How the practice questions are sourced

A source for every answer

A question goes into the bank only with a citation: the source, the section, and a verbatim passage that supports the answer. The passage stays in the bank as the evidence; each answer on this site names the source and section, so you can read it yourself.

Where a question turns out to be wrong, it is corrected in place and keeps its number. Write to the address in the footer if you find one.

The free questions here are a sample of at most a tenth of each exam’s bank, chosen across all of the exam’s domains. They cite U.S. government works only, so the sources are free to read; state rules, which differ from state to state, are left out.

The sources behind the free questions

Image credits

The photographs and drawings come from Wikimedia Commons and other open collections. Each is shown as Dentalingo uses it, resized for the web; where the app’s copy was cropped from the original, its credit says so. The author, licence and source sit beside each picture on its question page and again below.

• Intraoral periapical radiograph of three anterior teeth, crowns along the lower edge and roots running upward; a small white orientation marker sits in the bottom-left corner. In the bone between and above the roots, reaching past the level of the apices, lies a large ovoid dark area whose edges fade gradually into the surrounding bone, with a narrower dark tract running down beside one root. No restorations and no arrows, letters or other annotations are present. — Image: Shaimaa Abdellatif · CC BY-SA 4.0 · source
• Close-cropped periapical radiograph of three lower posterior teeth, crowns at the top and long roots running down; the left-hand crown carries a bright white restoration, and the area beside the upper two-thirds of the roots records dark, with a mottled speckled pattern appearing only lower down. — Image: Shaimaa Abdellatif · CC BY-SA 4.0 · source
• Periapical radiograph of a tilted third molar contacting the distal surface of the second molar — Image: Coronation Dental Specialty Group · CC BY-SA 3.0 · source
• Panoramic radiograph of a patient with no natural teeth in either jaw. Bright cast-metal appliances span both ridges, each carrying several short posts. Above the back part of the upper ridge a large dark space lies on each side, its lower edge marked by a fine bright line. — Image: Dentistxxx · CC BY-SA 3.0 · source
• Panoramic radiograph showing an impacted maxillary canine — Image: Challiyan · CC BY-SA 4.0 · source
• Wall-mounted intraoral dental x-ray unit with extension arm and round position indicating device — Image: Ptrump16 · CC BY-SA 4.0 · source
• Free-standing lead-lined protective screen on castors in a radiography room, with the exposure hand switch on a coiled cord hanging from its edge — Image: Adoscam · CC BY-SA 4.0 · source
• Close-up of a clip-on film badge dosimeter in its plastic case, with the internal metal filters and barcode visible through the housing — Image: Christoph Ziehr · CC BY-SA 4.0 · source
• Diagram of computed radiography workflow showing a storage phosphor plate being exposed, identified and read out by a laser scanner — Image: Leblans, P.; Vandenbroucke, D.; Willems, P · CC BY 3.0 · source
• Dental team member viewing mounted dental radiographs — Image: U.S. Navy photo by Photographer's Mate Airman Bernardo Fuller · Public domain · source
• Wall-mounted alcohol-based hand rub dispenser with an elbow-operated lever, mounted on a hand hygiene station board beside a step-by-step hand rub technique poster — Image: Enter · CC BY-SA 4.0 · source
• Hands being lathered with soap over a sink, rubbing the back of one hand with the palm of the other during routine hand washing — Image: Shixart1985 · CC BY 2.0 · source
• Saliva ejector suction tube positioned in a patient's mouth to remove fluids from the working field — Image: PeterEasthope · CC BY-SA 4.0 · source
• Clear plastic biohazard bag printed with the red biohazard symbol and the words Bio Hazard Bag for autoclaving and disposing of hazardous contaminated materials — Image: Nadina Wiorkiewicz (Nadine90) · CC BY-SA 3.0 · source
• Hands in heavy green utility gloves and a blue gown seating two metal dental handpieces onto the coupling spigots of a benchtop automated handpiece cleaning and lubrication unit with a numbered control panel, a stainless instrument bin behind — Image: U.S. Air Force photo by Senior Airman Tallon Bratton · Public domain · source
• Packaged dental instruments arranged in a sterilizer loading tray — Image: Bin im Garten · CC BY-SA 3.0 · source
• Roll of autoclave indicator tape in a dispenser beside a wrapped package with processed indicator tape — Image: Dakoman · CC BY 3.0 · source
• Benchtop ultrasonic cleaner with the lid open showing a perforated stainless steel instrument basket in the tank — Image: MHC Technology (image cropped) · CC BY-SA 4.0 · source
• Close-up of a chemical container label showing the GHS corrosion pictogram, the signal word Danger, a hazard statement and precautionary statements with first aid directions — Image: Petr Kadlec · CC BY-SA 4.0 · source
• Plumbed emergency eyewash and drench shower station with twin eyewash heads, a push-paddle activator, overhead shower head and green eyewash and safety shower signs — Image: Korn966 · CC BY-SA 4.0 · source
• Colour drawing of a single tooth cut through lengthways in its socket, with a greyed-out neighbour on each side. The crown has a wide chewing surface with rounded rises and a dip between them, capped by a thin striped outer layer; beneath it a large fan of fine lines fills the body of the tooth. Two separate roots run down into the bone, each holding a channel of red, blue and yellow strands that meet in a chamber under the crown. Eight plain leader lines run out to the right, none of them carrying any label. — Image: Ian Furst, Goran tek-en · CC BY-SA 3.0 · source
• Panoramic radiograph of a child's upper and lower jaws. Toward the back of each arch a broad tooth stands in the arch with a smaller crown forming in the bone directly beneath it; several of the teeth already in the mouth still have wide, open, unfinished root ends; and further crowns sit unerupted in the bone behind the last of the erupted ones. — Image: Coronation Dental Specialty Group · CC BY 3.0 · source
• Cross-section of a two-rooted molar in bone: a black channel of decay runs from the chewing surface through enamel and dentin into the discoloured pulp, and leader lines label Decay, Infected pulp and a pale rounded Abscess at one root tip, under the caption Infected Tooth. — Image: BruceBlaus (Blausen Medical) · CC BY 3.0 · source
• Close intraoral photograph with the lower lip drawn down by a finger, both front arches in frame with the teeth together. The upper incisors are pale and clean. Across the necks of the lower front teeth lies a thick yellow-brown build-up following the gumline, heaviest on the left of the frame. The gum is pale pink along most of its margin, with one small reddened area low on the left. No arrow, letter or marker appears. — Image: Roquex · CC0 1.0 · source
• Four double-ended stainless steel hand instruments lie parallel on a pale surface: one with a small angled flat blade at one end and a tiny ball at the other, one with a round ball at each end, one with short flat-faced cylindrical ends, and one with a broad flat paddle at one end and a long slim pointed blade at the other. — Image: Symposius · CC BY-SA 4.0 · source
• Macro photograph on a pale wooden surface of the far end of a hand scaler: a slim metal rod bends twice and finishes in a short flattened taper that rises to a fine sharp point, with the handle out of frame. — Image: DRosenbach · Public domain · source
• Intraoral photograph of a lower back quadrant with the cheek held aside; a mouth mirror at the lower right reflects the chewing surface of a molar whose pits and fissures are filled with a pale opaque material, while the teeth seen directly look natural. — Image: Roquex · CC0 · source
• A typodont model of the upper and lower teeth on a bench, with home-care aids laid out in front of it: a boxed dispenser with a fine thread pulled out of it, a green rubber-tipped stick, a blue and white tongue cleaner, a yellow toothbrush with teal bristles, and four small color-coded brushes with fine tapered tips in graded sizes. — Image: Milenafoto · CC BY-SA 3.0 · source
• A dark blue triangular nasal hood lying on a white surface, a pale round disc set into its front and a green connector on each side joining a ribbed flexible hose. — Image: Sch1912 · CC BY-SA 4.0 · source
• Upper and lower gypsum dental casts held with their teeth meeting, clamped between the two arms of a black bench-top articulator; a pale mounting band bonds the trimmed flat base of each cast to the arm beyond it, and adjusting screws stand at the rear. — Image: Lee Haywood · CC BY-SA 2.0 · source
• Colour-coded drawing of a skull cut down the midline and seen from inside. Towards the middle of the cranial floor a saddle-shaped hollow is labelled sella turcica, with its hypophyseal fossa, and it is sunk into the upper surface of the sphenoid bone, which is named just beside it. The frontal and sphenoid sinuses, the crista galli, the cribriform and perpendicular plates, the vomer, palatine bone, maxilla, inferior nasal concha, the pterygoid plates and the mandible with its foramen and lingula are labelled as well. — Image: OpenStax College, Anatomy & Physiology (Connexions), 2013 · CC BY 3.0 · source
• Colour-coded drawing of the skull from the right side, each bone in its own tint. A bracket labelled zygomatic arch spans the bar of bone running forward from in front of the ear to the cheek. Its back half is labelled as the zygomatic process of the temporal bone and its front half as the temporal process of the zygomatic bone, and the zygomatic bone itself is named beside it. The frontal, parietal, temporal, occipital and sphenoid bones, the maxilla and the mandible, the mastoid and styloid processes and the external acoustic meatus are labelled around them. — Image: OpenStax College, Anatomy & Physiology (Connexions), 2013 · CC BY 3.0 · source
• Line drawing of a lower jaw on its own seen from the right, the teeth towards the right of the frame, with a small skull inset showing where it sits. The upright ramus ends above in two projections separated by the mandibular notch: the coronoid process at the front, nearer the teeth, and the condylar process carrying the mandibular condyle behind it. The ramus, the body and the angle, the alveolar process, the mylohyoid line, the mandibular foramen and lingula, the mental protuberance and the mental foramen are labelled too. — Image: OpenStax College, Anatomy & Physiology (Connexions), 2013 · CC BY 3.0 · source
• Schematic of a head in profile on a black ground with the trigeminal nerve drawn in yellow. Three divisions are named where the nerve leaves the brainstem: the ophthalmic division V1, running forward to the forehead and the eye; the maxillary division V2, which fans out over the upper jaw and sends fine twigs down to the upper teeth; and the mandibular division V3 below them. The lingual and inferior alveolar nerves are labelled lower down. — Image: Romano N, Federici M, Castaldi A — Insights into Imaging 10:33 (2019) · CC BY 4.0 · source
• Line drawing of an open mouth seen from the front, twenty primary teeth drawn in the two arches with wide spaces between them. Leader lines carry the full name of every tooth to the margins. Each quadrant lists five names and five only, in this order outward from the middle: central incisor, lateral incisor, canine, first molar, second molar. No premolar appears in any quadrant. — Image: Gregory david baker, Vectorization: Mrmw · CC BY-SA 4.0 · source
• Line drawing of an open mouth seen from the front, all thirty-two permanent teeth drawn in the two arches. Leader lines run out to both margins and every tooth carries its full name in three parts: the arch, the side, and the tooth. Eight names run down each margin for the upper arch and eight for the lower. The names use the words canine and premolar rather than cuspid and bicuspid. The tongue and palate are drawn but not labelled. — Image: Gregory david baker, Vectorization: Mrmw · CC BY-SA 4.0 · source
• Hand-drawn outline of a lower first molar seen from its biting surface, Buccal printed at the top and Lingual at the bottom. Five cusps are labelled around the rim: Mesiobuccal, Distobuccal and Distal along the top and right, Mesiolingual and Distolingual along the bottom. Three grooves are labelled between them, Buccal Groove, Distobuccal Groove and Lingual groove, together with a Mesial Pit, a Distal Pit and one further label reading Lewis Offset. — Image: Acuteadvise · CC BY-SA 3.0 · source
• Macro photograph of a dry upper jaw specimen against a black ground, the front teeth still standing in their bone. Across the outer surface of each front tooth run several narrow horizontal bands, parallel to one another and to the gum margin, stained a little browner than the enamel between them and set in rows down the crown. The biting edges are smooth and glossy and the bands do not reach them. — Image: Otis Historical Archives Nat'l Museum of Health & Medicine · CC BY 2.0 · source
• A gloved finger holds back the upper lip. A mint-green prophy angle enters from the right and its small blue rubber cup is pressed against the outer surface of an upper back tooth; the neighbouring upper teeth meet one another at closed contacts alongside the cup. — Image: Walter Siegmund (image cropped) · CC BY 2.5 · source
• Wall-mounted intraoral x-ray unit seen across a clinic wall. A folded scissor extension arm rises up the left of the frame to a horizontal support arm, and the tubehead hangs from its far end, rotated so its branding reads upside down. A short open-ended cylinder is fixed beneath the tubehead, pointing at the floor. On the right, a separate wall-mounted control panel with a numeric display reading 0.160 and a keypad of tooth-region icons is screwed to a backing board; above it hang a 'Pregnant or think you might be' patient poster and a yellow 'Caution Radiation - Warning' placard. Nothing in the photograph is arrowed or labelled. — Image: Kiran891 · CC BY-SA 4.0 · source
• Digital periapical radiograph of an impacted lower third molar — Image: Nizil Shah · CC BY-SA 4.0 · source
• Panoramic radiograph of an adult with both arches in view. On the patient's right an upper canine has not erupted: it lies in the bone with its crown pointing down and forward, overlapping the roots of the upper teeth beside it. Both lower third molars are unerupted and tilted forward. A dense bright line follows the bottom outline of the lower jaw from one side to the other. A small dense metallic object records on each side beyond the jaws at ear level, and orientation letters R and L sit in the lower corners. — Image: Challiyan · CC BY-SA 4.0 · source
• A flat personnel dosimetry badge in a clear plastic holder beside a red ring dosimeter, both labelled CONTROL, lying on a pale bench — Image: Reconrabbit · CC0 · source
• WARNING X-RAY RADIATION sign with the black radiation trefoil symbol mounted on the blue door of a radiography room — Image: أمين · CC BY-SA 4.0 · source
• Wall-mounted intraoral dental x-ray unit with extension arm and round position indicating device — Image: Ptrump16 · CC BY-SA 4.0 · source
• Assortment of heavy chemical-resistant utility gloves in latex, nitrile, neoprene and butyl, all with long cuffs that extend over the wrist — Image: Work-psa · CC BY-SA 3.0 · source
• Two set dark-purple dental impressions in metal perforated stock trays lying in a perforated plastic strainer basket inside a clear-lidded plastic immersion container on a bench — Image: Politikaner · CC BY-SA 3.0 · source
• Two gloved hands wiping the blue upholstered headrest of a dental chair with a white disposable wipe, an operatory counter blurred behind — Image: U.S. Air Force photo by Senior Airman Jessica Blair · Public domain · source
• A dental assistant in a disposable gown, surgical mask, wraparound safety glasses, bouffant cap and gloves stands at the raised back of an empty dental chair in an operatory while a second person in scrubs watches holding a checklist; unsheathed handpiece tubing hangs from the delivery arm — Image: U.S. Air Force photo by Airman 1st Class Jessel Fabara · Public domain · source
• Dental technician wearing a hair cover wrapping an instrument set in blue sterilization wrap at a sterile processing bench, with a roll of indicator tape at hand — Image: U.S. Air Force photo by Senior Airman Dieondiere Jefferies · Public domain (US Air Force) · source
• Hands in heavy green utility gloves and a blue gown seating two metal dental handpieces onto the coupling spigots of a benchtop automated handpiece cleaning and lubrication unit with a numbered control panel — Image: U.S. Air Force photo by Senior Airman Tallon Bratton · Public domain · source
• Yellow puncture-resistant sharps container with red lid open and a marked fill line labeled DANGER — Image: Stefan Bellini · CC0 · source
• Two translucent plastic dispensing bottles on a bench, one labelled Ethyl Alcohol CH3CH2OH with a white cap and side spout and one labelled Acetone CH3COCH3 with a red cap, each label carrying a four-colour NFPA 704 hazard diamond, a Flammable flame symbol, target organs and effects, route of entry and a CAS number — Image: Nuno Nogueira (Nmnogueira) · CC BY-SA 2.5 · source
• Printed safety data sheet showing numbered sections including Section 4 First Aid, Section 5 Fire Fighting Measures, Section 6 Accidental Release and Section 7 Handling and Storage — Image: Jeffrey M. Vinocur · CC BY 2.5 · source
• Two prefilled syringes side by side on a grey background: the upper one before use with its needle hidden under a rigid tip cap, the lower one after use with the plunger fully depressed and a transparent slotted safety sleeve slid forward so the needle is enclosed inside it — Image: Frank C. Müller · CC BY-SA 4.0 · source
• Close intraoral photograph with the lower lip retracted by a finger, both front arches in frame. The upper incisors are pale and clean. Across the necks of the lower front teeth lies a thick yellow-brown build-up that follows the gumline, heaviest on the left of the frame. The gum is pale pink along most of its margin, with one small reddened area low on the left. No arrows, letters or measuring markers appear. — Image: Roquex · CC0 1.0 · source
• Three shiny stainless-steel appliances lying on a pale surface: one with a plain round bow and two small pointed jaws, one seen from above with a flat winged projection on each side and two small holes, and one seen from the front with a broad marked bow and two curved jaws. — Image: Santhyego · CC BY-SA 3.0 · source
• Five hinged extraction forceps laid out in a row on a white surface, each with a gold-colored knurled handle and a polished steel jaw, the jaws curving and angling differently from one instrument to the next. — Image: Hillcrestpvtltd · CC BY-SA 3.0 · source
• Close-up in a darkened operatory: a gloved hand holds a cordless wand with a lit display panel and angles its slim black tip into the slightly open mouth of a reclined patient, throwing intense blue light onto one upper tooth; the patient's eyes are covered by dark wraparound glasses. — Image: U.S. Air Force photo by Airman 1st Class Clayton Cupit · Public domain · source
• Close-up of a patient's mouth with the upper lip held back by a gloved finger; a mint-green prophy angle enters from the right and its small blue rubber cup is pressed against the outer surface of an upper back tooth. — Image: Walter Siegmund (image cropped) · CC BY 2.5 · source
• A blue-gloved hand holds an upper-arch impression by the handle of its stock tray. The white material has taken up the whole arch of tooth indentations and the palate, and its surface is still wet and glistening. — Image: Teemeah · CC BY-SA 3.0 · source
• Colour illustration of a molar cut lengthways in the jaw. Enamel, dentin, pulp, the root canal and the nerves and blood vessels running in it are labelled on the tooth, with the gums and the surrounding bone named around it. The gum is drawn lapping over the lowest part of the enamel cap, so that part of the enamelled surface lies hidden beneath it, and the bracket marked crown reaches down behind the gum to the level where the enamel ends. — Image: BruceBlaus (Blausen Medical) · CC BY 3.0 · source
• Drawing of the underside of the brain with the cranial nerves picked out in yellow. All twelve pairs are named with their Roman numerals, from the olfactory nerve I at the front to the hypoglossal nerve XII at the back. The trigeminal nerve V is drawn thicker than any of the others and leaves the side of the brainstem. — Image: OpenStax, Anatomy & Physiology (OpenStax CNX) · CC BY 4.0 · source

Who makes this

Dentalingo and these pages are made by one person, under the name Laborsam, with a mechanical-engineering degree and an MEP/HVAC design background, who builds study and work apps. That person is not a dental professional, which is why every answer on these pages points to its source instead of asking you to take it on trust.

About Yusuf Can Samiloglu