orthodontics; it surveys the skull, not the floor of the mouth, so it is not used to locate this stone. Option d is incorrect because a posterior bitewing shows only crowns and crestal bone of the back teeth, a small intraoral field that does not include the salivary gland region at all.

Correct Answer: blurred or distorted

Only structures within the focal trough, the curved image layer matching the arch, are recorded sharply; anything outside that zone falls out of focus and appears blurred or distorted. Option a is incorrect because appearing sharper is the opposite of what happens; sharpness is reserved for objects inside the trough, while those beyond it lose definition rather than gaining it. Option b is incorrect because brightness reflects exposure and density settings, not position relative to the trough, so being outside the focal layer does not simply brighten a structure. Option c is incorrect because structures may change size as well, but calling it larger only ignores the loss of focus; the defining result outside the trough is blur and shape distortion.

Correct Answer: opposite side and higher

A ghost arises when the beam passes through a dense object and projects it across to the opposite side, higher, larger, and blurrier than the real structure that created it. Option a is incorrect because placing the ghost on the same side and lower reverses its actual behavior; the artifact crosses to the other side and sits higher than the object that produced it. Option b is incorrect because a ghost is never centered and sharp; it is an out-of-focus duplicate, so describing it as crisp and central contradicts the smeared, displaced look it always has. Option d is incorrect because appearing at the real object's exact position would make it a true image, not a ghost; the whole point is that the ghost is shifted and magnified elsewhere.

Correct Answer: size four

The adult occlusal uses the large size four receptor, which the patient bites to hold flat, so it can capture a broad section of the palate or floor of the mouth in one image. Option b is incorrect because size zero is the smallest receptor, made for young children's small mouths and anterior placement, far too little coverage for an adult occlusal survey of the arch. Option c is incorrect because size one is a narrow receptor used for adult anterior intraoral views; it lacks the breadth needed to image a whole arch segment from the biting plane. Option d is incorrect because size two is the standard intraoral size for periapicals and bitewings, not the larger plate the patient bites to obtain a broad occlusal projection.

Correct Answer: panoramic

The panoramic delivers a single sweeping survey of both arches, the sinuses, and the temporomandibular joints, which is why it is chosen for wide findings like impactions and broad pathology. Option a is incorrect because a bitewing captures only crowns and crestal bone of a few posterior teeth, a narrow field that comes nowhere near surveying the sinuses or the joints. Option b is incorrect because a periapical details one or two teeth with their roots, useful for focused problems but far too small to take in both jaws, the sinuses, and the joints at once. Option c is incorrect because an occlusal images a broad section of just one arch from a biting angle; it still cannot display both jaws, the sinuses, and the joints together in a single survey.

Correct Answer: cephalostat

The cephalostat uses ear rods seated in the ear canals to fix the head in a reproducible position, so serial cephalometric images can be compared accurately over a course of treatment. Option a is incorrect because a bite block stabilizes a receptor inside the mouth for intraoral views; it does not orient the whole head the way the cephalostat does for an extraoral projection. Option c is incorrect because a position indicating device aims and shapes the x-ray beam from the tubehead; it directs radiation rather than holding the patient's head in a fixed cephalometric pose. Option d is incorrect because a receptor holder grips an intraoral sensor or plate in place; it has no role in standardizing skull orientation for a reproducible cephalometric measurement.

Correct Answer: orthodontic profile analysis

The lateral cephalometric shows the side profile of the facial bones along with the soft-tissue profile, which makes it the standard view for orthodontic analysis and tracking growth. Option a is incorrect because interproximal caries is found on bitewings, which open the contacts between teeth; the cephalometric is far too broad and superimposed to reveal decay on tooth surfaces. Option b is incorrect because salivary stones in the floor of the mouth are demonstrated on a mandibular occlusal, not on a profile skull projection meant for orthodontic measurement. Option d is incorrect because crestal bone loss is assessed on bitewings and periapicals that show the bone between teeth; a lateral skull view cannot resolve those fine alveolar levels.

Correct Answer: CBCT

CBCT rotates around the patient and reconstructs a volume that can be viewed in axial, coronal, and sagittal planes, so it is the only true three-dimensional dental imaging method. Option b is incorrect because a panoramic is a flattened two-dimensional survey of the jaws; though broad, it collapses depth onto one plane and cannot supply real three-dimensional information. Option c is incorrect because a bitewing is a single flat intraoral image of the crowns and crestal bone, so it shares the two-dimensional limit and offers no depth reconstruction. Option d is incorrect because an occlusal view is likewise a flat projection of one arch; it captures area but not volume, so it cannot resolve buccal-versus-lingual depth in three dimensions.

Correct Answer: higher

CBCT delivers more radiation than ordinary intraoral imaging, roughly the order of several full-mouth series, though it remains lower than medical CT, so it is reserved for cases that justify three dimensions. Option a is incorrect because claiming a far lower dose is incorrect; the volumetric acquisition takes many basis images, so CBCT exposes the patient to more radiation than a couple of intraoral films. Option b is incorrect because the dose is not identical to intraoral imaging; reconstructing a full volume requires substantially more exposure than a single small periapical or bitewing. Option c is incorrect because no x-ray examination delivers essentially zero dose, and CBCT in particular carries a meaningful dose, which is exactly why its use must be justified.

Correct Answer: ruin the whole volume

Because the reconstruction depends on many basis images taken during rotation, movement blurs the data across the entire dataset, so motion can degrade or ruin the whole volume, not just one slice. Option a is incorrect because motion never sharpens an image; it smears the captured projections, so the reconstructed volume loses definition rather than gaining the crispness this option claims. Option b is incorrect because the dose is set by the exposure parameters of the scan, not by whether the patient moves, so movement does not lower the radiation the patient receives. Option d is incorrect because the field of view is chosen before the scan and fixed by the equipment settings; patient movement degrades the image quality but does not shrink that selected field.

Correct Answer: receptor

The distinction rests solely on where the receptor sits: inside the mouth makes the image intraoral, outside the mouth makes it extraoral. The x-ray source is always outside the patient regardless. Option a is incorrect because the x-ray tube stays outside the patient for every dental image, intraoral or extraoral alike, so its location cannot be what separates the two categories. Option c is incorrect because the patient's head is positioned for many views, but head placement does not define the category; the receptor's location inside or outside the mouth is the deciding factor. Option d is incorrect because the control panel sits at the operator's station for any exposure; it has nothing to do with whether the receptor is inside or outside the patient's mouth.

Correct Answer: PSP plate

The photostimulable phosphor plate stores a latent image that a laser scanner must read out before the picture appears, so unlike the solid-state sensors it does not display instantly. Option b is incorrect because a CCD sensor is a solid-state receptor that converts the exposure to a signal at once, sending a near-instant image to the screen with no separate scanning step. Option c is incorrect because a CMOS sensor is likewise a solid-state receptor delivering an immediate image; it is wired or wireless but never requires a laser scan to reveal the picture. Option d is incorrect because a wired solid-state sensor describes the CCD or CMOS family, which is exactly the instant-image type; it is the opposite of the plate that must be scanned first.

Correct Answer: solid-state sensor

Solid-state CCD and CMOS sensors are rigid and frequently cabled, and they convert the exposure to a signal immediately, putting the image on the monitor within seconds of the shot. Option a is incorrect because a PSP plate is thin and flexible, not rigid, and it must be laser-scanned before the image appears, so it does not provide the near-instant display described. Option b is incorrect because a phosphor plate is just another name for the PSP, sharing the same flexible, scan-after-exposure behavior, which is the opposite of an instant rigid sensor. Option d is incorrect because a film packet is a chemical medium requiring processing and is not even a digital receptor, so it neither displays instantly nor matches the rigid sensor described.

Correct Answer: outside the patient

In all dental radiography the tubehead that produces the beam sits outside the patient and directs radiation through the tissues to the receptor, whether that receptor is inside or outside the mouth. Option a is incorrect because placing the source inside the mouth describes the receptor in intraoral imaging, not the x-ray source; the beam-producing tubehead always remains outside the patient. Option b is incorrect because the receptor only captures the beam after it passes through tissue; it does not generate x-rays, so the source is not within the receptor itself. Option c is incorrect because saying the source is behind the film confuses the capture side with the source side; the radiation originates at the external tubehead and travels toward the film.

Correct Answer: recurring artifacts on images

Because the same plate is reused, physical scratches and wear leave marks that reappear in the same spot on image after image, so worn plates create recurring artifacts and should be replaced. Option b is incorrect because scratches degrade the recording surface rather than enhancing it, so they cannot brighten or sharpen contrast; they add unwanted marks instead of improving the image. Option c is incorrect because wear has no effect on how fast the laser reads the plate; scanning speed is a property of the scanner, not of damage on the phosphor surface. Option d is incorrect because patient dose depends on exposure settings, not on plate condition; in fact a damaged plate may force a retake, which would raise rather than lower the dose.