DANB RHS Radiation Health and Safety - Set 1 - Part 3

Correct Answer: shares nerves with the molars

The maxillary sinus shares sensory nerve supply with the upper posterior teeth, so sinus inflammation can be felt as molar pain, a referred ache that can be mistaken for a tooth problem. Option a is incorrect because the sinus is an air-filled cavity and contains no teeth, so the resemblance to a toothache comes from shared nerves, not from teeth located inside it. Option b is incorrect because the sinus is radiolucent because it holds air, not radiopaque; in any case its appearance on the image does not explain why its pain feels like a toothache. Option c is incorrect because the sinus holds no pulp tissue; pulp exists only inside teeth, so the referred pain is a matter of shared innervation rather than any pulp within the sinus.

Correct Answer: condyle, fossa, and eminence

A panoramic shows the bony components of the joint, namely the mandibular condyle, the glenoid fossa, and the articular eminence, while the soft tissues of the joint stay invisible on plain film. Option a is incorrect because the disc and ligaments are soft tissues that do not absorb enough of the beam to register, so they cannot be evaluated on a plain panoramic image. Option b is incorrect because the muscles of mastication are soft tissue as well; they move the joint but do not show on radiographs, which display dense bony structures. Option d is incorrect because enamel and dentin are tooth tissues, not parts of the joint at all, so naming them confuses the question about the bony anatomy of the TMJ.

Correct Answer: CBCT or arthrography

The disc is soft tissue, so plain radiography cannot show it; arthrography or CBCT is needed to evaluate the disc and the other soft-tissue components of the joint. Option b is incorrect because a bitewing images the crowns and crestal bone of posterior teeth, a small intraoral field that does not even include the joint, let alone its soft tissues. Option c is incorrect because an occlusal view surveys a section of one arch from a biting angle; it captures bone and teeth, not the soft articular disc inside the joint. Option d is incorrect because a faster receptor only reduces the dose or exposure time; speed cannot make soft tissue like the disc visible when plain radiography fundamentally cannot show it.

Correct Answer: radiolucent air space

The sinus is filled with air, which barely absorbs x-rays, so it appears as a dark radiolucent space above the posterior teeth, usually outlined by a thin radiopaque bony wall. Option a is incorrect because a radiopaque mass means dense tissue blocking the beam, but an air-filled cavity does the reverse, letting x-rays through and appearing dark on the image. Option b is incorrect because a dense metal shape describes a restoration or implant; the sinus contains air, not metal, so it cannot present as a bright metallic form. Option c is incorrect because while a thin bright wall outlines the sinus, the cavity itself is not a white solid; its interior is the dark air space, not a filled radiopaque structure.

Correct Answer: the articular disc

Clicking often involves the articular disc, but the disc is soft tissue and does not show on plain radiography, so CBCT or arthrography is required to assess it. Option a is incorrect because the mandibular condyle is dense bone that shows clearly on a panoramic, so it is not the hidden structure; it can be evaluated on plain film without trouble. Option b is incorrect because the glenoid fossa is the bony socket of the temporal bone and is visible on the image, making it a structure that plain radiography can in fact display. Option d is incorrect because the coronoid process is a bony projection of the ramus that appears on some views; being bone, it registers on plain film rather than escaping it like the disc.

Correct Answer: same lingual, opposite buccal

SLOB means same lingual, opposite buccal. When the tube is shifted, an object moving the same way as the beam lies lingual, and one moving the opposite way lies buccal. Option a is incorrect because straight lingual, opposite base is not the phrase; the second word must be buccal, since the rule contrasts the lingual and buccal sides, not a base. Option c is incorrect because side lingual, outer bone misstates the rule; the memory aid pairs lingual with same and buccal with opposite, not vague terms like side and outer bone. Option d is incorrect because set level of bone has nothing to do with the rule; SLOB is about left-right object movement with a tube shift, not about measuring bone height.

Correct Answer: buccal side

By the rule, opposite means buccal; an object that appears to move against the direction of the tube shift sits on the buccal or facial side, away from the tongue. Option b is incorrect because the lingual side is where an object moving the same direction as the tube ends up, so a structure moving opposite the shift is the buccal one, not the lingual. Option c is incorrect because the occlusal plane is the biting surface level, not a buccal or lingual position, so it does not answer where a shifting object lies side to side. Option d is incorrect because midline only describes a front-to-back center position; SLOB resolves buccal versus lingual location, so the midline is not what the rule determines here.

Correct Answer: occlusal projection

The occlusal, or right-angle, projection is the source-listed view for locating retained roots, impacted teeth, salivary stones, and fractures over a broad section of an arch. Option a is incorrect because a bitewing is built for interproximal caries and crestal bone on a few teeth; its small field is not the projection named for locating retained roots in the bone. Option b is incorrect because the panoramic surveys broadly and helps spot impactions, but the specific source-listed localization view for retained roots and impacted teeth is the occlusal, not the panoramic alone. Option d is incorrect because a cephalometric is an extraoral orthodontic projection of the skull profile; it is not used to pinpoint retained roots or impactions within the dental arch.

Correct Answer: CBCT

A two-dimensional image flattens depth and cannot reveal buccal versus lingual position, so CBCT, which reconstructs the area in three dimensions, is used for true localization such as mapping an impaction to the nerve. Option a is incorrect because a faster receptor changes only the dose or exposure needed; speed adds no depth information, so it cannot reveal the buccolingual position a flat image lacks. Option b is incorrect because a single bitewing is itself a flat two-dimensional image, so it shares the very limitation in question and cannot provide three-dimensional localization. Option c is incorrect because brighter lighting improves how an existing image is viewed but adds no new spatial data; it cannot recover the depth a two-dimensional projection never captured.

Correct Answer: ghost image

A ghost image is an artifact from a dense object such as an earring; it projects to the opposite side, higher, blurred, and magnified, and is prevented by removing all metal before exposure. Option a is incorrect because a true foreign body embedded in bone appears sharp and stays on its actual side; it does not jump to the opposite side, enlarge, and blur the way a ghost image does. Option c is incorrect because the maxillary sinus is a radiolucent air space, not a radiopaque object, so a bright, displaced, magnified shape cannot be explained by normal sinus anatomy. Option d is incorrect because a processing stain is a flat surface mark with no real density behind it; it would not show the magnification, blurring, and opposite-side projection typical of a ghost image.