Free DANB RHS Practice Test: 75 Questions With Answers

Correct answer: D. The mental foramen superimposed over the apex

The mental foramen shows up as a small round or oval radiolucency in the apical region of the mandibular premolars, so it can look like disease at the root tip. An unbroken lamina dura around the apex points to normal anatomy; periapical lesions are typically associated with loss of the lamina dura. The maxillary sinus is in the upper jaw, and interproximal decay sits on the crown, not at the apex.

Sources: DE 115: Dental Radiography (open textbook), 28.3 Bony landmarks of the mandible — Mental foramen; Al-Mustaqbal University lecture — Caries, periodontal and periapical lesions on radiographs — Periapical lesions (loss of lamina dura)

Correct answer: B. Genial tubercles surrounding the lingual foramen

Near the midline on the lingual of the mandible, the genial tubercles appear as a radiopaque ring and the lingual foramen as a small radiolucent dot inside it, just below the incisor apices. The incisive foramen and nasal septum are maxillary landmarks. The mental ridge is a thick radiopaque band running from the premolar region toward the midline, and the mental fossa is a radiolucent area above it.

Source: DE 115: Dental Radiography (open textbook), 28.3 Bony landmarks of the mandible — Genial tubercles; lingual foramen; mental ridge

Correct answer: C. The maxillary sinus, crossed by septa

The maxillary sinus appears as a radiolucent area above the apices of the maxillary premolars and molars. Its floor is dense cortical bone, and bony septa within the sinus show as radiopaque lines. The nasal cavity sits above the maxillary incisors, and the mandibular canal is in the lower jaw.

Source: DE 115: Dental Radiography (open textbook), 28.2 Bony landmarks of the maxilla — Maxillary sinus; septa within the maxillary sinus

Correct answer: B. Incisive (nasopalatine) foramen

The incisive foramen, where the nasopalatine nerve exits the maxilla, appears as a small oval or round radiolucency between the roots of the maxillary central incisors. The lingual and mental foramina are mandibular landmarks. The lateral fossa appears as a radiolucent area between the maxillary canine and lateral incisor.

Source: DE 115: Dental Radiography (open textbook), 28.2 Bony landmarks of the maxilla — Incisive foramen; lateral fossa

Correct answer: A. A thin radiolucent periodontal ligament space bordered by a continuous radiopaque lamina dura

In healthy teeth the lamina dura appears as a dense radiopaque line lining the socket, and the periodontal ligament space appears as a thin radiolucent line between the root and the lamina dura. Reversing those appearances is wrong, and a widened space with missing lamina dura is a change the dentist would want to evaluate.

Source: DE 115: Dental Radiography (open textbook), 34.1 Periodontal disease on images — Lamina dura; periodontal ligament space

Correct answer: C. Horizontal bone loss

Horizontal bone loss occurs in a plane parallel to the CEJs of adjacent teeth. Vertical bone loss does not follow that plane and is more severe on one tooth's side than the neighbor's. Furcation involvement is a radiolucency where bone between the roots of a multirooted tooth is lost. Bone that has dropped away from its normal level is not normal crestal bone.

Source: DE 115: Dental Radiography (open textbook), 34.3 Bone loss — Bone loss: horizontal vs vertical; furcation

Correct answer: C. As a possible periapical lesion (such as a granuloma, cyst or abscess) for the dentist to diagnose

A radiolucency at the apex with loss of lamina dura is the classic appearance of periapical inflammatory lesions such as a granuloma, cyst or abscess. The assistant's job is to recognize the finding and make sure the dentist sees it; diagnosis belongs to the dentist. Normal PDL space is a thin line with intact lamina dura, a localized finding at one apex is not a reason for an automatic retake, and the area described is radiolucent, not radiopaque.

Sources: Al-Mustaqbal University lecture — Caries, periodontal and periapical lesions on radiographs — Periapical inflammatory lesions; DANB RHS Exam Outline and References (effective 03/12/2025) — Domain I.A.1 apical pathology; radiography terms (abscess/cyst/granuloma)

Correct answer: D. As a radiolucent (dark) area in the tooth structure

Decay removes mineral, so x-rays pass through the affected tooth structure more easily and the lesion appears radiolucent (dark). Radiopaque areas resist the beam and appear light, which describes restorations and dense structures, not caries. A uniform gray across the whole image points to an exposure setting problem, not decay.

Sources: Al-Mustaqbal University lecture — Caries, periodontal and periapical lesions on radiographs — Dental caries: radiolucent zones; DE 115: Dental Radiography (open textbook), 6.1 Image characteristics — Radiolucent defined

Correct answer: B. Composite ranges from radiolucent to slightly radiopaque depending on its composition

Composite restorations vary from radiolucent to slightly radiopaque depending on their composition, so a darker composite is not automatically decay; the dentist compares the image with the clinical exam. Composite is not more radiopaque than amalgam, which appears completely radiopaque, and exposure does not change over a single tooth on one receptor.

Source: DE 115: Dental Radiography (open textbook), 32.1 Restorations and dental materials — Composite restorations

Correct answer: A. A gold crown

Gold restorations appear completely radiopaque and, unlike amalgam, show a smooth marginal outline. Porcelain is only slightly radiopaque, resembling dentin, and composite ranges from radiolucent to slightly radiopaque. Stainless steel crowns are radiopaque but not as dense as gold or amalgam, and option D describes margins that do not match this image.

Source: DE 115: Dental Radiography (open textbook), 32.1 Restorations and dental materials — Gold restorations; stainless steel and chrome crowns; porcelain

Correct answer: A. Gutta-percha

Gutta-percha fills pulp canals and appears radiopaque, but less radiodense than metallic restorations. Silver points are very radiopaque, like other metals, and appear denser than gutta-percha; a metal file fragment would also be metal-dense. Empty canals would appear radiolucent.

Source: DE 115: Dental Radiography (open textbook), 32.1 Restorations and dental materials — Materials used in endodontics

Correct answer: D. A dental implant

Implants appear radiopaque within the bone, and their exact appearance depends on the implant's shape and design. A retained root tip has tooth density and canal anatomy, a torus is a bony outgrowth on the lingual of the mandible, and an amalgam fragment is a small irregular radiopacity in soft tissue rather than a post supporting a crown.

Sources: DE 115: Dental Radiography (open textbook), 32.1 Restorations and dental materials — Materials used in oral surgery: implants; DANB RHS Exam Outline and References (effective 03/12/2025) — Domain I.A.4 dental implants

Correct answer: B. A maxillary occlusal (topographic) projection

The occlusal technique is used when large areas of the maxilla or mandible must be seen; the maxillary topographic projection examines the palate and anterior maxillary teeth. A bitewing shows crowns and crestal bone, a single periapical covers a few teeth, and a cephalometric projection is an extraoral skull image.

Source: DE 115: Dental Radiography (open textbook), 23.1 Occlusal technique — Purpose and use; maxillary occlusal projections

Correct answer: A. Detecting caries, periodontal disease or periapical disease

Extraoral images are used to evaluate large areas of the skull or jaws, growth and development, impacted teeth, large lesions, trauma and the TMJ area. They are not used to detect caries, periodontal disease or periapical disease; intraoral bitewings and periapicals show that detail.

Source: DE 115: Dental Radiography (open textbook), 26.1 Extraoral imaging — Purpose and use of extraoral imaging

Correct answer: D. Orthodontics and oral surgery

Skull imaging examines the bones of the face and skull and is most often used in oral surgery and orthodontics; the lateral cephalometric projection is the most common skull image. Canal length, caries and periodontal status call for intraoral images and clinical examination.

Source: DE 115: Dental Radiography (open textbook), 26.2 Extraoral projections — Skull imaging; lateral cephalometric projection

Correct answer: B. The smallest field of view needed for the area of interest

The 2024 recommendations say to use the smallest field of view necessary for the specific anatomical area and to optimize technique factors for the lowest dose that still gives a diagnostically acceptable image. CBCT dose varies with the field of view and settings, which is why a larger-than-needed field adds exposure without benefit.

Sources: ADA/AAOMR 2026 patient-selection recommendations (open full text) — Table 1, CBCT: smallest field of view consistent with needed information; Benavides E, et al. Optimizing radiation safety in dentistry. JADA 2024;155(4):280-293 — Recommendations 3.2.1–3.2.3

Correct answer: B. Make a good-faith attempt to obtain the previous radiographs

The ADA/AAOMR's 2026 patient-selection recommendations say previously obtained images should be reviewed and that imaging decisions should account for prior radiographs. Retaking images simply to create a local copy can add exposure without diagnostic benefit, and a patient's memory is not a substitute for the images.

Sources: ADA/AAOMR 2026 patient-selection recommendations (open full text) — General recommendations and Discussion: review/retrieve previously obtained images; ADA — X-Rays/Radiographs — Patient selection / good-faith attempt to use previous radiographs

Correct answer: C. Proper density and contrast, sharp outlines, and minimal distortion

A diagnostically acceptable image has appropriate density and contrast, sharp detail, and minimal distortion for the area being examined. An intentionally elongated image is distorted, and an overly dark image can lose useful detail. Maximum black-and-white contrast is not automatically the best diagnostic image.

Source: DE 115: Dental Radiography (open textbook), 6.1 Image characteristics — Diagnostic radiograph; density and contrast

Correct answer: D. Have the patient remove the eyeglasses and any facial jewelry in the beam path before exposing

For intraoral imaging, patients should remove facial jewelry in the beam path (such as nose rings or large earrings), eyeglasses and intraoral prostheses before exposure; metal left in the path can superimpose over the teeth. Waiting to see whether it shows up risks a retake, which means extra exposure.

Source: Dentalcare CE 589 — Intraoral patient preparation — Intraoral patient preparation

Correct answer: D. A ghost image of the earring

A ghost image resembles the real object but appears on the opposite side of the image and higher, and it is blurred and magnified. It forms when a radiodense object outside the focal trough is penetrated twice by the beam. The fix is to have the patient remove all radiodense objects from the head and neck before exposure.

Sources: Dentalcare CE 533 — Causes and appearance of panoramic errors (Table 5) — Table 5, error 1: ghost images; Dentalcare CE 533 — Panoramic patient preparation — Patient preparation guidelines

Correct answer: A. The patient's head was turned, so the midsagittal plane was not centered

When the head is not centered, the ramus and posterior teeth are unequally magnified and contacts overlap. The correction is to keep the midsagittal plane perpendicular to the floor with the indicator light centered between the maxillary central incisors. Chin height, anterior–posterior position and tongue placement produce different, recognizable errors.

Source: Dentalcare CE 533 — Causes and appearance of panoramic errors (Table 5) — Table 5, error 8: head not centered

Correct answer: A. The patient was positioned too far forward, in front of the focal trough

With the patient too far forward, anterior teeth appear narrowed and the spine is visible; too far back makes the anterior teeth look magnified and may cut off the ramus. The correction is to make sure the teeth are in the bite-block notches. A low chin creates an exaggerated smile line, and open lips create a dark shadow around the anterior teeth.

Source: Dentalcare CE 533 — Causes and appearance of panoramic errors (Table 5) — Table 5, errors 6 and 7

Correct answer: B. The patient's chin was tipped too high

A chin tipped too high produces a reverse smile line, blurred and magnified maxillary incisors, and condyles that may drop off the image. A chin tipped too low does the opposite, creating an exaggerated smile. The correction for both is to keep the Frankfort plane parallel to the floor.

Source: Dentalcare CE 533 — Causes and appearance of panoramic errors (Table 5) — Table 5, errors 4 and 5

Correct answer: B. Have the patient stand as tall as possible, or seat the patient upright if needed

When the spine is not straight, the cervical spine shows as a radiopacity in the center of the image. The patient should stand as tall as possible, or be seated if necessary and reminded to sit upright. Chin tilt and head rotation cause different errors, and raising the exposure settings does not remove a superimposed spine.

Source: Dentalcare CE 533 — Causes and appearance of panoramic errors (Table 5) — Table 5, error 9; seated patients

Correct answer: A. Close your lips around the bite block

When the lips are not closed around the bite block, a dark radiolucent shadow appears around the anterior teeth. Keeping the tongue on the floor of the mouth causes a different error, a radiolucent band over the maxillary apices; the tongue belongs against the palate. Lowering the chin or stepping back creates other positioning errors.

Source: Dentalcare CE 533 — Causes and appearance of panoramic errors (Table 5) — Table 5, error 3; tongue against the hard palate

Correct answer: B. Between the tori and the tongue

With mandibular tori, the receptor is placed between the tori and the tongue, not on the tori, and then exposed. Resting the receptor on a torus tips it and causes discomfort, and a buccal placement does not image the teeth correctly. Tori call for a modification, not abandoning the image.

Source: DE 115: Dental Radiography (open textbook), 19.3 Paralleling technique modifications — Modifications in paralleling technique: bony growths

Correct answer: C. On the far side of the torus, not resting on it

For a maxillary torus, the receptor is placed on the far side of the torus and then exposed, rather than resting on it. Placing it on the torus tips the receptor out of parallel with the teeth. A bitewing does not show the root apices, so it cannot replace a periapical.

Source: DE 115: Dental Radiography (open textbook), 19.3 Paralleling technique modifications — Modifications in paralleling technique: maxillary torus

Correct answer: A. Red

In the Rinn XCP system, red instruments are used for bitewings, blue for anterior periapicals, and yellow for posterior periapicals. Other brands may use different colors, so follow the system your office uses.

Source: Indian Health Service, Dental Digital Imaging — Chapter 1: Radiation Safety and Protection — Positioning devices: Rinn XCP color code

Correct answer: B. Reduce the exposure setting, such as time or mA, following the technique chart

Images that are too dark have too much exposure. Raising kilovoltage increases density (the image gets darker), and increasing time or mA adds more x-rays, so the fix is to lower the exposure setting according to the office's technique chart for that receptor and patient size. Repeating the same setting reproduces the error and adds exposure.

Sources: DE 115: Dental Radiography (open textbook), 5.1 Radiation characteristics — Density and kilovoltage peak; DE 115: Dental Radiography (open textbook), Chapter 5: Radiation characteristics — Milliamperage, exposure time and density; Benavides E, et al. Optimizing radiation safety in dentistry. JADA 2024;155(4):280-293 — Recommendation 4.2: technique charts

Correct answer: D. On the viewer's left, as if facing the patient

With labial mounting, images are viewed as if the viewer is facing the patient, so the patient's right appears on the viewer's left. Lingual mounting views them as if from inside the mouth looking out. The method, not the sensor brand, determines orientation.

Source: DE 115: Dental Radiography (open textbook), 11.2 Image mounting methods — Labial and lingual mounting

Correct answer: B. Permanent mandibular right first molar

Universal numbers run from #1, the maxillary right third molar, across to #16, then from #17, the mandibular left third molar, around to #32, the mandibular right third molar. #30 is the mandibular right first molar; the mandibular left first molar is #19, the maxillary right first molar is #3, and the mandibular right second molar is #31.

Sources: ADA Universal Tooth Designation System (HL7 code system listing) — Universal designations 1, 16, 17, 30, 31, 32; Radiopaedia — American Dental Association Universal Numbering System — Full list by quadrant

Correct answer: D. #14

Counting from #9 (maxillary left central incisor) back through the left side gives #12 and #13 for the premolars and #14 for the first molar. #3 is the maxillary right first molar, #19 is the mandibular left first molar, and #15 is the maxillary left second molar.

Source: Radiopaedia — American Dental Association Universal Numbering System — Left maxillary 9–16

Correct answer: D. Keep the originals and provide copies; an unpaid balance is not a reason to refuse

The dentist owns the physical record, including radiographs, and is its legal guardian, so originals stay with the practice. HIPAA, and possibly state law, still requires providing patients copies of their records even when the account is unpaid; a reasonable, cost-based copying fee may be charged. State rules can add details such as deadlines.

Source: ADA — Ownership of Dental Records and Radiographs — Ownership; copies even if the account is unpaid

Correct answer: C. No; disclosure to another provider for that provider's treatment of the patient is permitted without authorization

HHS states that the Privacy Rule permits a provider to disclose protected health information, without the individual's authorization, to another health care provider for that provider's treatment of the individual (45 CFR 164.506). Reasonable safeguards still apply, and some offices choose stricter internal policies.

Source: HHS HIPAA FAQ 271 — Sending records to another treating provider — FAQ 271

Correct answer: A. Images are taken only when the dentist orders them based on the patient's needs

Imaging is not ordered just because a calendar interval has elapsed. The ADA/AAOMR's 2026 recommendations say the decision should follow the clinical examination and be based on medical and dental history, disease risk, clinical findings and previously obtained images. The treating dentist decides whether imaging is clinically justified.

Sources: ADA/AAOMR 2026 patient-selection recommendations (open full text) — Box 1, General Recommendation 1.2; ADA — X-Rays/Radiographs — Patient Selection for Dental Radiographic Examinations

Correct answer: D. Seat the patient if the unit allows it, and remind them to sit as upright as possible

Some panoramic units allow the patient to sit. A seated patient should be reminded to sit upright, because slumping superimposes the spine over the anterior teeth. Staying beside the patient to hold them puts the operator in the radiation area, and leaning or skipping positioning checks produces errors and retakes.

Sources: Dentalcare CE 533 — Causes and appearance of panoramic errors (Table 5) — Patients with difficulty maintaining position; Indian Health Service, Dental Digital Imaging — Chapter 1: Radiation Safety and Protection — Protection of the operator

Correct answer: C. Paralleling

The paralleling technique most accurately represents the level of bone. With the bisecting technique, the vertical angulation can distort how high or low the bone appears, which matters when evaluating periodontal bone loss.

Source: DE 115: Dental Radiography (open textbook), 34.1 Periodontal disease on images — Paralleling vs bisecting and bone level

Correct answer: D. Short-wavelength, high-energy x-rays

Wavelength determines the energy and penetrating power of radiation, and shorter wavelengths penetrate more. Long-wavelength, low-energy x-rays are the ones the filter removes because they add patient dose without contributing to the image.

Sources: DE 115: Dental Radiography (open textbook), 5.1 Radiation characteristics — X-ray beam quality; wavelength; DE 115: Dental Radiography (open textbook), 4.1 Radiation protection — Added filtration

Correct answer: B. It becomes darker, with lower contrast (more shades of gray)

Increasing kilovoltage produces a higher-energy beam, so the image shows increased density (darker) and lower contrast, with many shades of gray. Low kilovoltage settings produce high contrast.

Source: DE 115: Dental Radiography (open textbook), 5.1 Radiation characteristics — Density and contrast with kilovoltage peak

Correct answer: B. It drops to one-fourth

Under the inverse square law, intensity is inversely proportional to the square of the distance from the source. Doubling the distance spreads the same x-rays over four times the area, so intensity falls to 1/2², or one-fourth.

Sources: Al-Mustaqbal University lecture — Inverse square law — Theory: doubling distance reduces intensity to one-fourth; DE 115: Dental Radiography (open textbook), Chapter 5: Radiation characteristics — Inverse square law (learning objective 5.2)

Correct answer: D. Absorbs longer-wavelength, low-energy x-rays, leaving a more penetrating beam

Added filtration is an aluminum disk between the collimator and the tubehead seal that filters out longer-wavelength, lower-energy x-rays, producing a higher-energy, more penetrating useful beam. Shaping the beam is collimation, and filtration does not increase x-ray production or protect the operator from scatter.

Source: DE 115: Dental Radiography (open textbook), 4.1 Radiation protection — Inherent, added and total filtration

Correct answer: A. It restricts the beam to about the size and shape of the receptor, so less tissue is exposed

Collimation restricts the size and shape of the beam. Rectangular collimation limits exposure to little more than the receptor area, and the ADA's 2024 review notes that collimating to the region of interest consistently reduces dose by more than 40%. Removing low-energy x-rays is filtration's job.

Sources: Benavides E, et al. Optimizing radiation safety in dentistry. JADA 2024;155(4):280-293 — Dose reduction and optimization; recommendation 3.1.2; DE 115: Dental Radiography (open textbook), 4.1 Radiation protection — Collimation

Correct answer: C. It produces less divergence of the x-ray beam

A longer PID increases the distance between the source and the patient's skin, so the beam diverges less and a smaller volume of tissue is irradiated. The ADA's 2024 review lists long PIDs among the measures that substantially reduce exposure.

Sources: DE 115: Dental Radiography (open textbook), 4.1 Radiation protection — PID length and beam divergence; Benavides E, et al. Optimizing radiation safety in dentistry. JADA 2024;155(4):280-293 — Dose reduction and optimization

Correct answer: C. 20 cm

Recommendation 3.1.3 says the intraoral system shall be configured so the distance from the focal spot to the skin entrance surface is not less than 20 cm. The same recommendations call for operating intraoral units between 60 and 80 kV. Two meters is the operator distance when no barrier is available, not a source-to-skin distance.

Source: Benavides E, et al. Optimizing radiation safety in dentistry. JADA 2024;155(4):280-293 — Box 2, recommendations 3.1.3, 3.1.4 and 2.0.1

Correct answer: A. Gray (Gy); the traditional unit is the rad

Absorbed dose is measured in rad and gray (Gy). The roentgen and coulombs per kilogram measure exposure in air, and the rem and sievert measure dose equivalent, which accounts for the biological effect of the type of radiation.

Source: U.S. NRC — Measuring Radiation — R-E-A-D: exposure, absorbed dose, dose equivalent

Correct answer: D. Roentgen (R) and coulombs per kilogram (C/kg)

Exposure, the amount of radiation traveling through air, is measured in roentgens and coulombs per kilogram. Gray and rad measure absorbed dose, sievert and rem measure dose equivalent, and becquerel and curie measure the radioactivity of a material.

Source: U.S. NRC — Measuring Radiation — R-E-A-D units

Correct answer: C. Using digital receptors, rectangular collimation and careful technique to avoid retakes

ALARA means getting the clinical benefit at the lowest reasonably achievable dose. The ADA's 2024 priority recommendations include digital receptors and rectangular collimation, and good technique avoids retakes, which add exposure for patient and operator. Routine or cosmetic retakes and calendar-based series do not meet that standard.

Sources: Benavides E, et al. Optimizing radiation safety in dentistry. JADA 2024;155(4):280-293 — ALARA; Box 1 priority recommendations; Indian Health Service, Dental Digital Imaging — Chapter 1: Radiation Safety and Protection — Use good technique to reduce retakes

Correct answer: A. Latent period

After exposure, the sequence is the latent period (the time before effects appear), the period of injury, and the recovery period, during which some cellular repair occurs. The half-value layer is a measure of beam quality, not a biological period.

Source: Al-Mustaqbal University lecture — Biological radiation hazards — Radiation injury: latent period, period of injury, recovery period

Correct answer: A. A genetic effect

Genetic effects are not seen in the irradiated person but can be passed on to future generations. Somatic effects appear in the person who was exposed. Tissue reactions and acute radiation syndrome follow high doses well above anything used in dental imaging.

Sources: Al-Mustaqbal University lecture — Biological radiation hazards — Somatic and genetic effects; Benavides E, et al. Optimizing radiation safety in dentistry. JADA 2024;155(4):280-293 — Tissue reactions vs stochastic effects

Correct answer: B. Dental doses are usually well below the threshold for tissue reactions, but cumulative low-dose exposure still warrants minimizing dose

The review explains that tissue reactions such as skin burns or cataracts follow acute exposures above roughly 100 mGy, and dental imaging is typically well below that. Because patients receive many examinations over a lifetime and low-dose exposure may carry stochastic (random) risk, exposure is still kept as low as reasonably achievable.

Source: Benavides E, et al. Optimizing radiation safety in dentistry. JADA 2024;155(4):280-293 — Radiation exposure and use of ionizing radiation in dentistry

Correct answer: C. Children have higher organ radiosensitivity and a longer expected lifespan for effects to accumulate

Children and young adults are more susceptible because of higher organ sensitivity and a longer expected lifespan, which allows a greater cumulative effect. The recommendations call for justified imaging, settings optimized for size and age, and careful positioning with rectangular collimation, not routine thyroid collars.

Source: Benavides E, et al. Optimizing radiation safety in dentistry. JADA 2024;155(4):280-293 — Special considerations for pediatric patients; recommendations 3.0.4 and 3.3.1

Correct answer: B. The ADA no longer recommends routine abdominal or thyroid shielding; it can block the beam, and dose is reduced through rectangular collimation, positioning and justified imaging

The 2024 recommendations say abdominal and thyroid shielding during intraoral, panoramic, cephalometric and CBCT imaging is no longer recommended for pediatric or adult patients. Shields can block the primary beam and cause retakes, and they do not protect against internal scatter. Digital imaging still uses x-rays. If a state rule still requires shielding, the office follows that rule.

Sources: Benavides E, et al. Optimizing radiation safety in dentistry. JADA 2024;155(4):280-293 — Patient protection and shielding; recommendation 3.0.5; ADA — Updated recommendations to enhance radiography safety in dentistry (Feb 1, 2024) — Press release

Correct answer: A. Take the justified image with normal dose-reduction measures; the shielding recommendation applies to pregnant patients too

Imaging decisions rest on the dentist's judgment of clinical benefit. The ADA noted that its 2024 recommendation to discontinue lead aprons and thyroid collars applies to all patients, including those who are pregnant; dose is minimized with rectangular collimation, digital receptors and good positioning. Follow any state rule that adds requirements.

Sources: ADA — Updated recommendations to enhance radiography safety in dentistry (Feb. 1, 2024) — Shielding recommendation applies regardless of age or health status, including pregnancy; Benavides E, et al. Optimizing radiation safety in dentistry. JADA 2024;155(4):280-293 — Recommendations 3.0.2 and 3.0.5

Correct answer: D. Document the discussion and the patient's refusal in the patient record

Patients may refuse recommended care, including a radiograph. ADA guidance says the dentist should explain the recommendation and potential consequences, then document the refusal and discussion in the record. Whether treatment can safely proceed without the image is the dentist's decision.

Sources: ADA — Informed Consent Refusal — Patient right to refuse; document the discussion and refusal; ADA — Types of Consent — Document informed refusal in the patient record

Correct answer: D. Do not hold the tubehead or PID; report the drift so the arm can be adjusted or repaired

A drifting tubehead signals that a mechanical adjustment or repair is needed, and it should be reported right away. Neither the operator nor the patient should hold the tubehead or PID during exposure, because a small potential for leakage radiation exists. A drifting tubehead causes blurred images and retakes.

Source: Indian Health Service, Dental Digital Imaging — Chapter 1: Radiation Safety and Protection — Don't hold the X-ray head or the PID

Correct answer: C. Follow the facility's radiation safety program, use protective barriers and wear a personal dosimeter regardless of anticipated exposure

Recommendation 2.1.2 says pregnant personnel who operate imaging equipment shall follow the facility's radiation safety program, including limiting occupational exposure, using protective barriers and wearing personal dosimeters regardless of anticipated exposure levels. The 1 mSv threshold applies to other staff deciding whether to wear dosimeters. No operator should hold receptors for patients.

Sources: Benavides E, et al. Optimizing radiation safety in dentistry. JADA 2024;155(4):280-293 — Box 2, recommendations 2.1.1 and 2.1.2; Indian Health Service, Dental Digital Imaging — Chapter 1: Radiation Safety and Protection — Never hold a receptor for a patient

Correct answer: C. Immediately before putting on gloves and again right after removing them

Wearing gloves does not eliminate the need for hand hygiene. CDC says to perform hand hygiene immediately before donning gloves and to wash hands immediately after glove removal, because gloves can have small defects and hands can be contaminated while removing them. OSHA also requires hand washing as soon as feasible after removing gloves.

Sources: CDC, Guidelines for Infection Control in Dental Health-Care Settings — 2003 (MMWR 52/RR-17) — Gloves and gloving; 29 CFR 1910.1030, Bloodborne Pathogens (eCFR text via Cornell LII) — (d)(2)(v)

Correct answer: A. As other potentially infectious material (OPIM)

OSHA's definition of other potentially infectious materials specifically includes saliva in dental procedures. That is why placing receptors, which involves contact with saliva and mucous membranes, calls for standard precautions and gloves. Whether an item is regulated waste depends on how much material it would release, not on saliva contact alone.

Sources: 29 CFR 1910.1030, Bloodborne Pathogens (eCFR text via Cornell LII) — (b) Definitions: OPIM; regulated waste; CDC, Guidelines for Infection Control in Dental Health-Care Settings — 2003 (MMWR 52/RR-17) — Background: standard precautions

Correct answer: C. Discarded after that patient; they are changed between patients and never washed for reuse

Medical gloves are single-use items used for one patient and then discarded, and they should be changed between patients and when torn or punctured. OSHA prohibits washing or decontaminating disposable gloves for reuse, and all PPE is removed before leaving the work area.

Sources: CDC, Guidelines for Infection Control in Dental Health-Care Settings — 2003 (MMWR 52/RR-17) — Gloves and gloving; 29 CFR 1910.1030, Bloodborne Pathogens (eCFR text via Cornell LII) — (d)(3)(ix)(A)–(B); (d)(3)(vii)

Correct answer: B. Whenever splashes, spray, spatter or droplets of blood or OPIM may be generated

OSHA requires masks combined with eye protection, such as goggles or glasses with solid side shields, or chin-length face shields, whenever splashes, spray, spatter or droplets of blood or OPIM may be generated. A coughing or gagging patient during receptor placement is a realistic example. Standard precautions apply to every patient, not only those with a known infection.

Source: 29 CFR 1910.1030, Bloodborne Pathogens (eCFR text via Cornell LII) — (d)(3)(x)

Correct answer: D. Gown, mask, eyewear, gloves

CDC's sequence for putting on PPE is gown, then mask or respirator, then goggles or face shield, then gloves, which go on last so they extend over the gown's wrists. Removal follows a different order, starting with the most contaminated items.

Source: CDC — Sequence for Putting On and Removing PPE — Sequence for putting on PPE

Correct answer: B. It penetrates soft tissue or bone and must be sterilized

Critical items penetrate soft tissue or bone, carry the greatest risk of transmitting infection, and must be heat-sterilized. Semicritical items touch mucous membranes or nonintact skin, and noncritical items contact only intact skin. Most items used in routine intraoral imaging, such as receptor holders, are semicritical.

Source: CDC, Guidelines for Infection Control in Dental Health-Care Settings — 2003 (MMWR 52/RR-17) — Sterilization and disinfection of patient-care items

Correct answer: A. High-level disinfection, with heat-tolerant or disposable alternatives preferred

Semicritical items should be heat-sterilized when they tolerate heat; if one is heat-sensitive, it should at minimum receive high-level disinfection, and CDC prefers heat-tolerant or disposable alternatives. Digital sensors are a special case: when they cannot tolerate sterilization or high-level disinfection, CDC calls for an FDA-cleared barrier plus cleaning and disinfection as the manufacturer directs.

Sources: CDC, Guidelines for Infection Control in Dental Health-Care Settings — 2003 (MMWR 52/RR-17) — Sterilization and disinfection of patient-care items; CDC — Summary of Infection Prevention Practices: Sterilization and Disinfection — Digital radiography sensors

Correct answer: C. Barrier-protect them and change the barrier between patients, or clean and disinfect them between patients

Surfaces touched with contaminated gloves become contaminated even though they never touch the patient. CDC notes that disposable barrier protection may be preferable for surfaces that are hard to clean, and contaminated surfaces need cleaning and disinfection with an EPA-registered hospital disinfectant. OSHA requires protective coverings to be replaced when contaminated.

Sources: CDC, Guidelines for Infection Control in Dental Health-Care Settings — 2003 (MMWR 52/RR-17) — Noncritical items and barrier protection; 29 CFR 1910.1030, Bloodborne Pathogens (eCFR text via Cornell LII) — (d)(4)(ii)(A)–(B)

Correct answer: D. Remove contaminated barriers while still gloved, remove gloves, perform hand hygiene, then place fresh barriers

Contaminated barriers are handled with gloved hands, so they come off before the gloves. Hands are then washed after glove removal, and clean barriers go on with clean hands. Stacking new barriers over contaminated ones or leaving them in place until the end of the day defeats their purpose.

Sources: 29 CFR 1910.1030, Bloodborne Pathogens (eCFR text via Cornell LII) — (d)(2)(v); (d)(4)(ii)(B); CDC, Guidelines for Infection Control in Dental Health-Care Settings — 2003 (MMWR 52/RR-17) — Gloves and gloving

Correct answer: C. Used once and discarded

Disposable positioning devices are used once and disposed of. Heat-tolerant reusable positioning devices, by contrast, are cleaned, packaged and heat-sterilized between patients.

Source: Wisconsin DOC Dental Radiation Policy, Attachment C — Infection Control for Digital Radiography — Infection control for radiographic positioning devices

Correct answer: D. Clean and disinfect the sensor according to the manufacturer's instructions

Barriers reduce contamination but do not always prevent it, so the sensor is cleaned and disinfected after barrier removal and before use on another patient, using products the manufacturer approves. Most sensors cannot tolerate heat sterilization, and plain water is not disinfection.

Sources: Wisconsin DOC Dental Radiation Policy, Attachment C — Infection Control for Digital Radiography — General considerations; infection control for sensors; CDC — Summary of Infection Prevention Practices: Sterilization and Disinfection — Digital radiography sensors

Correct answer: A. Clean barriers over the parts the patient will touch and a sterile or disposable bite block

Panoramic unit preparation includes placing clean barriers over components that will contact the patient and inserting a sterile bite block (or a disposable one), in addition to setting exposure factors. A bite block contacts the mouth, so a visually clean used one is not acceptable.

Source: Dentalcare CE 589 — Steps in the panoramic imaging procedure — Unit preparation

Correct answer: B. Wipe them with disinfectant

Infection control steps must be completed before an extraoral exposure, and when a unit with a cephalostat is used, the ear rods must be wiped with disinfectant between patients because they contact each patient's head.

Source: DE 115: Dental Radiography (open textbook), 26.1 Extraoral imaging — Step-by-step procedures

Correct answer: C. Hand hygiene

CDC describes hand hygiene as the single most critical measure for reducing the risk of transmitting organisms to patients and health care personnel. Masks, barriers and gowns are important, but they work alongside hand hygiene rather than replacing it.

Source: CDC, Guidelines for Infection Control in Dental Health-Care Settings — 2003 (MMWR 52/RR-17) — Hand hygiene

Correct answer: C. The mode of transmission

Infection requires a pathogen, a reservoir, a mode of transmission, a portal of entry and a susceptible host. A barrier blocks transfer of saliva from one patient to the next by indirect contact, which is the mode of transmission. Vaccination, by contrast, works on the susceptible host.

Source: CDC, Guidelines for Infection Control in Dental Health-Care Settings — 2003 (MMWR 52/RR-17) — Background: chain of infection; routes of transmission

Correct answer: B. Remove all PPE before leaving the work area

OSHA requires all personal protective equipment to be removed before leaving the work area and placed in a designated area or container. Hands are washed after glove removal. Carrying contaminated PPE into clean areas spreads contamination.

Source: 29 CFR 1910.1030, Bloodborne Pathogens (eCFR text via Cornell LII) — (d)(3)(vii)–(viii); (d)(2)(v)

Correct answer: A. Tuberculocidal

CDC defines an intermediate-level disinfectant as a liquid chemical germicide registered with EPA as a hospital disinfectant with a label claim of potency as tuberculocidal. It inactivates mycobacteria and most viruses and fungi but not bacterial spores. Sporicidal chemicals are sterilants or high-level disinfectants.

Source: CDC, Guidelines for Infection Control in Dental Health-Care Settings — 2003 (MMWR 52/RR-17) — Selected definitions: intermediate-level disinfectant

Correct answer: B. An EPA-registered tuberculocidal disinfectant

OSHA requires contaminated work surfaces to be decontaminated with an appropriate disinfectant. OSHA guidance lists EPA-registered tuberculocidal products among the accepted choices, along with certain other EPA-registered products, diluted bleach solutions, and FDA-cleared sterilants/high-level disinfectants when used for their labeled purpose. Plain soap, sterile water and hand rub are not substitutes for an appropriate surface disinfectant.

Sources: OSHA — Hospitals eTool: Biological Hazards, Appropriate disinfectants — Appropriate disinfectants under 29 CFR 1910.1030(d)(4)(ii)(A); OSHA — Bloodborne Pathogens Standard, 29 CFR 1910.1030 — 1910.1030(d)(4)(ii)(A)

Correct answer: A. Steam autoclaving or fully immersing the sensor

Digital radiography sensors are semicritical devices, but reprocessing capability varies by manufacturer. CDC says to follow the manufacturer’s instructions; if a sensor cannot tolerate heat sterilization or high-level disinfection, use an FDA-cleared barrier and then clean and disinfect it with an EPA-registered intermediate-level hospital disinfectant between patients. Do not autoclave or immerse a sensor unless its instructions specifically allow that method.

Source: CDC — Sterilization and Disinfection, Dental Infection Prevention and Control — Digital radiography sensors