22 Chairside Assisting Practice Questions & Answers

1. 1. A treatment room is arranged for a right-handed operator, with the working areas described as positions on a clock face centered over the patient's head. In which zone does the dental assistant work?

   • A.The operator zone, from 7 o'clock to 12 o'clock
   • B.The transfer zone, from 4 o'clock to 7 o'clock
   • C.The assistant zone, from 2 o'clock to 4 o'clock✓ Answer
   • D.The static zone, from 12 o'clock to 2 o'clock

   The zones are defined by the operator's dominant hand. With a right-handed operator seated on the patient's right, the assistant takes the opposite side at 2 to 4 o'clock, which places her hands at the evacuation and transfer positions without crossing the operator's working path. The static zone behind the head holds the mobile cart, and the transfer zone from 4 to 7 o'clock is kept clear because instruments pass through it below the chin.

   Source: Bird & Robinson, Modern Dental Assisting — four-handed dentistry operating zonesReport a problem with this question

2. 2. The dentist working in an operatory is left-handed. How are the four operating zones arranged for that team?

   • A.Moved to the head of the chair, with the assistant at 11 to 1 o'clock
   • B.Mirrored across the patient's midline, with the assistant at 8 to 10 o'clock✓ Answer
   • C.Rotated one hour clockwise, with the assistant at 3 to 5 o'clock
   • D.Unchanged from the right-handed layout, with the assistant at 2 to 4 o'clock

   Zone assignment follows the hand that holds the handpiece, so a left-handed operator simply reverses the whole arrangement across the midline. The operator moves to the patient's left at roughly 12 to 5 o'clock and the assistant moves to the patient's right at 8 to 10 o'clock, keeping the transfer zone directly in front of the operator's free hand.

   Source: Bird & Robinson, Modern Dental Assisting — operating zones for left-handed operatorsReport a problem with this question

3. 3. An assistant is adjusting her stool at the start of a procedure. How should her seated position compare with the operator's?

   • A.Level with the operator, with her thighs tipped toward the patient
   • B.Higher than the patient, with her thighs tipped back from the chair
   • C.Lower than the operator, with her thighs held parallel to the floor
   • D.Higher than the operator, with her thighs held parallel to the floor✓ Answer

   Seating the assistant above the operator's eye level lets her see over his hands into the oral cavity, which is what makes anticipation of the next step possible. Thighs held parallel to the floor with the feet supported keeps the pelvis neutral and the back supported through a long appointment.

   Source: Bird & Robinson, Modern Dental Assisting — operator and assistant seating in four-handed dentistryReport a problem with this question

4. 4. During a single-handed instrument transfer, where does the exchange itself take place?

   • A.Over the patient's chest, just below the chin✓ Answer
   • B.Over the patient's face, level with the eyes
   • C.Behind the patient's head, near the headrest
   • D.Beside the patient's shoulder, at chair-arm level

   The transfer zone sits over the chest and below the chin because anything dropped there lands on the patient's bib rather than in the eyes or airway. Passing above the face risks a sharp instrument falling onto the face, and passing behind the head or off to the side forces the operator to break the fulcrum and look away from the field.

   Source: Bird & Robinson, Modern Dental Assisting — instrument transfer and the transfer zoneReport a problem with this question

5. 5. The operator signals for the next instrument while keeping a finger rest on the tooth. What does the assistant do first in a single-handed transfer?

   • A.Place the new instrument across the operator's index finger
   • B.Release the new instrument into the operator's palm
   • C.Rotate the new instrument so the handle faces upward
   • D.Retrieve the used instrument with her little finger✓ Answer

   In a single-handed transfer one hand does both jobs in sequence: the free little finger hooks and lifts the used instrument out of the operator's grasp, which empties the hand so the new instrument can be delivered into the same position. Delivering before retrieving leaves the operator holding two instruments and forces him to break the finger rest.

   Source: Bird & Robinson, Modern Dental Assisting — single-handed instrument transfer techniqueReport a problem with this question

6. 6. How is a hinged instrument such as extraction forceps passed to the operator?

   • A.Held near the hinge, with the beaks rested on the operator's fingertips and closed
   • B.Held by one beak, with the handles passed over the patient's face and the beaks open
   • C.Held near the hinge, with the handles placed into the operator's palm and the beaks closed✓ Answer
   • D.Held by the handles, with the beaks placed into the operator's palm and the beaks open

   A hinged instrument is grasped at the hinge so the assistant's fingers stay clear of the working ends, and the handles are what the operator must close on, so the handles are what is delivered to the palm. The beaks are kept closed during the pass so the sharp or gripping ends cannot catch tissue, the dam or the assistant's glove in transit.

   Source: Bird & Robinson, Modern Dental Assisting — transfer of hinged instrumentsReport a problem with this question

7. 7. An assistant is handed an unfamiliar double-ended instrument whose working ends are small, sharpened, spoon-shaped blades. What is this instrument used for?

   • A.Condensing amalgam alloy into a preparation
   • B.Smoothing the enamel at a cavosurface margin
   • C.Removing soft carious dentin from a preparation✓ Answer
   • D.Detecting calculus deposits along a root surface

   An instrument can be identified from the geometry of its working end. A curved, sharpened spoon-shaped blade is a scooping edge, which is what is needed to lift out soft decayed dentin without cutting sound tooth structure. A condenser ends in a flat blunt nib, a margin trimmer has a straight bevelled cutting edge, and an explorer ends in a fine wire point.

   Source: Bird & Robinson, Modern Dental Assisting — hand instrument design and classificationReport a problem with this question

8. 8. Apart from indirect vision, what is a routine use of the mouth mirror during an examination?

   • A.Carrying cotton pellets and small items to the field
   • B.Scraping soft deposits from the tooth surface in the field
   • C.Measuring the depth of the gingival sulcus at the field
   • D.Retracting the cheek and reflecting light into the field✓ Answer

   The mirror is a reflective surface on a rigid handle, so it does two things at once: its back and rim push the cheek or tongue away from the teeth, and its face bounces operatory light into a shadowed area. Carrying small items is the job of cotton pliers, measuring sulcus depth is the probe's job, and removing deposits belongs to scalers and curettes.

   Source: Bird & Robinson, Modern Dental Assisting — the basic examination setup: mirror, explorer and cotton pliersReport a problem with this question

9. 9. The operator is about to begin cutting a preparation with the high-speed handpiece. How does the assistant position the high-volume evacuator tip?

   • A.Placed after the handpiece, on the same surface that is being prepared
   • B.Placed before the handpiece, on the surface opposite the one being prepared✓ Answer
   • C.Placed after the handpiece, angled across the midline toward the tongue
   • D.Placed before the handpiece, resting against the soft tissue of the floor

   The tip goes in first because once the handpiece is in place there is no room to position the evacuator without bumping the operator's hand. Putting it on the opposite surface, slightly distal to the tooth, keeps it out of the operator's line of sight while still catching the water spray and aerosol as they come off the bur.

   Source: Bird & Robinson, Modern Dental Assisting — oral evacuation and high-volume evacuator placementReport a problem with this question

10. 10. Why is the high-volume evacuator, rather than the saliva ejector, used while the high-speed handpiece is cutting?

    • A.It applies a gentler suction that is more comfortable for the patient
    • B.It removes the large volume of water and aerosol the handpiece produces✓ Answer
    • C.It cools the rotating bur and replaces the spray from the handpiece
    • D.The patient can hold it in place while the assistant charts the visit

    A high-speed handpiece sprays coolant water continuously and throws a contaminated aerosol into the air. Only the wide-bore evacuator moves enough air per minute to clear that volume, keeping the field visible and reducing the spatter the team breathes; the narrow saliva ejector is built for low-volume pooled saliva between steps.

    Source: Bird & Robinson, Modern Dental Assisting — moisture control: high-volume evacuation versus the saliva ejectorReport a problem with this question

11. 11. What instruction to the patient prevents backflow of fluid from the saliva ejector into the mouth?

    • A.Do not raise the chair while the ejector runs
    • B.Do not swallow while the ejector tip is in the mouth
    • C.Do not rest the tongue against the ejector tip
    • D.Do not close the lips around the ejector tip✓ Answer

    Sealing the lips around the tip creates a partial vacuum in the mouth; when the pressure in the suction line momentarily drops below that, fluid already in the tubing can flow backward into the patient. Leaving the lips open keeps the mouth at atmospheric pressure so the gradient that drives backflow never forms.

    Source: CDC dental infection prevention guidance — saliva ejector backflowReport a problem with this question

12. 12. Before a dental dam clamp is placed, a length of floss is tied to its bow. What does this accomplish?

    • A.It allows retrieval if the clamp breaks or is swallowed✓ Answer
    • B.It keeps the clamp from rocking on the anchor tooth
    • C.It holds the clamp jaws open while the dam is stretched over it
    • D.It marks the clamp so it is returned to the right kit

    A clamp is a small metal object held under spring tension next to an open airway, and clamps do fracture at the bow. The floss stays outside the mouth so that a dislodged clamp or fragment can be pulled straight back out before it is swallowed or aspirated, which is the whole point of ligating it.

    Source: Bird & Robinson, Modern Dental Assisting — dental dam clamp selection and ligationReport a problem with this question

13. 13. After the dental dam is in place, the assistant helps invert the dam material into the gingival sulcus. What does inverting achieve?

    • A.A greater frame tension that keeps the dam from tearing
    • B.A looser dam that lets the operator reach farther back
    • C.A wider window of gingiva for seeing the margin clearly
    • D.A seal at the tooth neck that keeps saliva off the preparation✓ Answer

    A punched hole lies flat against the tooth and leaves a capillary gap at the neck through which crevicular fluid and saliva seep onto the field. Tucking the edge of the dam into the sulcus turns that flat contact into a cuff that grips the tooth, which is what makes the isolation actually dry.

    Source: Bird & Robinson, Modern Dental Assisting — dental dam placement and inversionReport a problem with this question

14. 14. A sealant is being placed on a maxillary first molar using cotton-roll isolation. Where does the cotton roll go?

    • A.Under the tongue in the floor of the mouth, over the sublingual ducts
    • B.In the mucobuccal fold beside the tooth, over the parotid duct✓ Answer
    • C.Between the tongue and the lingual surface of that same molar
    • D.Against the palate behind the incisors, over the incisive papilla

    Isolation works by blocking saliva at its source. The parotid gland empties through Stensen's duct, which opens in the cheek opposite the maxillary second molar, so a roll in the mucobuccal fold soaks up that flow before it reaches the occlusal surface being etched. The sublingual and submandibular ducts drain the lower arch, not the upper.

    Source: Bird & Robinson, Modern Dental Assisting — cotton-roll isolation and salivary duct openingsReport a problem with this question

15. 15. The dentist is about to restore a mandibular molar. How is the patient positioned?

    • A.Head below the feet, with the legs raised above the level of the heart
    • B.Sitting upright, with the chin raised and the head extended backward
    • C.Semi-supine, with the mandibular occlusal plane parallel to the floor✓ Answer
    • D.Fully supine, with the maxillary occlusal plane perpendicular to the floor

    Positioning is chosen so the operator can look directly at the surface being cut without bending over. Raising the patient slightly and having him open wide tips the lower occlusal plane flat, giving a straight line of sight down onto the mandibular teeth; the fully supine, perpendicular position is what the maxillary arch requires.

    Source: Bird & Robinson, Modern Dental Assisting — patient positioning for maxillary and mandibular treatmentReport a problem with this question

16. 16. Etched enamel is contaminated by saliva before the sealant material is applied. What should the team do?

    • A.Rinse, then dry and etch the enamel again before sealing✓ Answer
    • B.Wipe it with a cotton roll and extend the curing time
    • C.Apply fluoride varnish and place the sealant over it
    • D.Dry the surface with air and seal without re-etching

    Etching works by opening microscopic porosities in enamel that the resin flows into and locks onto. Saliva deposits a glycoprotein film that plugs those porosities within seconds, so no amount of drying or extra curing restores the bond; the surface has to be rinsed and etched again to reopen it.

    Source: Bird & Robinson, Modern Dental Assisting — pit and fissure sealant technique and moisture controlReport a problem with this question

17. 17. An assistant is removing a non-absorbable suture at a post-operative visit. How is each stitch cut and withdrawn?

    • A.Cut the loop at the tissue and draw the knot through it
    • B.Cut below the knot and pull toward the incision line✓ Answer
    • C.Cut above the knot and pull away from the incision line
    • D.Cut on both sides of the knot and lift the knot upward

    The knot sits on the surface and has been exposed to plaque and debris, while the strand under it has been inside the tissue. Cutting below the knot and drawing the suture toward the incision means only clean submerged thread travels through the tissue and the wound edges are pushed together rather than pulled apart.

    Source: Bird & Robinson, Modern Dental Assisting — suture removal technique in oral surgeryReport a problem with this question

18. 18. Three days after an extraction a patient returns with severe throbbing pain, a foul odor and a socket that looks empty. What treatment should the assistant prepare for?

    • A.Incision and drainage of the swelling over the socket
    • B.Re-suturing of the socket margins under local anesthesia
    • C.Irrigation of the socket and placement of a medicated dressing✓ Answer
    • D.Antibiotics alone, with no local treatment of the socket

    This picture is alveolar osteitis: the blood clot has broken down and left bare bone exposed to oral fluids and air, which is what produces the intense pain and the odor. Treatment is mechanical and palliative — flush the debris out and cover the exposed bone with a medicated dressing. It is not a pus-forming infection, so drainage or antibiotics alone do not address it.

    Source: Bird & Robinson, Modern Dental Assisting — postoperative complications: alveolar osteitis (dry socket)Report a problem with this question

19. 19. During an injection a patient turns pale, becomes sweaty and loses consciousness. What is the assistant's immediate action?

    • A.Lower the chair to supine and raise the patient's legs✓ Answer
    • B.Raise the chair fully upright and loosen the collar
    • C.Have the patient rebreathe into cupped hands while seated
    • D.Turn the patient onto one side and give sips of juice

    Syncope is a transient drop in blood flow to the brain. Laying the patient flat removes the height the heart has to pump against and elevating the legs returns pooled venous blood to the central circulation, so perfusion is restored by gravity alone. Sitting the patient up does the opposite and deepens the faint.

    Source: Little et al., Dental Management of the Medically Compromised Patient — syncope in the dental officeReport a problem with this question

20. 20. An anxious patient begins breathing rapidly and reports tingling fingers and lightheadedness. How should the team respond?

    • A.Sit the patient up and coach rebreathing into cupped hands✓ Answer
    • B.Sit the patient up and give the rescue bronchodilator inhaler
    • C.Lay the patient flat and start high-flow oxygen by face mask
    • D.Lay the patient flat and elevate the legs above the heart

    Hyperventilation blows off carbon dioxide, and it is the resulting low blood carbon dioxide that causes the tingling and dizziness. Rebreathing exhaled air raises carbon dioxide back toward normal, which is why supplemental oxygen is exactly the wrong treatment here even though the patient looks short of breath.

    Source: Little et al., Dental Management of the Medically Compromised Patient — hyperventilation syndromeReport a problem with this question

21. 21. A patient with known angina develops crushing chest pain that two doses of sublingual nitroglycerin do not relieve. What does the team do next?

    • A.Activate EMS, give oxygen and offer chewable aspirin✓ Answer
    • B.Give a third nitroglycerin dose and finish the restoration
    • C.Have the patient rebreathe into a bag until the pain eases
    • D.Lay the patient flat, raise the legs and offer orange juice

    Angina is relieved by nitroglycerin because the vessel spasm or narrowing is reversible; pain that persists after repeated doses signals that a vessel is occluded and heart muscle is dying. That makes it a time-dependent emergency, so the team calls for transport, supports oxygenation and gives aspirin to limit clot growth if the patient is not allergic.

    Source: Little et al., Dental Management of the Medically Compromised Patient — angina and acute myocardial infarctionReport a problem with this question

22. 22. Midway through an appointment a patient with diabetes becomes shaky, confused and sweaty, but is awake and able to swallow. What should be given?

    • A.An injection of insulin drawn from the emergency kit
    • B.An oral carbohydrate such as juice or glucose gel✓ Answer
    • C.An ammonia inhalant held under the patient's nose
    • D.Nothing by mouth, with the chair placed fully supine

    These signs come from a falling blood glucose, and the brain has no stored fuel of its own, so the deficit has to be corrected within minutes. A conscious patient who can protect the airway is given sugar by mouth; insulin would drive the glucose lower still, and withholding treatment wastes the window in which swallowing is safe.

    Source: Little et al., Dental Management of the Medically Compromised Patient — hypoglycemia in the dental patientReport a problem with this question

Practice questions based on the DANB Radiation Health and Safety (RHS), Infection Control (ICE), and General Chairside Assisting (GC) content outlines, CDC dental infection-prevention guidance, the OSHA Bloodborne Pathogens Standard, and ADA/FDA radiographic selection criteria. DANB, CDA, RHS, ICE, and GC are marks of the Dental Assisting National Board; this site is not affiliated with or endorsed by DANB. The duties a dental assistant may legally perform — and any radiography permit or certification required — are set by your own state dental board. Confirm current requirements with that board and with DANB before testing. About the DANB exams →