RDA Exam Prep Free practice test →

Free RDA Practice Questions

10 free, exam-style Registered Dental Assistant (RDA) (RDA) practice questions with answers and explanations. No signup required. Work through them below, then take the full free RDA practice test to study every exam domain.

The RDA exam has 210 questions and runs 2 hours 30 minutes.

These 10 free RDA questions are organized by exam domain, so you can see how each part of the Registered Dental Assistant (RDA) blueprint is tested. Reveal the answer and explanation under each question.

Domain 2: Dental Sciences 33.3% of exam

Question 1

Using the Universal Numbering System, a dental assistant charts an existing restoration on the permanent maxillary right first molar. Which tooth number should be recorded?

  1. #3
  2. #14
  3. #19
  4. #30
Show answer & explanation

Correct answer: A - #3

Question 2

A mouth mirror contacts mucous membranes during an examination but does not penetrate soft tissue or bone. Under the Spaulding classification applied to dental instruments, the mirror is correctly categorized as:

  1. A critical item requiring heat sterilization between patients
  2. A noncritical item needing only low-level surface disinfection
  3. A semicritical item that contacts mucosa but does not penetrate
  4. An environmental surface that is managed with a protective barrier
Show answer & explanation

Correct answer: C - A semicritical item that contacts mucosa but does not penetrate

Question 3

During a restorative procedure, a healthy adult patient becomes pale and lightheaded and then briefly loses consciousness. After activating help, the assistant's MOST appropriate immediate action is to:

  1. Raise the patient upright and offer a cup of cold water
  2. Start chest compressions and prepare to use the AED
  3. Place a nitroglycerin tablet under the patient's tongue
  4. Position the patient supine and slightly elevate the legs
Show answer & explanation

Correct answer: D - Position the patient supine and slightly elevate the legs

Question 4

A patient with type 1 diabetes who took insulin but skipped breakfast becomes shaky, confused, and diaphoretic mid-appointment. The assistant should FIRST suspect:

  1. Hyperglycemia from insufficient insulin coverage
  2. A hypertensive crisis triggered by procedural stress
  3. Hypoglycemia from insulin without adequate food
  4. An allergic reaction to the local anesthetic
Show answer & explanation

Correct answer: C - Hypoglycemia from insulin without adequate food

Question 5

Which dental impression material is an irreversible hydrocolloid commonly used to take preliminary impressions for diagnostic study models?

  1. Polyvinyl siloxane
  2. Agar
  3. Polyether
  4. Alginate
Show answer & explanation

Correct answer: D - Alginate

Question 6

A vasoconstrictor such as epinephrine is added to a local anesthetic solution PRIMARILY to:

  1. Prolong the anesthetic's duration and reduce bleeding at the site
  2. Speed the onset so profound numbness is achieved almost instantly
  3. Relax the patient by producing a mild systemic sedative effect
  4. Buffer the cartridge solution by lowering its overall acidity
Show answer & explanation

Correct answer: A - Prolong the anesthetic's duration and reduce bleeding at the site

Question 7

All of the following are muscles of mastication EXCEPT the:

  1. Masseter
  2. Temporalis
  3. Buccinator
  4. Medial pterygoid
Show answer & explanation

Correct answer: C - Buccinator

Domain 3: Clinical Procedures 29.0% of exam

Question 8

Using the clock-concept operating zones for a right-handed operator, the dental assistant is normally seated in the zone corresponding to:

  1. 7 to 12 o'clock
  2. 12 to 2 o'clock
  3. 2 to 4 o'clock
  4. 4 to 7 o'clock
Show answer & explanation

Correct answer: C - 2 to 4 o'clock

Question 9

During cavity preparation, the dentist needs to remove soft, decayed dentin from the tooth. Which hand instrument is designed for this purpose?

  1. Spoon excavator
  2. Amalgam condenser
  3. Periodontal probe
  4. Burnisher
Show answer & explanation

Correct answer: A - Spoon excavator

Question 10

A high-speed handpiece is distinguished from a low-speed handpiece primarily by its:

  1. Latch-type bur attachment and slow, controlled rotation
  2. Rotational speed above 180,000 rpm with a water coolant spray
  3. Routine use for coronal polishing and gross caries removal
  4. Reduced rotation that gives the operator greater tactile control
Show answer & explanation

Correct answer: B - Rotational speed above 180,000 rpm with a water coolant spray

The rest of the RDA blueprint

The RDA exam also covers these domains. Drill them in the full free practice test:

Ready for the real thing?

Practice hundreds more RDA questions with instant scoring, weak-area drills, and full exam simulations.

Start the free practice test See pricing