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RDA (AMT) practice questions

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Question 1Clinical / Chairside Assisting Procedures

Which instrument is used to detect roughness and carious lesions on a tooth surface?

  1. A spoon excavator
  2. An amalgam burnisher
  3. A sharp explorer Correct answer.
  4. A periodontal probe

Explanation

The explorer has a fine, flexible point that is drawn across the surface so the clinician can feel roughness, ditches and softened enamel or dentin. This tactile feedback makes it the standard examination instrument for caries detection.

Question 2Clinical / Chairside Assisting Procedures

During a lengthy restorative appointment, which device should be used to remove large volumes of water and debris from the mouth?

  1. An air-water syringe
  2. A high-volume evacuator Correct answer.
  3. A surgical suction tip resting in the vestibule
  4. A saliva ejector

Explanation

The high-volume evacuator has a wide-bore tip and a much higher vacuum than a saliva ejector, so it clears pooled water, blood and debris generated by high-speed instrumentation. The saliva ejector moves only small volumes of fluid and is not adequate during restorative work.

Question 3Clinical / Chairside Assisting Procedures

Under standard precautions, when are treatment gloves donned?

  1. Before the mask and protective eyewear
  2. Before the gown is tied at the neck
  3. After the gown, mask and eyewear are in place Correct answer.
  4. Only if the patient has a known bloodborne infection

Explanation

PPE is applied in a sequence that leaves the gloves as the final barrier: hand hygiene first, then gown, mask and eye protection, then gloves. Gloves are also removed first when doffing.

Question 4Clinical / Chairside Assisting Procedures

Which item is used to create the holes for the teeth in a sheet of rubber dam?

  1. Rubber dam forceps
  2. Rubber dam clamp
  3. Rubber dam frame
  4. Rubber dam punch Correct answer.

Explanation

The rubber dam punch carries a rotating table of graduated holes and a sharp plunger that cuts a clean, correctly sized hole in the sheet. Forceps place the clamp, and the frame holds the sheet stretched.

Question 5Clinical / Chairside Assisting Procedures

A mouth mirror is most often used during cavity preparation to:

  1. Reflect light and provide indirect vision Correct answer.
  2. Condense amalgam into the preparation
  3. Retract the tongue and cheek throughout the procedure
  4. Cut and shape enamel margins

Explanation

The mirror reflects light onto the field and allows the clinician to view surfaces that cannot be seen directly, such as the lingual of anterior teeth or the distal of posterior teeth. It is a viewing instrument, not a cutting or condensing instrument.

Question 6Clinical / Chairside Assisting Procedures

Why is aspiration performed before injecting local anesthetic?

  1. To warm the anesthetic solution
  2. To confirm the cartridge has not leaked
  3. To check the needle is not in a blood vessel Correct answer.
  4. To shorten the onset of anesthesia

Explanation

Drawing back on the plunger before depositing solution reveals whether the needle bevel has entered a vessel. A positive aspiration means the needle must be repositioned before any solution is deposited.

Question 7Clinical / Chairside Assisting Procedures

Which handpiece accepts a latch-type bur and is used for finishing and polishing?

  1. A high-speed air turbine handpiece
  2. An ultrasonic scaler insert
  3. A surgical straight handpiece
  4. A low-speed contra-angle handpiece Correct answer.

Explanation

Latch-type burs have a grooved base that locks into the spring chuck of a low-speed contra-angle, which turns slowly for finishing, polishing and caries removal. High-speed handpieces accept friction-grip shanks instead.

Question 8Clinical / Chairside Assisting Procedures

How should an instrument be transferred to the dentist in four-handed dentistry?

  1. Placed in the dentist's palm while the dentist watches the field
  2. Placed on the bracket table for the dentist to pick up
  3. Held at the handle end in the transfer zone Correct answer.
  4. Handed over with the working end aimed at the dentist's fingers

Explanation

Instruments are passed at a transfer zone near the patient's chin, gripped by the handle end so the dentist can take them without looking away from the operating field. The working end stays oriented toward the patient.

Question 9Clinical / Chairside Assisting Procedures

A Tofflemire retainer and matrix band are placed to:

  1. Measure the width of the gingival seat
  2. Isolate the tooth from saliva and blood
  3. Protect the tongue and cheek throughout the preparation
  4. Confine material and restore proximal contour Correct answer.

Explanation

The band replaces the missing proximal wall so restorative material can be condensed under pressure, and it re-establishes contact and contour. It is a shaping and containment device, not an isolation device.

Question 10Clinical / Chairside Assisting Procedures

Which finding indicates that an amalgam mix has been over-triturated?

  1. The mix is shiny, soupy and clings to the capsule Correct answer.
  2. The mix hardens before it can be placed in the tooth
  3. The mix is dry and crumbly in the capsule
  4. The mix forms a firm ball that does not adapt well

Explanation

Over-triturated amalgam releases excess mercury, so the mix becomes wet, shiny and sticky and loses its coherent plastic consistency. An under-triturated mix is dry, crumbly and weak.

Question 11Clinical / Chairside Assisting Procedures

Sutures placed after a routine extraction are usually removed after how many days?

  1. 3 to 4 days
  2. 1 to 2 days
  3. 5 to 7 days Correct answer.
  4. 14 to 21 days

Explanation

Intraoral sutures are generally removed at 5 to 7 days, when initial epithelial healing has occurred but before the suture tract becomes heavily epithelialized. Removing them too early risks wound dehiscence and too late leaves a tract that is harder to close.

Question 12Clinical / Chairside Assisting Procedures

Which change will make an alginate impression set faster?

  1. Spatulating with a stiff spatula
  2. Using warmer water Correct answer.
  3. Mixing in a flexible plastic bowl
  4. Using cooler water

Explanation

Alginate gelation is temperature dependent, so warmer water shortens the setting time and cooler water lengthens it. The water-to-powder ratio affects strength and consistency more than speed.

Question 13Clinical / Chairside Assisting Procedures

Where should the assistant position the high-volume evacuator tip during a restorative procedure?

  1. In the buccal vestibule of the opposite side
  2. Near the operating site, clear of the dentist's view Correct answer.
  3. Immediately behind the last molar
  4. Resting lightly against the soft palate at the back of the mouth

Explanation

The tip is kept at the margin of the operating field, close enough to catch the spray and debris from the handpiece without obscuring the dentist's line of sight. It is repositioned as the dentist moves around the arch.

Question 14Clinical / Chairside Assisting Procedures

A rubber dam clamp is placed on an anchor tooth to:

  1. Record the mesiodistal width of the tooth
  2. Lift the sheet away from the teeth
  3. Punch holes at the correct spacing
  4. Retain the dam and retract the gingival tissue Correct answer.

Explanation

The clamp grips the cervical neck of the anchor tooth, holding the sheet under tension and displacing the gingiva slightly away from the margin. This gives both retention and a clean field.

Question 15Clinical / Chairside Assisting Procedures

Gingival retraction cord is placed before which procedure?

  1. Sealant application
  2. Topical fluoride varnish
  3. Simple extraction
  4. Impression for a crown Correct answer.

Explanation

Cord is packed into the sulcus to push the gingiva laterally so impression material can flow past the margin and record the finish line. It is removed just before the impression is taken.

Question 16Clinical / Chairside Assisting Procedures

Which instruction should be given to a patient after a tooth extraction?

  1. Rinse vigorously with warm saline every hour today
  2. Apply a warm compress to the cheek for 20 minutes
  3. Drink through a straw to protect the clot
  4. Avoid rinsing, straws and smoking for the first 24 hours Correct answer.

Explanation

Rinsing, suction and heat disturb the forming clot and can lead to dry socket or renewed bleeding. The patient should keep the gauze in place as directed and avoid these activities for the first day.

Question 17Clinical / Chairside Assisting Procedures

When should tooth shade be selected for a crown?

  1. After the rubber dam has been placed
  2. Under the operatory overhead light
  3. At the start of the visit, before dehydration Correct answer.
  4. After the preparation, with the tooth dried

Explanation

Shade is matched before the tooth dries, because dehydration lightens enamel and gives a false reading. Daylight or a color-corrected light is preferred because operatory lighting shifts hue.

Question 18Clinical / Chairside Assisting Procedures

A bur with a friction-grip shank is designed for use in which handpiece?

  1. A laboratory lathe
  2. A high-speed air turbine Correct answer.
  3. A low-speed latch contra-angle
  4. A surgical straight handpiece

Explanation

Friction-grip shanks are smooth and are held by friction in the chuck of an air-turbine handpiece, which is why they must be seated fully before use. Latch shanks are used in low-speed handpieces.

Question 19Clinical / Chairside Assisting Procedures

Which step directly precedes acid etching of a pit and fissure sealant site?

  1. Curing with the light for 20 seconds
  2. Cleaning the surface with pumice and rinsing well Correct answer.
  3. Drying the tooth with the air syringe
  4. Applying the sealant with a brush

Explanation

The occlusal surface is first cleaned with pumice or a bristle brush and rinsed to remove pellicle and debris, so the acid can reach the enamel. Etching, drying, sealing and curing follow in that order.

Question 20Clinical / Chairside Assisting Procedures

Where should the saliva ejector be placed?

  1. Against the retromolar pad
  2. Hanging over the lower incisors
  3. In the floor of the mouth without pressing tissue Correct answer.
  4. In the buccal vestibule of the quadrant being treated

Explanation

The saliva ejector works by low vacuum, so it is placed in the most dependent part of the mouth where saliva pools, with the tip resting lightly so it does not draw soft tissue into the openings.

Question 21Clinical / Chairside Assisting Procedures

How many milligrams of lidocaine are contained in one 1.8 mL cartridge of 2% lidocaine?

  1. 54 mg
  2. 36 mg Correct answer.
  3. 18 mg
  4. 72 mg

Explanation

A 2% solution contains 2 g per 100 mL, which is 20 mg per mL. Multiplying 1.8 mL by 20 mg/mL gives 36 mg of lidocaine per cartridge.

Question 22Clinical / Chairside Assisting Procedures

For a healthy 70 kg adult, the maximum recommended dose of 2% lidocaine with 1:100,000 epinephrine is approximately:

  1. 300 mg Correct answer.
  2. 150 mg
  3. 700 mg
  4. 500 mg

Explanation

The maximum recommended dose of lidocaine with epinephrine is about 4.4 mg/kg, and 4.4 mg/kg multiplied by 70 kg is roughly 300 mg, or about eight 1.8 mL cartridges. The absolute cap for a healthy adult is 300 mg.

Question 23Clinical / Chairside Assisting Procedures

A patient becomes pale and diaphoretic with a slow pulse during an injection. What is the initial management?

  1. Lay the patient supine, elevate the legs, give oxygen Correct answer.
  2. Sit the patient upright and provide a respiratory stimulant
  3. Give oral glucose and reassess in 10 minutes
  4. Begin chest compressions immediately

Explanation

This presentation is consistent with vasovagal syncope. Supine positioning with the legs elevated restores cerebral perfusion, oxygen is administered, and vital signs are monitored until the patient recovers.

Question 24Clinical / Chairside Assisting Procedures

Nitrous oxide/oxygen sedation is contraindicated for a patient with which condition?

  1. A myocardial infarction two years ago
  2. A current pneumothorax Correct answer.
  3. Mild essential hypertension
  4. Well-controlled asthma

Explanation

Nitrous oxide diffuses into closed, gas-filled spaces faster than nitrogen leaves them, so it can expand a pneumothorax, a bowel obstruction or an intraocular gas bubble. Stable asthma and old, stable cardiac disease are not contraindications.

Question 25Clinical / Chairside Assisting Procedures

Which matrix is most appropriate for restoring a Class IV composite on a maxillary central incisor?

  1. An ivory matrix holder with a metal band
  2. A copper band with compound
  3. A metal Tofflemire band
  4. A clear plastic matrix strip and wedge Correct answer.

Explanation

A clear matrix allows the curing light to pass into the material and can be adapted to rebuild the incisal and proximal anatomy. Metal devices block light and cannot be used for light-cured anterior restorations.

Question 26Clinical / Chairside Assisting Procedures

During a procedure on the maxillary left quadrant, the dentist asks the assistant to position the mouth mirror. What is the primary purpose of the mirror in this situation?

  1. To condense restorative material into the preparation
  2. To retract tissue and provide indirect vision Correct answer.
  3. To measure the depth of periodontal pockets
  4. To remove soft carious dentin from the cavity

Explanation

The mouth mirror serves three main functions: indirect vision, retraction of soft tissue, and reflection of light onto the operating field. It is not designed for cutting, measuring, or packing material.

Question 27Clinical / Chairside Assisting Procedures

Which instrument is used to measure the depth of the gingival sulcus around a tooth?

  1. Periodontal probe Correct answer.
  2. Sickle scaler
  3. Universal curette
  4. Explorer

Explanation

A periodontal probe has calibrated markings in millimeters that allow measurement of sulcus and pocket depth. Explorers and scalers have sharp tips designed for detection or removal of deposits, not measurement.

Question 28Clinical / Chairside Assisting Procedures

Which instrument is used to grasp and guide the suture needle during suturing?

  1. Needle holder Correct answer.
  2. Tissue forceps
  3. Hemostat
  4. Suture scissors

Explanation

A needle holder has a short, stout beveled beak and a ratchet that grips the curved needle securely during passage through tissue. Hemostats and forceps are not designed to resist the torque placed on a needle.

Question 29Clinical / Chairside Assisting Procedures

Articulating paper is used during a restorative appointment to:

  1. Measure the patient's pulpal response
  2. Polish the restoration to a smooth finish
  3. Isolate the tooth being restored
  4. Mark the points of occlusal contact Correct answer.

Explanation

Articulating paper is placed between the teeth while the patient taps and slides, leaving colored marks that show where occlusal contacts occur. This guides adjustment of the restoration so contacts are even in centric occlusion and excursive movements.

Question 30Clinical / Chairside Assisting Procedures

Where is a cotton roll placed to control moisture for a mandibular posterior restoration?

  1. In the buccal vestibule next to the tooth Correct answer.
  2. Beneath the tongue on the opposite side
  3. Over the buccal vestibule on the opposite side
  4. On the occlusal surface of the tooth

Explanation

For mandibular posterior work, cotton rolls are placed in the buccal vestibule on the working side and often lingually to absorb saliva and retract the cheek or tongue. Rolls placed on the opposite side or over the operative site do not protect the field.

Question 31Clinical / Chairside Assisting Procedures

A rubber cup mounted on a prophylaxis angle is used to:

  1. Condense amalgam into a cavity
  2. Cut enamel to shape a preparation
  3. Retract gingival tissue for access
  4. Apply polishing paste to tooth surfaces Correct answer.

Explanation

The rubber cup is a soft, flexible polishing agent carrier used with prophylaxis paste on the prophylaxis angle. Because it is not abrasive to enamel, it cleans and polishes rather than cutting.

Question 32Clinical / Chairside Assisting Procedures

Which item of personal protective equipment is worn primarily to protect the assistant's eyes from splatter and debris?

  1. Utility gloves
  2. Disposable gown
  3. Protective eyewear with side shields Correct answer.
  4. Face mask

Explanation

Protective eyewear with side shields blocks splatter, aerosol, and debris from entering the eyes from the front and sides. Masks, gloves, and gowns protect other areas and do not shield the eyes.

Question 33Clinical / Chairside Assisting Procedures

How often should a biologic spore test be run on a steam autoclave used for instrument sterilization?

  1. After every load
  2. Weekly Correct answer.
  3. Daily
  4. Monthly

Explanation

Routine biologic monitoring with a spore test is recommended at least weekly for each sterilizer, with every load containing an implant also monitored. More frequent testing may be required by local regulation or after a failure.

Question 34Clinical / Chairside Assisting Procedures

What is the main function of a wedge placed with a Class II matrix band?

  1. To mark the proximal contact for later adjustment
  2. To hold the rubber dam frame in place
  3. To keep the band from touching the adjacent tooth
  4. To adapt the band to the gingival margin Correct answer.

Explanation

The wedge is inserted from the buccal or lingual embrasure to seat the matrix band tightly against the gingival margin and to protect the interproximal papilla. Seating the band prevents overhangs and helps recreate the proximal contour.

Question 35Clinical / Chairside Assisting Procedures

How should the curing light tip be positioned when photopolymerizing a composite restoration?

  1. Several centimeters away to cover a wider area
  2. At a 45-degree angle about 5 mm away
  3. Parallel to the long axis of the tooth
  4. Close to and perpendicular to the surface Correct answer.

Explanation

Curing effectiveness is greatest when the tip is held as close as possible to the restoration and perpendicular to its surface, so light intensity is delivered directly into the material. Angulation, distance, and thickness all reduce the energy reaching the composite.

Question 36Clinical / Chairside Assisting Procedures

Which instrument is used to remove soft, infected dentin from a cavity preparation?

  1. Chisel
  2. Spoon excavator Correct answer.
  3. Burnisher
  4. Periodontal curette

Explanation

The spoon excavator has a rounded, curved blade that scoops out softened, infected dentin while leaving firmer dentin intact. Its shape allows controlled removal without gouging the preparation walls.

Question 37Clinical / Chairside Assisting Procedures

If an alginate impression mix contains too much water, the resulting impression will be:

  1. Stronger and more accurate
  2. Weaker and less dimensionally stable Correct answer.
  3. Faster setting and more brittle
  4. Thicker and easier to control

Explanation

Excess water dilutes the alginate powder, producing a mix with reduced strength and greater shrinkage and distortion as it sets. The water-to-powder ratio must be measured according to the manufacturer's instructions for predictable results.

Question 38Clinical / Chairside Assisting Procedures

Which type of gypsum product is used primarily for fabricating dies for crown and bridge work?

  1. Type III dental stone
  2. Type IV high-strength stone Correct answer.
  3. Type I impression plaster
  4. Type II model plaster

Explanation

Type IV stone is a high-strength, low-expansion gypsum product that produces hard, accurate dies for indirect restorations. Its low setting expansion preserves the precision needed for crown and bridge fit.

Question 39Clinical / Chairside Assisting Procedures

Where is a maxillary infiltration injection typically administered?

  1. In the palatal tissue directly over the apex
  2. At the lingual gingival margin
  3. Into the retromolar pad
  4. In the mucobuccal fold above the tooth apex Correct answer.

Explanation

For maxillary infiltration, the needle is directed into the mucobuccal fold above the apex of the target tooth so solution diffuses through porous bone to the root apex. Palatal or lingual injections are used for different purposes and are more uncomfortable.

Question 40Clinical / Chairside Assisting Procedures

Which matrix system is preferred for a Class II composite restoration in a posterior tooth to achieve a tight proximal contact?

  1. A Tofflemire band placed without a wedge
  2. An acetate crown form
  3. A clear plastic strip matrix
  4. A sectional matrix with a separating ring Correct answer.

Explanation

A sectional matrix with a separating ring creates a tight proximal contact and appropriate contour for posterior composites. The ring separates the teeth slightly and holds the curved section firmly against the preparation.

Question 41Clinical / Chairside Assisting Procedures

After fluoride varnish is applied, the patient should be instructed to:

  1. Rinse thoroughly with water right away
  2. Drink citrus juice to activate the varnish
  3. Brush the varnish off after one hour
  4. Avoid brushing and hard foods for several hours Correct answer.

Explanation

Varnish is painted onto the teeth and left in place so the fluoride remains in contact with enamel; patients should avoid brushing and hard or hot foods for several hours. Rinsing or scrubbing removes the coating before it can be effective.

Question 42Clinical / Chairside Assisting Procedures

What is the correct chair position for a patient during most restorative treatment of the maxillary arch?

  1. Fully supine with the head lower than the feet
  2. Semi-supine with the head slightly higher than the feet Correct answer.
  3. Turned 45 degrees toward the operator
  4. Upright at 90 degrees

Explanation

For maxillary restorative work the patient reclines to a semi-supine position with the head slightly elevated, which gives the operator access and keeps the field comfortable for the patient. A head-down position is avoided because it increases pressure and patient discomfort.

Question 43Clinical / Chairside Assisting Procedures

What is the purpose of applying topical anesthetic before an injection?

  1. To reduce bleeding at the injection site
  2. To sterilize the injection site
  3. To prolong the effect of the injected anesthetic
  4. To numb the mucosa at the needle entry point Correct answer.

Explanation

Topical anesthetic is applied to the dried mucosa for about one to two minutes to reduce the pain of needle penetration. It acts only on the surface and does not affect bleeding or the duration of the injected solution.

Question 44Clinical / Chairside Assisting Procedures

Why are cleaned instruments packaged in self-sealing sterilization pouches before processing?

  1. It removes the need for biologic monitoring
  2. It maintains sterility after processing until the pouch is opened Correct answer.
  3. It keeps the instruments moist during the cycle
  4. It allows instruments to be stored without a date

Explanation

Pouches allow steam penetration during the cycle and then protect the contents from contamination after sterilization, preserving sterility until the package is opened. Each package must still be dated and monitored like any other load.

Question 45Clinical / Chairside Assisting Procedures

How should a high-speed handpiece be maintained between patients?

  1. Soak it in glutaraldehyde overnight
  2. Autoclave it without cleaning first
  3. Wipe it with alcohol and return it to the drawer
  4. Clean and lubricate it, then sterilize it by steam Correct answer.

Explanation

Handpieces must be cleaned and lubricated according to the manufacturer's instructions and then sterilized, usually by steam autoclave. Internal lubrication protects the turbine and bearings from damage during sterilization and use.

Question 46Clinical / Chairside Assisting Procedures

A patient reports a history of uncontrolled hyperthyroidism. Which component of a local anesthetic cartridge is of greatest concern?

  1. The lidocaine hydrochloride
  2. The distilled water
  3. The epinephrine vasoconstrictor Correct answer.
  4. The sodium chloride

Explanation

A patient with uncontrolled hyperthyroidism already has an elevated metabolic rate and is sensitive to catecholamines; exogenous epinephrine can precipitate tachycardia, palpitations, and arrhythmias. In such patients a plain anesthetic or careful dose reduction with medical consultation is considered.

Question 47Clinical / Chairside Assisting Procedures

Which amide local anesthetic has been associated with methemoglobinemia, particularly at higher doses?

  1. Mepivacaine
  2. Prilocaine Correct answer.
  3. Bupivacaine
  4. Articaine

Explanation

Prilocaine is metabolized to o-toluidine, which oxidizes hemoglobin to methemoglobin, so high doses can cause cyanosis unresponsive to oxygen. Benzocaine, an ester topical, shares this risk in susceptible patients.

Question 48Clinical / Chairside Assisting Procedures

Three days after a mandibular molar extraction, a patient reports severe throbbing pain and a foul taste. The socket is empty and bone is visible. This presentation is most consistent with:

  1. A retained root tip
  2. Osteomyelitis
  3. Alveolar osteitis Correct answer.
  4. Normal healing

Explanation

Loss of the blood clot, exposed bone, severe pain beginning two to four days after extraction, and a foul odor or taste are classic signs of alveolar osteitis, or dry socket. Treatment involves gentle irrigation and placement of a medicated dressing.

Question 49Clinical / Chairside Assisting Procedures

Which suture material is absorbable and commonly used for closing superficial oral mucosa?

  1. Polypropylene
  2. Nylon
  3. Silk
  4. Plain gut Correct answer.

Explanation

Plain gut is a monofilament absorbable suture derived from collagen that is broken down by enzymatic digestion over days to weeks, making it useful for superficial mucosal closure where removal would be difficult. Silk, nylon, and polypropylene are nonabsorbable and must be removed.

Question 50Clinical / Chairside Assisting Procedures

A steam autoclave's weekly biologic indicator shows growth. What is the correct immediate action?

  1. Stop using the unit and reprocess recent loads Correct answer.
  2. Increase the cycle temperature and continue using the unit
  3. Continue use and retest at the next scheduled interval
  4. Discard only the items in the pouch that was tested

Explanation

A positive biologic indicator means the cycle did not achieve sterilization, so the unit must be taken out of service until it is serviced and passes retesting. Instruments processed since the last negative test must be recalled, reprocessed, and the event documented.