California RDA Written Exam — Questions and Answers

Question 1: When using the paralleling technique, the cone (PID) is directed perpendicular to the:

Occlusal plane
Both the long axis of the tooth and the receptor (Correct answer)
Receptor only
Long axis of the tooth only

Correct answer: Both the long axis of the tooth and the receptor

In the paralleling technique, the receptor is placed parallel to the tooth's long axis and the PID is directed perpendicular to both.

Question 2: The masseter, temporalis, medial pterygoid, and lateral pterygoid are known as the muscles of:

Facial expression
Deglutition
Mastication (Correct answer)
Tongue movement

Correct answer: Mastication

The four muscles of mastication—masseter, temporalis, medial pterygoid, and lateral pterygoid—are responsible for moving the mandible during chewing. They are all innervated by the mandibular branch (V3) of the trigeminal nerve.

Question 3: After a tooth extraction, the patient is instructed to bite on gauze for 30–45 minutes. The primary reason for this instruction is to:

Apply direct pressure to promote clot formation and hemostasis (Correct answer)
Reduce postoperative swelling
Keep the socket moist so the bone does not dry out
Prevent the tongue from touching the socket

Correct answer: Apply direct pressure to promote clot formation and hemostasis

Direct pressure on the extraction socket compresses the blood vessels and promotes platelet aggregation, which is the first step in hemostasis and clot formation. A stable blood clot is essential for normal healing and prevention of dry socket (alveolar osteitis).

Question 4: What is the purpose of the holding/pre-soak solution used after instrument use but before cleaning?

To achieve sterilization before packaging
To lubricate instruments before autoclaving
To prevent blood and debris from drying on instruments, making cleaning easier and safer (Correct answer)
To disinfect the instruments to a high level

Correct answer: To prevent blood and debris from drying on instruments, making cleaning easier and safer

Holding/pre-soak solutions (enzymatic or neutral pH) prevent blood, saliva, and debris from drying onto instruments, which would harden and make cleaning more difficult and less effective.

Question 5: Which pathway allows an experienced dental assistant without formal training to sit for the DANB RDA exam?

Direct entry pathway
Reciprocity pathway
Work experience pathway (Correct answer)
Military equivalency pathway

Correct answer: Work experience pathway

The work experience pathway allows candidates with sufficient on-the-job hours to qualify for the DANB exam without completing a formal program.

Question 6: What is the primary role of the RDA during intravenous (IV) conscious sedation?

Administer the sedative medications
Monitor patient vital signs and assist the dentist (Correct answer)
Insert the IV catheter
Determine the sedative dosage

Correct answer: Monitor patient vital signs and assist the dentist

During IV conscious sedation, the RDA's role is to monitor the patient's vital signs (blood pressure, pulse, oxygen saturation, respiration) and assist the dentist throughout the procedure.

Question 7: What is the function of the periodontal probe?

Remove supragingival calculus
Contour wax patterns
Measure the depth of the gingival sulcus or periodontal pocket (Correct answer)
Detect caries on tooth surfaces

Correct answer: Measure the depth of the gingival sulcus or periodontal pocket

The periodontal probe is a calibrated instrument used to measure the depth of the gingival sulcus or periodontal pockets in millimeters, aiding in periodontal assessment.

Question 8: Using the Universal Numbering System, what number is assigned to the maxillary left central incisor?

#25
#9 (Correct answer)
#8
#24

Correct answer: #9

In the Universal Numbering System, #9 is the maxillary left central incisor. Numbering begins at #1 (upper right third molar) and goes across the top to #16, then down to #17 and across the bottom to #32.

Question 9: Which of the following is a typical lab duty for a Registered Dental Assistant?

Fabricating dental implants
Creating temporary crowns or impressions (Correct answer)
Administering fluoride treatments
Cleaning the patient's teeth

Correct answer: Creating temporary crowns or impressions

A typical lab duty for a Registered Dental Assistant involves creating temporary crowns or taking impressions. These tasks require precision and knowledge of dental materials to ensure proper fit and function for the patient. RDAs often prepare models from impressions for various dental appliances or restorations.

Question 10: Zinc phosphate cement is mixed on a cool, dry glass slab primarily to:

Prevent moisture contamination
Dissipate the exothermic heat (Correct answer)
Incorporate more powder into the liquid
Accelerate the setting time

Correct answer: Dissipate the exothermic heat

The chemical reaction of mixing zinc phosphate cement is highly exothermic, meaning it releases a significant amount of heat. Mixing on a cool glass slab helps dissipate this heat, which slows down the setting reaction and allows for a longer working time.

Question 11: What is the primary function of a process indicator, such as autoclave tape or markings on a sterilization pouch?

To prove that all microorganisms have been killed
To indicate the expiration date of the sterilized items
To clean the instruments before sterilization
To verify that the instrument package has been exposed to the sterilization process (Correct answer)

Correct answer: To verify that the instrument package has been exposed to the sterilization process

A process indicator changes color when exposed to sterilizing conditions like high heat. Its purpose is to provide immediate visual confirmation that an instrument pack has been through the sterilizer. It does not prove that the instruments inside are sterile; only a biological indicator (spore test) can do that.

Question 12: Which tooth surface faces toward the cheek?

Mesial
Occlusal
Lingual
Buccal (Correct answer)

Correct answer: Buccal

The buccal surface faces the cheek (buccinator muscle). For anterior teeth, the term 'labial' is used instead, referring to the surface facing the lips.

Question 13: What is the purpose of a chemical indicator (CI) placed inside instrument packaging before sterilization?

To indicate that the package was exposed to sterilization conditions (heat, pressure, or chemical) (Correct answer)
To show the instrument is sterile for 30 days
To verify that all microorganisms including spores were killed
To measure the exact temperature inside the sterilizer

Correct answer: To indicate that the package was exposed to sterilization conditions (heat, pressure, or chemical)

Chemical indicators (Type 1–6) change color or form when exposed to sterilization conditions, indicating that the package was processed. They do NOT confirm that sterilization was achieved.

Question 14: Which local anesthetic agent is classified as an amide and is the most commonly used in dentistry?

Tetracaine
Lidocaine (Correct answer)
Procaine
Benzocaine

Correct answer: Lidocaine

Lidocaine (Xylocaine) is an amide-type local anesthetic and is the most widely used local anesthetic in dentistry, often combined with epinephrine as a vasoconstrictor.

Question 15: What document must an RDA submit to the state dental board to demonstrate completion of required continuing education?

Transcripts from dental school
Employment verification letter
CE completion certificates (Correct answer)
Letter of recommendation from a dentist

Correct answer: CE completion certificates

CE completion certificates from approved providers are the standard documentation required by state boards for license renewal.

Question 16: Which personal attribute is important for an RDA to work effectively in a fast-paced environment?

Attention to detail and multitasking skills (Correct answer)
Lack of initiative
Ability to work independently without supervision
Preference for a slow, relaxed pace

Correct answer: Attention to detail and multitasking skills

Attention to detail and multitasking skills are important personal attributes for an RDA working in a fast-paced environment. Dental offices are often busy, requiring RDAs to manage multiple tasks simultaneously, such as preparing instruments, assisting the dentist, and comforting patients, all while maintaining accuracy and efficiency. This ensures smooth operations and high-quality patient care.

Question 17: Which of the following is a common prerequisite before enrolling in a dental assisting program?

Proof of immunizations and health screenings (Correct answer)
Passing a medical licensing exam
Previous certification in dental hygiene
Work experience in a dental office

Correct answer: Proof of immunizations and health screenings

Before enrolling in a dental assisting program, students are commonly required to provide proof of immunizations and undergo health screenings. This prerequisite ensures the safety of both the students and future patients, as dental professionals work in close contact with individuals and handle potentially infectious materials. It helps prevent the spread of communicable diseases within the clinical setting.

Question 18: After removing contaminated gloves, a dental assistant should perform which action first?

Don a new pair of gloves immediately
Apply lotion to prevent skin drying
Wipe hands with a dry paper towel
Perform hand hygiene with soap and water or an alcohol-based hand rub (Correct answer)

Correct answer: Perform hand hygiene with soap and water or an alcohol-based hand rub

Hand hygiene must be performed immediately after removing contaminated gloves because gloves are not impermeable and microorganisms can contaminate hands.

Question 19: Which of the following is classified as a 'critical item' under Spaulding's classification system?

Blood pressure cuff
Dental chair armrests
X-ray cone
Surgical forceps that contact bone (Correct answer)

Correct answer: Surgical forceps that contact bone

Critical items penetrate soft tissue or bone and must be sterilized; surgical forceps that contact bone are a prime example of a critical item.

Question 20: The radiographic error known as 'elongation,' where teeth appear stretched out, is caused by:

Excessive vertical angulation
Placing the film backwards
Insufficient vertical angulation (Correct answer)
Incorrect horizontal angulation

Correct answer: Insufficient vertical angulation

Elongation occurs when the vertical angulation of the x-ray beam is too flat or insufficient. This causes the beam to strike the tooth and film at a shallow angle, projecting a longer, distorted image onto the film.

Question 21: Which cement is most appropriate for the final cementation of a porcelain-fused-to-metal (PFM) crown on a vital tooth?

Calcium hydroxide liner
Zinc phosphate cement
Resin-modified glass ionomer (RMGI) cement (Correct answer)
Zinc oxide eugenol (ZOE)

Correct answer: Resin-modified glass ionomer (RMGI) cement

Resin-modified glass ionomer (RMGI) cement is widely used for final crown cementation because it provides good adhesion, fluoride release, low solubility, biocompatibility, and reduced postoperative sensitivity compared to zinc phosphate.

Question 22: Which instrument is included in a basic examination tray setup?

Matrix retainer and band
Amalgam condenser and carver
Mouth mirror, explorer, and periodontal probe (Correct answer)
Dental dam forceps

Correct answer: Mouth mirror, explorer, and periodontal probe

The basic examination (diagnostic) tray setup always includes a mouth mirror (indirect vision), explorer (caries detection), and periodontal probe (pocket depth measurement), along with cotton pliers.

Question 23: Which type of glove is NOT acceptable for use during patient examination and treatment procedures in dentistry?

Nitrile examination gloves
Household utility gloves used for patient care (Correct answer)
Latex examination gloves
Vinyl examination gloves

Correct answer: Household utility gloves used for patient care

Household utility gloves are intended for cleaning and disinfection tasks, not patient care; using them for treatment would be inappropriate and violate infection control standards.

Question 24: How often should spore testing (biological monitoring) of sterilizers be performed in a dental office?

Weekly (Correct answer)
Monthly
Annually
Daily

Correct answer: Weekly

The CDC and OSAP recommend that dental offices perform spore testing at least weekly to verify sterilizer performance, as well as after any sterilizer repair or malfunction.

Question 25: A significant disadvantage of using a chemical vapor sterilizer is that it:

Requires special ventilation (Correct answer)
Requires a very long sterilization cycle time
Cannot sterilize handpieces
Causes significant rust and corrosion on instruments

Correct answer: Requires special ventilation

Chemical vapor sterilizers use a combination of chemicals, heat, and pressure, which creates hazardous fumes. Therefore, they require special and adequate ventilation to protect the dental team from exposure to these chemicals. This is a primary safety and installation consideration.

Question 26: What is the first step in processing contaminated dental instruments after they are brought to the sterilization center?

Placing them in the ultrasonic cleaner
Placing them in a holding solution (Correct answer)
Running them through the autoclave
Packaging them for sterilization

Correct answer: Placing them in a holding solution

The first step is to place the instruments in a holding solution (presoaking) if they cannot be cleaned immediately. This prevents bioburden like blood and saliva from drying on the instruments, which makes the subsequent cleaning step in an ultrasonic cleaner or instrument washer much more effective and safer.

Question 27: According to CDC guidelines, when should a dental assistant change gloves during patient care?

At the end of each workday
Only when gloves become visibly torn or punctured
Between every patient and whenever gloves are torn or contaminated (Correct answer)
Only when moving from a contaminated to a clean area within the same patient treatment

Correct answer: Between every patient and whenever gloves are torn or contaminated

Gloves must be changed between every patient and whenever they become torn, punctured, or otherwise compromised to prevent cross-contamination.

Question 28: What is the primary function of applying a topical anesthetic before administering a local anesthetic injection?

To disinfect the injection site
To numb the surface tissue for patient comfort during needle insertion (Correct answer)
To act as a vasoconstrictor and reduce bleeding
To achieve profound, deep anesthesia of the tooth

Correct answer: To numb the surface tissue for patient comfort during needle insertion

Topical anesthetic is applied to the surface of the mucous membrane to desensitize the area where the needle will penetrate. This significantly reduces the initial pain or 'pinch' of the injection, improving patient comfort.

Question 29: According to CDC guidelines, what should be done with a sterilizer that fails a spore test?

Continue using the sterilizer and retest next week
Discard all instruments processed by that sterilizer permanently
Remove from service, investigate the failure, have it repaired/serviced, and recall items processed since the last negative test (Correct answer)
Increase the sterilization time and retest

Correct answer: Remove from service, investigate the failure, have it repaired/serviced, and recall items processed since the last negative test

A failed spore test requires immediate removal of the sterilizer from service, investigation of the failure, professional servicing, and recall of all items sterilized since the last confirmed negative test.

Question 30: Which radiographic technique uses a film/sensor holder with an aiming ring to align the central ray perpendicular to the film?

Occlusal technique
Bisecting angle technique
Paralleling technique (Correct answer)
Panoramic technique

Correct answer: Paralleling technique

The paralleling technique uses XCP (Extension Cone Paralleling) instruments or similar film holders with indicator rings to ensure the film/sensor is parallel to the long axis of the tooth and the central ray is perpendicular.

Question 31: What condition describes teeth that overlap horizontally, where the upper anterior teeth protrude beyond the lower anteriors?

Overbite
Overjet (Correct answer)
Open bite
Crossbite

Correct answer: Overjet

Overjet is the horizontal distance between the labial surface of the maxillary incisors and the labial surface of the mandibular incisors, measured parallel to the occlusal plane.

Question 32: What is the purpose of the dental dam during restorative procedures?

To retract soft tissues for better visibility only
To apply topical fluoride
To isolate the operative field from saliva and provide moisture control (Correct answer)
To reduce patient anxiety

Correct answer: To isolate the operative field from saliva and provide moisture control

The dental dam (rubber dam) isolates one or more teeth from the oral environment, preventing moisture contamination (saliva, blood, crevicular fluid) and protecting the airway from small instruments or materials.

Question 33: What is the correct term for the biting surface of posterior teeth?

Incisal
Buccal
Occlusal (Correct answer)
Labial

Correct answer: Occlusal

The occlusal surface is the chewing (biting) surface of posterior teeth (premolars and molars). For anterior teeth, the equivalent surface is called the incisal edge.

Question 34: Which cusp is considered the 'stamp cusp' of the maxillary first premolar?

Lingual cusp (Correct answer)
Buccal cusp
Mesial cusp
Distal cusp

Correct answer: Lingual cusp

The lingual cusp of the maxillary first premolar is the stamp cusp — it occludes in the central fossa of the mandibular first premolar and is the primary functional cusp in centric occlusion.

Question 35: An RDA is responsible for maintaining the dental unit waterlines. What is the primary reason for flushing waterlines at the start of each day?

To warm the water to a comfortable temperature
To remove mineral deposits from the lines
To reduce microbial contamination from overnight stagnation (Correct answer)
To test water pressure before patient treatment

Correct answer: To reduce microbial contamination from overnight stagnation

Flushing waterlines each morning reduces microbial biofilm that accumulates during periods of stagnation, protecting patient and staff safety.

Question 36: Which vasoconstrictior is most commonly combined with local anesthetics in dentistry?

Levonordefrin
Phenylephrine
Norepinephrine
Epinephrine (Correct answer)

Correct answer: Epinephrine

Epinephrine is the most commonly used vasoconstrictor in dental local anesthetics, typically in concentrations of 1:50,000 or 1:100,000.

Question 37: If a dentist asks an RDA to perform a task that is outside their legal scope of practice, what is the most appropriate action for the RDA to take?

Ask another assistant to perform the task
Perform the task only if no patients are watching
Inform the dentist that the task is outside their legal scope of practice and decline to perform it (Correct answer)
Perform the task but document that the dentist requested it

Correct answer: Inform the dentist that the task is outside their legal scope of practice and decline to perform it

RDAs have a professional and legal responsibility to know and adhere to their state's scope of practice. Performing an illegal function can lead to loss of licensure for the RDA and disciplinary action for the dentist. The correct action is to politely and firmly decline, stating that the task is not legally permissible.

Question 38: What radiographic error appears as a cone-shaped radiopaque shadow on the periapical image?

Overlapping
Elongation
Cone cutting (Correct answer)
Film/sensor bending

Correct answer: Cone cutting

Cone cutting occurs when the PID (cone) is not aligned correctly and the primary beam misses part of the film/sensor, resulting in a clear (unexposed) area with a cone/circular shape.

Question 39: What is the FIRST action to take when a patient is found unresponsive in the dental chair?

Administer epinephrine
Administer oxygen via nasal cannula
Activate EMS (call 911) and initiate the office emergency protocol (Correct answer)
Begin CPR immediately without checking for responsiveness first

Correct answer: Activate EMS (call 911) and initiate the office emergency protocol

Upon finding an unresponsive patient, immediately activate the emergency medical services (call 911) and initiate the office emergency protocol while another team member assesses the patient.

Question 40: What is the key biological indicator organism used for spore testing a steam autoclave sterilizer?

Geobacillus stearothermophilus (Correct answer)
Staphylococcus aureus
Mycobacterium tuberculosis
Bacillus atrophaeus

Correct answer: Geobacillus stearothermophilus

Geobacillus stearothermophilus is a bacterium that is highly resistant to moist heat, making it the ideal biological indicator for verifying the effectiveness of steam sterilization. If these hardy spores are killed, it provides a high degree of assurance that all other microorganisms have also been destroyed.

Question 41: Which impression material is most affected by the presence of moisture or blood during the impression-taking procedure?

Zinc oxide eugenol (ZOE)
Alginate
Polyvinyl siloxane (PVS) (Correct answer)
Polyether

Correct answer: Polyvinyl siloxane (PVS)

Polyvinyl siloxane (PVS) is hydrophobic and is significantly affected by moisture, blood, or saliva contamination, leading to voids and inaccurate impressions.

Question 42: Which action demonstrates proper four-handed dentistry technique during an anterior composite procedure?

The RDA holds the curing light and activates it before the dentist signals
The RDA steps out during etching to prepare the next patient
The RDA controls the suction and maintains the mirror retraction while the dentist operates (Correct answer)
The RDA applies the bonding agent independently to save time

Correct answer: The RDA controls the suction and maintains the mirror retraction while the dentist operates

In four-handed dentistry, the RDA continuously manages suction and tissue retraction so the dentist can focus without interruption.

Question 43: Which surface barrier is most appropriate to protect the dental unit light handle during patient treatment?

Wearing double gloves so one layer can be removed after touching the light
Spraying the handle with disinfectant spray immediately before seating the patient
Wiping with a dry cloth between patients
A pre-cut plastic wrap or commercially made barrier changed between each patient (Correct answer)

Correct answer: A pre-cut plastic wrap or commercially made barrier changed between each patient

Plastic barriers (wrap or sleeves) placed on the light handle before treatment and discarded between patients prevent cross-contamination without relying on chemical disinfection alone.

Question 44: On a pre-set tray, instruments are typically arranged from left to right in what order?

Smallest to largest
Order of use (Correct answer)
Alphabetical order
Grouped by function (e.g., all carvers together)

Correct answer: Order of use

Instruments on a tray are arranged in the sequence they will be used by the dentist. This ergonomic setup allows the dental assistant to pass instruments efficiently without having to search for the next one, improving the workflow of the procedure.

Question 45: Aluminum filtration is built into the x-ray tube housing primarily to:

Prevent the patient from seeing the x-ray beam during exposure
Reduce electrical interference during exposure
Increase the intensity of the beam to reduce exposure time
Remove low-energy (long-wavelength) x-rays that would increase patient dose without contributing to the diagnostic image (Correct answer)

Correct answer: Remove low-energy (long-wavelength) x-rays that would increase patient dose without contributing to the diagnostic image

Aluminum filtration (inherent and added) removes low-energy photons that would be absorbed by superficial tissues and increase patient dose without penetrating to the receptor. The FDA and ADA require minimum total filtration of 1.5 mm Al equivalent for units up to 70 kVp and 2.5 mm Al for units operating above 70 kVp.

Question 46: A final impression for a full-coverage crown is most commonly taken using a:

Polyvinyl siloxane (PVS) in a custom or triple tray (Correct answer)
Alginate (irreversible hydrocolloid) in a stock tray
Zinc oxide eugenol (ZOE) impression paste
Plaster of Paris in a full-arch tray

Correct answer: Polyvinyl siloxane (PVS) in a custom or triple tray

Polyvinyl siloxane (PVS), also called vinyl polysiloxane, is the standard material for final (definitive) crown and bridge impressions due to its dimensional accuracy, elastic recovery, and tear resistance. Alginate is used for study models and opposing arch impressions, not final prosthetic impressions.

Question 47: What does an automated external defibrillator (AED) do and when should it be used?

It delivers oxygen to a patient in respiratory arrest — use any time a patient is unconscious
It analyzes heart rhythm and delivers an electric shock for ventricular fibrillation or pulseless ventricular tachycardia (Correct answer)
It administers medication automatically — use for anaphylaxis
It measures blood pressure — use for all cardiac emergencies

Correct answer: It analyzes heart rhythm and delivers an electric shock for ventricular fibrillation or pulseless ventricular tachycardia

An AED analyzes the patient's heart rhythm and, if it detects ventricular fibrillation (VF) or pulseless ventricular tachycardia (pVT), advises and delivers a defibrillating shock to restore normal sinus rhythm.

Question 48: Which restorative material undergoes the LEAST thermal expansion and contraction, making it most dimensionally stable in the oral cavity?

Ceramic (porcelain) (Correct answer)
Composite resin
Gold alloy
Amalgam

Correct answer: Ceramic (porcelain)

Ceramic/porcelain has a coefficient of thermal expansion very close to that of natural tooth structure, making it the most dimensionally stable under temperature changes.

Question 49: Which classification of instruments requires sterilization because they penetrate soft tissue or bone?

Critical instruments (Correct answer)
Semicritical instruments
Noncritical instruments
Utility instruments

Correct answer: Critical instruments

Critical instruments (e.g., forceps, elevators, scalers, burs, needles) penetrate soft tissue or bone and must be sterilized (not just disinfected) because they have the highest risk for transmitting infection.

Question 50: What is the minimum education required to become a Registered Dental Assistant (RDA)?

Associate’s degree in any field
Master’s degree in Dental Hygiene
High school diploma or equivalent (Correct answer)
Bachelor’s degree in Dental Science

Correct answer: High school diploma or equivalent

To become a Registered Dental Assistant (RDA), a high school diploma or its equivalent is generally the minimum educational prerequisite. While many pursue post-secondary dental assisting programs, this foundational education is sufficient to begin training. Specific state requirements may vary, but a high school diploma is universally accepted as the basic entry-level education.

Question 51: An RDA is preparing a tray for a composite restoration. Which material should be included for caries removal and cavity preparation?

Zinc oxide eugenol base
High-speed handpiece and burs (Correct answer)
Calcium hydroxide liner
Acid etch gel

Correct answer: High-speed handpiece and burs

A high-speed handpiece with appropriate burs is used during cavity preparation to remove decayed tooth structure before restoration placement.

Question 52: A panoramic radiograph shows the anterior teeth appearing blurry and out of focus. The MOST likely cause is:

Excessive kVp
Patient positioned too far forward in the focal trough (Correct answer)
Patient positioned too far backward in the focal trough
Patient movement of the hands

Correct answer: Patient positioned too far forward in the focal trough

When the patient is positioned too far forward, the anterior teeth are in front of the focal trough, causing them to appear blurry and narrowed.

Question 53: What is the correct position for an unconscious patient who is breathing but has no suspected spinal injury?

Supine (flat on back)
Semi-reclined (30 degrees)
Recovery position (lateral recumbent) (Correct answer)
Trendelenburg (supine with feet elevated)

Correct answer: Recovery position (lateral recumbent)

An unconscious but breathing patient without suspected spinal injury should be placed in the recovery (lateral) position to protect the airway from obstruction by the tongue and aspiration of vomit.

Question 54: What is the purpose of applying a cavity varnish before placing an amalgam restoration?

To improve the color match of the restoration
To reduce microleakage and protect the pulp from irritants (Correct answer)
To increase the strength of the amalgam
To bond the amalgam to the tooth structure

Correct answer: To reduce microleakage and protect the pulp from irritants

Cavity varnish seals dentinal tubules to reduce microleakage and protects the pulp from chemical irritants until the amalgam has fully set.

Question 55: How should an RDA handle a patient who is nervous about a procedure?

Ask the patient to leave the office
Rush through the procedure to get it over with
Explain the procedure calmly and provide reassurance (Correct answer)
Ignore the patient's anxiety

Correct answer: Explain the procedure calmly and provide reassurance

When a patient is nervous about a procedure, an RDA should explain the procedure calmly and provide reassurance. This approach helps alleviate anxiety by demystifying the process and offering emotional support. Clear communication and a compassionate demeanor build trust and make the patient feel more comfortable and informed.

Question 56: Which type of alginate impression material error results in a grainy or rough surface texture on the model?

Insufficient mixing time resulting in unmixed alginate particles (Correct answer)
Using too little water in the mix
Syneresis occurring after impression removal
Pouring the model too quickly

Correct answer: Insufficient mixing time resulting in unmixed alginate particles

Insufficient mixing (undermixing) leaves unmixed alginate particles that produce a grainy, rough texture on the surface of the poured model.

Question 57: The State Dental Board has the authority to take which action against a dental assistant who violates the Dental Practice Act?

Impose prison sentences
Suspend or revoke the assistant's license or certificate (Correct answer)
Order the employer to terminate the assistant
File a criminal indictment

Correct answer: Suspend or revoke the assistant's license or certificate

The State Dental Board can suspend, revoke, or place conditions on a dental assistant's license or certificate for violations of the Dental Practice Act.

Question 58: A parent calls to inquire about their 17-year-old child's dental treatment. Under HIPAA, when can the dental office share this information without the minor's consent?

When the parent is the legal guardian and the minor has not requested confidentiality (Correct answer)
Only if the minor is being treated for a communicable disease
Never — minors always have full privacy rights
Only after the treating dentist approves each request

Correct answer: When the parent is the legal guardian and the minor has not requested confidentiality

Parents who are legal guardians generally have access to a minor's health records unless an exception applies, such as emancipation or treatment for sensitive services.

Question 59: An impression is removed from the mouth and a void is found at the margin of the preparation. Which of the following is the MOST likely cause?

Air was trapped during syringing of light-body material (Correct answer)
The patient opened their mouth too wide
Impression material was too viscous
The tray was removed too quickly

Correct answer: Air was trapped during syringing of light-body material

Voids at critical margin areas are most commonly caused by air entrapment during injection of the light-body material around the preparation.

Question 60: What is the purpose of bonding agent in composite resin restorations?

To etch the enamel before acid application
To act as a base protecting the pulp
To chemically bond the composite resin to acid-etched enamel and/or dentin (Correct answer)
To block dentinal tubules from sensitivity only

Correct answer: To chemically bond the composite resin to acid-etched enamel and/or dentin

Bonding agents (adhesives) form a chemical and micromechanical bond between composite resin and the acid-etched tooth structure (enamel and/or dentin), creating a durable interface that resists microleakage.

Question 61: What is the minimum contact time required for most intermediate-level surface disinfectants to be effective?

The wet contact time specified on the product label (usually 1–10 minutes) (Correct answer)
10 seconds
24 hours
30 seconds

Correct answer: The wet contact time specified on the product label (usually 1–10 minutes)

Disinfectants must remain wet on a surface for the contact time listed on their EPA-registered label to achieve the claimed level of disinfection.

Question 62: Respiratory hygiene and cough etiquette in the dental waiting room includes which of the following?

Asking all patients to wear N95 respirators upon entry
Separating all patients with coughs into negative-pressure rooms
Providing tissues, no-touch waste containers, and hand hygiene supplies at the front desk (Correct answer)
Requiring patients to use antimicrobial mouthrinse only

Correct answer: Providing tissues, no-touch waste containers, and hand hygiene supplies at the front desk

Providing tissues, waste containers, and hand hygiene resources at the point of patient entry is the CDC-recommended respiratory hygiene strategy for preventing respiratory infection spread.

Question 63: A patient bites through an alginate impression before it has fully set. What is the MOST likely result?

The impression will be unaffected
Permanent deformation and inaccurate reproduction of the arch (Correct answer)
The alginate will re-flow and self-correct
The material will set faster due to pressure

Correct answer: Permanent deformation and inaccurate reproduction of the arch

Applying pressure to alginate during gelation causes permanent deformation (tearing or distortion) because the material cannot recover elastically until fully set.

Question 64: What is the correct first step in instrument reprocessing after use?

Sterilization
Ultrasonic cleaning or scrubbing
Transport to the sterilization area in a covered container (Correct answer)
Packaging

Correct answer: Transport to the sterilization area in a covered container

The first step is safely transporting used instruments in a covered, puncture-resistant container to the sterilization area to prevent occupational exposure during transport.

Question 65: During an orthodontic appointment, a dental assistant uses a scaler to remove excess bonding material around a newly placed bracket. This instrument technique is called:

Band seating
Torquing
Coronal polishing
Flash removal (Correct answer)

Correct answer: Flash removal

After brackets are bonded to teeth, excess adhesive ('flash') that squeezes out from under the bracket base must be removed before the bonding agent is light-cured or while it is still pliable. This process is called flash removal and is a routine expanded duty in orthodontic assisting.

Question 66: During a procedure, a patient with a known history of diabetes becomes confused, irritable, and their skin is cold and clammy. What should be administered immediately?

An oxygen mask
A glass of water
A source of concentrated sugar, like glucose gel (Correct answer)
Nitroglycerin

Correct answer: A source of concentrated sugar, like glucose gel

These symptoms are indicative of hypoglycemia, or low blood sugar. The immediate treatment is to provide a readily available source of sugar, such as glucose gel, orange juice, or non-diet soda, to quickly raise their blood glucose levels.

Question 67: Which category of personal protective equipment (PPE) must be worn by dental assistants during all procedures that may generate aerosols or splatter?

Gloves, mask, protective eyewear, and gown (Correct answer)
Mask and gloves only
Gloves only
Gown and gloves only

Correct answer: Gloves, mask, protective eyewear, and gown

OSHA requires gloves, mask, protective eyewear, and a gown (or clinic attire) during procedures generating aerosols or splatter to protect from blood-borne pathogens and infectious materials.

Question 68: Which type of gypsum product is used to construct dies for crown and bridge fabrication due to its high compressive strength and minimal setting expansion?

Die stone (Type IV) (Correct answer)
Plaster of Paris (Type I)
Impression plaster (Type II)
Dental stone (Type III)

Correct answer: Die stone (Type IV)

Type IV die stone (high-strength stone) has the greatest compressive strength and lowest setting expansion, making it ideal for accurate die fabrication.

Question 69: What is the legal duty of the dental team regarding suspected child abuse or neglect in California?

Report only if the child directly discloses abuse
Report only if injuries are in the oral cavity
Consult with the dentist and decide as a team whether to report
Dental professionals are mandated reporters and must report reasonable suspicion of child abuse to Child Protective Services (CPS) or law enforcement (Correct answer)

Correct answer: Dental professionals are mandated reporters and must report reasonable suspicion of child abuse to Child Protective Services (CPS) or law enforcement

Dental professionals in California are mandated reporters under Penal Code §11166. They must report reasonable suspicion of child abuse or neglect to Child Protective Services or law enforcement — they do not need proof, only reasonable suspicion.

Question 70: What is the purpose of the lead apron and thyroid collar during dental radiography?

To reduce the radiation dose to the dentist
To prevent scatter radiation from exposing the patient's gonads and thyroid gland (Correct answer)
To improve image quality
To prevent electrical shock from the x-ray unit

Correct answer: To prevent scatter radiation from exposing the patient's gonads and thyroid gland

The lead apron protects the patient's gonads and torso from scatter radiation, while the thyroid collar specifically protects the thyroid gland, which is particularly sensitive to radiation.

Question 71: The non-functional, fifth cusp often found on the mesiolingual surface of a permanent maxillary first molar is called the:

Mamelon
Cingulum
Cusp of Carabelli (Correct answer)
Talon cusp

Correct answer: Cusp of Carabelli

The Cusp of Carabelli is a supplementary, non-functional cusp located on the mesiolingual surface of the maxillary first molar. While not present on every individual, its presence is a common morphological trait for this specific tooth.

Question 72: Which statement about latex allergy in the dental setting is correct?

Latex allergy only affects dental staff, never patients
Dental teams must be prepared to manage latex allergy reactions and offer latex-free alternatives (Correct answer)
Type IV latex hypersensitivity is the most life-threatening reaction type
Latex gloves are still the preferred choice because of superior barrier protection

Correct answer: Dental teams must be prepared to manage latex allergy reactions and offer latex-free alternatives

Both patients and staff can have latex allergies, so dental offices must stock latex-free alternatives (nitrile, vinyl) and have protocols to manage allergic reactions.

Question 73: What is the correct temperature and time for a gravity displacement steam autoclave to achieve sterilization of unwrapped instruments?

270°F (132°C) for 3 minutes
180°F (82°C) for 30 minutes
320°F (160°C) for 60 minutes
250°F (121°C) for 15–30 minutes (Correct answer)

Correct answer: 250°F (121°C) for 15–30 minutes

Gravity displacement steam autoclaves sterilize at 250°F (121°C) for 15–30 minutes (depending on load type). Pre-vacuum autoclaves operate at 270°F (132°C) for shorter cycles.

Question 74: An RDA moves from California to Texas. Which step is required before practicing in Texas?

Retake the DANB exam from scratch
Request a temporary permit from DANB
Apply for reciprocity automatically
Meet Texas-specific licensure requirements (Correct answer)

Correct answer: Meet Texas-specific licensure requirements

Dental assistant licensure is state-specific, so the RDA must satisfy Texas's own application, exam, and fee requirements.

Question 75: In accordance with universal safety standards, what colors are the compressed gas cylinders for oxygen and nitrous oxide, respectively?

Blue, Green
Yellow, Blue
Green, Blue (Correct answer)
Green, Gray

Correct answer: Green, Blue

The universal color-coding system is a critical safety feature to prevent accidental mix-ups of medical gases. Oxygen cylinders are always green (in the US), and nitrous oxide cylinders are always blue.

Question 76: The Stensen's duct, which carries saliva from the parotid gland into the mouth, opens opposite which teeth?

Mandibular central incisors
Maxillary first and second premolars
Mandibular canines
Maxillary first and second molars (Correct answer)

Correct answer: Maxillary first and second molars

Stensen's duct (parotid duct) opens into the oral vestibule opposite the maxillary first and second molars on the buccal mucosa. The papilla is called the parotid papilla. Knowing this landmark is important when placing cotton rolls and during intraoral examination.

Question 77: Dry heat sterilization is the most appropriate method for which type of dental instrument?

Orthodontic pliers and carbon steel burs (Correct answer)
Wet gauze packs
Heat-sensitive rubber items
Plastic impression trays

Correct answer: Orthodontic pliers and carbon steel burs

Dry heat sterilization uses high temperature without moisture, which can cause rust or corrosion. This makes it the ideal method for instruments that are sensitive to moisture, such as carbon steel instruments, burs, and orthodontic pliers, as it prevents them from dulling and corroding.

Question 78: What is the correct procedure for disposing of a used local anesthetic needle?

Recap using a one-handed scoop technique, then place in sharps container (Correct answer)
Break the needle before disposal
Recap with two hands and place in regular trash
Place uncapped directly into a sharps container

Correct answer: Recap using a one-handed scoop technique, then place in sharps container

The correct procedure is the one-handed scoop technique for recapping, then disposing of the capped needle in an approved sharps container to prevent needlestick injury.

Question 79: Which of the following is an essential interpersonal skill for an RDA?

Advanced surgical skills
Strong communication and empathy (Correct answer)
Ability to handle bookkeeping
Knowledge of software coding

Correct answer: Strong communication and empathy

Strong communication and empathy are essential interpersonal skills for an RDA. They frequently interact with patients, explaining procedures, answering questions, and providing reassurance, especially to anxious individuals. Empathy helps RDAs understand and address patient concerns, fostering a more comfortable and trusting environment.

Question 80: What does the concept of 'informed consent' require before dental treatment?

Consent is implied when a patient enters a dental office
The patient's signature on a general office intake form only
The patient must be told and understand the proposed treatment, its risks, benefits, alternatives, and the risk of no treatment, and must voluntarily agree (Correct answer)
Only the dentist needs to explain the treatment — assistants are not involved

Correct answer: The patient must be told and understand the proposed treatment, its risks, benefits, alternatives, and the risk of no treatment, and must voluntarily agree

Informed consent requires that the patient be provided with complete information about proposed treatment (including risks, benefits, and alternatives), understand it, and voluntarily agree before treatment begins.

Question 81: What medication should the dental team have available and administer to a conscious patient experiencing angina pectoris?

Diphenhydramine 50 mg oral
Aspirin 325 mg oral
Nitroglycerin 0.3–0.4 mg sublingual (Correct answer)
Epinephrine 1:1,000 IM

Correct answer: Nitroglycerin 0.3–0.4 mg sublingual

For angina pectoris, nitroglycerin 0.3–0.4 mg sublingual (spray or tablet) is administered to dilate coronary arteries and relieve ischemic chest pain within 1–3 minutes.

Question 82: What percentage of oxygen is included in a nitrous oxide/oxygen sedation mixture at minimum?

20% (Correct answer)
50%
30%
10%

Correct answer: 20%

The minimum oxygen concentration in a nitrous oxide/oxygen sedation mixture is 20% (equal to or greater than atmospheric oxygen), ensuring the patient does not experience hypoxia.

Question 83: Which type of impression material is used for final impressions of crown and bridge preparations due to its high dimensional accuracy?

Polyvinyl siloxane (PVS/addition silicone) (Correct answer)
Alginate (irreversible hydrocolloid)
Zinc oxide eugenol (ZOE)
Compound (thermoplastic)

Correct answer: Polyvinyl siloxane (PVS/addition silicone)

Polyvinyl siloxane (PVS, addition-cured silicone) provides excellent dimensional stability, high detail reproduction, and can be poured multiple times, making it the material of choice for crown and bridge final impressions.

Question 84: Under most State Dental Practice Acts, which of the following functions is considered an EXPANDED function that requires specific delegation and training?

Seating and dismissing patients
Placing and finishing composite restorations (Correct answer)
Taking vital signs
Exposing radiographs under general supervision

Correct answer: Placing and finishing composite restorations

Placing and finishing composite restorations is typically an expanded function that requires additional training and explicit delegation by the dentist.

Question 85: What bur is most commonly used to prepare the initial entry into enamel during cavity preparation?

Round bur #2
Tapered fissure bur (Correct answer)
Inverted cone bur
Pear-shaped bur

Correct answer: Tapered fissure bur

A tapered fissure carbide bur is most commonly used for cavity preparation entry, especially for creating the initial access outline form and vertical walls in Class I and Class II preparations.

Question 86: When preparing an amalgam restoration, the dental assistant mixes the amalgam and notices it is crumbly and dry. What is the MOST likely cause?

Undertrituration (Correct answer)
Using too much mercury
Contamination with water
Overtrituration

Correct answer: Undertrituration

Undertrituration results in insufficient mercury-alloy contact, producing a crumbly, grainy mix with reduced strength and poor adaptation.

Question 87: What property of polyether impression material makes it advantageous in humid clinical conditions?

It is highly hydrophobic
It requires no mixing
It is hydrophilic and wets oral tissues well (Correct answer)
It releases fluoride during setting

Correct answer: It is hydrophilic and wets oral tissues well

Polyether is hydrophilic, which allows it to flow into moist sulcular areas and wet oral tissues effectively, producing detailed impressions even in humid conditions.

Question 88: A dental assistant overhears a colleague falsely telling a patient that another dentist in town was disciplined for malpractice. This could constitute which tort?

Battery
Defamation (slander) (Correct answer)
Assault
Invasion of privacy

Correct answer: Defamation (slander)

Making false spoken statements that damage another person's reputation is slander, a form of defamation.

Question 89: What is the purpose of the matrix band and retainer during an amalgam restoration?

To etch the tooth surface
To isolate the tooth from saliva
To apply bonding agent
To create a temporary wall replacing the missing tooth wall during restoration placement (Correct answer)

Correct answer: To create a temporary wall replacing the missing tooth wall during restoration placement

A matrix band and retainer (such as the Tofflemire retainer) create a temporary interproximal wall, providing a form to condense amalgam against when one or more walls of the cavity preparation are missing.

Question 90: What does 'res ipsa loquitur' mean in the context of dental malpractice?

The dentist had no duty of care
The patient assumes all risks
The thing speaks for itself — negligence is obvious from the injury (Correct answer)
Both parties share equal fault

Correct answer: The thing speaks for itself — negligence is obvious from the injury

Res ipsa loquitur is a legal doctrine meaning the injury itself is evidence of negligence without need for expert testimony.

Question 91: During root canal therapy, a rubber dam is placed primarily to:

Reduce the amount of anesthetic needed
Isolate the field and prevent contamination of the canal with oral bacteria (Correct answer)
Retract the cheek for better operator visibility
Improve patient comfort by keeping the mouth open

Correct answer: Isolate the field and prevent contamination of the canal with oral bacteria

The rubber dam isolates the tooth being treated, keeping saliva and oral bacteria out of the root canal system. Endodontic success depends on achieving and maintaining asepsis throughout the procedure. The rubber dam is considered mandatory for safe endodontic treatment.

Question 92: When a patient signs an informed consent form, what must they be told to make the consent legally valid?

The nature of the procedure, risks, benefits, and alternatives (Correct answer)
That all dental procedures are risk-free
The dentist's educational credentials
Only the cost of the procedure

Correct answer: The nature of the procedure, risks, benefits, and alternatives

Valid informed consent requires disclosure of the procedure, its material risks and benefits, and available alternatives so the patient can make an informed decision.

Question 93: Before applying a resin-based pit-and-fissure sealant, the tooth surface is conditioned with phosphoric acid gel. The purpose of acid etching is to:

Create a microscopically roughened surface that increases mechanical retention of the sealant (Correct answer)
Remove intrinsic stains from the fissures
Remineralize early enamel lesions before sealing
Kill bacteria remaining in the pit after cleaning

Correct answer: Create a microscopically roughened surface that increases mechanical retention of the sealant

Phosphoric acid (typically 37%) creates microscopic porosities in enamel by selectively dissolving hydroxyapatite crystals. When the liquid sealant flows into these micro-porosities and cures, resin tags form, providing micromechanical retention. Without etching, bond strength would be insufficient.

Question 94: When instructing a patient on the Bass toothbrushing technique, the dental assistant should direct the patient to angle the brush bristles at approximately:

45 degrees toward the gingival margin (Correct answer)
0 degrees (parallel to the occlusal plane)
30 degrees toward the gingival margin
90 degrees perpendicular to the tooth surface

Correct answer: 45 degrees toward the gingival margin

The Bass technique places the bristles at a 45-degree angle to the gingival margin so they penetrate slightly into the gingival sulcus and disrupt subgingival plaque. This makes it effective for patients with gingivitis or periodontal disease. The bristles are then vibrated with short back-and-forth strokes.

Question 95: Which document governs an RDA's legal scope of practice in the United States?

The OSHA Bloodborne Pathogens Standard
The Dental Practice Act of the state in which they work (Correct answer)
The National Board Dental Examination guidelines
The ADA Code of Professional Conduct

Correct answer: The Dental Practice Act of the state in which they work

Each state's Dental Practice Act defines the procedures RDAs are legally permitted to perform within that jurisdiction.

Question 96: Which method of sterilization is preferred for oil-based materials, petroleum-based products, and materials that are damaged by moisture?

Steam autoclave
Ethylene oxide
Chemical vapor (chemiclave)
Dry heat oven (Correct answer)

Correct answer: Dry heat oven

Dry heat sterilization is preferred for oils, petroleum-based products, and moisture-sensitive instruments because it uses high temperature dry air without moisture that could cause corrosion or product breakdown.

Question 97: Which topical anesthetic agent is most commonly used in dental offices prior to needle insertion?

Benzocaine 20% (Correct answer)
Bupivacaine 0.5%
Mepivacaine 3%
Lidocaine 2% with epinephrine

Correct answer: Benzocaine 20%

Benzocaine 20% gel is the most widely used topical anesthetic in dentistry for reducing discomfort prior to needle penetration.

Question 98: During a procedure, the dentist asks the RDA to transfer instruments using the single-handed transfer technique. Where should the RDA position the instrument for handoff?

Directly over the patient's chest
In the dentist's dominant hand, below their line of sight
On the bracket tray for the dentist to pick up
At the exchange zone near the patient's chin (Correct answer)

Correct answer: At the exchange zone near the patient's chin

The exchange zone near the patient's chin keeps instrument transfers within the dentist's peripheral vision and reduces movement fatigue.

Question 99: A processed radiograph that appears too dark (high in density) is likely the result of:

Fixer solution contamination
Excessive exposure time or overdevelopment (Correct answer)
Insufficient exposure time
Underdevelopment or cool developer

Correct answer: Excessive exposure time or overdevelopment

An overly dark radiograph indicates that the film's silver halide crystals received too much exposure or were over-processed. This can be caused by excessive exposure time, kVp, or mA, or by leaving the film in the developer solution for too long or at too high a temperature.

Question 100: Which bone forms the posterior portion of the hard palate?

Sphenoid bone
Maxilla
Palatine bone (Correct answer)
Vomer

Correct answer: Palatine bone

The hard palate is formed by two bones: the palatine processes of the maxilla (anterior two-thirds) and the horizontal plates of the paired palatine bones (posterior one-third). The vomer forms the nasal septum, not the palate.

Question 101: Which biological indicator is used to verify steam autoclave sterilization efficacy?

Bacillus atrophaeus spore strips
Bacillus cereus spore strips
Clostridium tetani spore strips
Geobacillus stearothermophilus spore strips (Correct answer)

Correct answer: Geobacillus stearothermophilus spore strips

Geobacillus stearothermophilus (formerly Bacillus stearothermophilus) spore strips are the biological indicator for steam autoclave validation, as these spores are highly resistant to moist heat.

Question 102: What is the primary purpose of a vasoconstrictor, such as epinephrine, in a local anesthetic solution?

To prolong the duration of the anesthetic effect (Correct answer)
To reduce the pain of the injection
To prevent an allergic reaction
To buffer the pH of the solution

Correct answer: To prolong the duration of the anesthetic effect

A vasoconstrictor narrows the blood vessels at the injection site. This reduces bleeding, slows the absorption of the anesthetic into the bloodstream (decreasing potential toxicity), and prolongs its numbing effect.

Question 103: What causes a herringbone (tire-track) pattern artifact on a dental radiograph?

Film was processed in depleted developer
Film was double-exposed
Film was placed backward in the patient's mouth (Correct answer)
Film was bent during exposure

Correct answer: Film was placed backward in the patient's mouth

A herringbone (tire-track or reverse pattern) artifact appears when the film is placed backward (with the lead foil side facing the X-ray source), causing the embossed pattern of the foil backing to be imprinted on the image.

Question 104: What does it mean when a sterilization pouch has an external chemical indicator that has NOT changed color?

The package should be re-sterilized immediately
The chemical indicator is defective
The package may NOT have been exposed to sterilization conditions and should NOT be used (Correct answer)
The package is sterile and safe to use

Correct answer: The package may NOT have been exposed to sterilization conditions and should NOT be used

If the external chemical indicator has NOT changed color, the package may not have been exposed to sterilization conditions and should not be used on a patient until it has been properly processed and the indicator has changed.

Question 105: What technique error causes the teeth to appear shorter than their actual length on a periapical radiograph?

Foreshortening (Correct answer)
Cone cutting
Elongation
Overlapping

Correct answer: Foreshortening

Foreshortening occurs when the vertical angulation of the X-ray beam is excessive (too steep), causing the teeth to appear shorter than their actual length.

Question 106: What information must be included on sterilization packaging before processing?

Technician initials only
Instrument list only
Patient name only
Date of sterilization, sterilizer number/identifier, and load/cycle number (Correct answer)

Correct answer: Date of sterilization, sterilizer number/identifier, and load/cycle number

Sterilization packages must be labeled with the date, sterilizer ID (if multiple units), and load/cycle number to enable traceability and proper event-related sterility maintenance protocols.

Question 107: Which duty is within the scope of practice for a Registered Dental Assistant in most US states?

Prescribing fluoride treatments
Diagnosing dental caries
Performing coronal polishing after training and certification (Correct answer)
Interpreting radiographs independently

Correct answer: Performing coronal polishing after training and certification

Coronal polishing is a delegable expanded function that RDAs can legally perform in most states after completing required training.

Question 108: A dental office uses a patient's before-and-after photos in a social media marketing post without written consent. This is a violation of which principle?

Nonmaleficence
Beneficence
Standard of care
Patient confidentiality and HIPAA privacy rules (Correct answer)

Correct answer: Patient confidentiality and HIPAA privacy rules

Using identifiable patient photos without written authorization violates HIPAA's Privacy Rule and patient confidentiality rights.

Question 109: Which of the following actions would be considered a violation of HIPAA and a breach of patient confidentiality?

Consulting with another dentist in the practice about a patient's case
Discussing a patient's treatment in the office reception area (Correct answer)
Calling a patient by their first name in the operatory
Using a patient's chart to file an insurance claim

Correct answer: Discussing a patient's treatment in the office reception area

Patient confidentiality is a cornerstone of healthcare ethics and law (HIPAA). Discussing any patient's protected health information (PHI), including their treatment plan, in a public area like a reception room where it can be overheard by others is a clear violation of their privacy.

Question 110: Which category of drugs can cause gingival hyperplasia (overgrowth of gum tissue) as a side effect, requiring close attention during periodontal assessment?

Calcium channel blockers (e.g., nifedipine) (Correct answer)
ACE inhibitors (e.g., lisinopril)
Diuretics (e.g., furosemide)
Beta-blockers (e.g., metoprolol)

Correct answer: Calcium channel blockers (e.g., nifedipine)

Calcium channel blockers—particularly nifedipine (used for hypertension and angina)—are well-known to cause drug-induced gingival hyperplasia in some patients. Other drugs with this side effect include phenytoin (seizure medication) and cyclosporine (immunosuppressant). The dental team must document all current medications at every appointment.

Question 111: A patient requests copies of their dental records before transferring to a new dentist. Under HIPAA, the dental office must provide the records within how many days?

15 days
90 days
30 days (Correct answer)
60 days

Correct answer: 30 days

HIPAA requires covered entities to provide patients access to their health records within 30 days of the request.

Question 112: An RDA is setting up for a patient who requires antibiotic premedication. When should the antibiotic ideally be taken?

The night before the appointment
30 to 60 minutes before the procedure (Correct answer)
Immediately upon arriving at the dental office
After the procedure is completed

Correct answer: 30 to 60 minutes before the procedure

AHA guidelines recommend antibiotic premedication be taken 30–60 minutes before the dental procedure to achieve adequate serum levels during treatment.

Question 113: What is the typical length of an accredited dental assisting program leading to RDA eligibility?

9–11 months (Correct answer)
3–6 months
18–24 months
3–4 years

Correct answer: 9–11 months

Most CODA-accredited dental assisting programs are approximately one academic year (9–11 months) in length.

Question 114: Which emergency drug is used to treat anaphylaxis in the dental office?

Diphenhydramine
Nitroglycerin
Aspirin
Epinephrine (1:1,000) (Correct answer)

Correct answer: Epinephrine (1:1,000)

Epinephrine 1:1,000 (0.3–0.5 mg IM) is the first-line treatment for anaphylaxis. It reverses bronchospasm, vasodilation, and hypotension — the life-threatening components of anaphylactic shock.

Question 115: What is the primary purpose of a state's Dental Practice Act?

To protect the public from incompetent or unethical dental practitioners (Correct answer)
To set the fee schedules for dental procedures
To ensure all dental assistants are paid a minimum wage
To promote the business interests of dentists

Correct answer: To protect the public from incompetent or unethical dental practitioners

A state's Dental Practice Act is the body of law that legally defines the practice of dentistry in that state. Its foremost purpose is to protect the public by setting standards for licensure, defining the scope of practice for all dental professionals, and outlining grounds for discipline.

Question 116: Which type of elastomeric impression material is known for having the best dimensional stability over time, allowing a delay before pouring the model?

Polyvinyl siloxane (PVS) (Correct answer)
Condensation silicone
Polyether
Polysulfide

Correct answer: Polyvinyl siloxane (PVS)

Polyvinyl siloxane (PVS) has excellent dimensional stability because it does not produce any by-products during its setting reaction that could evaporate and cause shrinkage. This stability allows the impression to be poured up to a week later without significant distortion.

Question 117: A patient refuses a recommended dental treatment. What is the appropriate action according to professional ethics and the law?

Proceed with the treatment because the dentist knows best
Contact the patient's family to override the decision
Document the refusal in the patient record (informed refusal), provide alternative options, and respect the patient's autonomous decision (Correct answer)
Discharge the patient from the practice immediately

Correct answer: Document the refusal in the patient record (informed refusal), provide alternative options, and respect the patient's autonomous decision

Patient autonomy is a fundamental ethical and legal right. When a patient refuses treatment, the provider must document the informed refusal, ensure the patient understands the consequences, offer alternatives, and respect the decision.

Question 118: During a dental appointment, a patient reports sudden chest pain and shortness of breath. What should the RDA do immediately?

Continue the procedure to minimize patient anxiety
Stop the procedure, summon the dentist, and call 911 if directed (Correct answer)
Have the patient breathe into a paper bag
Administer the office's epinephrine kit

Correct answer: Stop the procedure, summon the dentist, and call 911 if directed

Chest pain and dyspnea are signs of a potential cardiac emergency; stopping treatment and activating emergency services per office protocol is the correct response.

Question 119: What is the purpose of an alcohol-based hand rub (ABHR) in dental infection control?

It removes visible soil and blood from hands effectively
It replaces surgical hand scrubbing before invasive procedures
It sterilizes the skin surface
It rapidly reduces microbial counts on hands when they are not visibly soiled (Correct answer)

Correct answer: It rapidly reduces microbial counts on hands when they are not visibly soiled

ABHR rapidly reduces transient microorganisms on hands that are not visibly soiled; when hands are visibly soiled, soap and water must be used instead.

Question 120: A dental assistant completed an accredited program but has not yet passed the DANB exam. Which title may they legally use?

Dental Assistant (Correct answer)
Registered Dental Assistant
Licensed Dental Technician
Certified Dental Assistant

Correct answer: Dental Assistant

Until the credentialing exam is passed and the credential is granted, the individual may only use the undesignated title 'Dental Assistant.'

Question 121: What is the standard full-mouth series (FMX) for an adult patient?

Panoramic radiograph only
6 anterior and 8 posterior periapicals with 4 bitewings
14 periapical and 4 bitewing radiographs (18 images total) (Correct answer)
4 bitewing radiographs only

Correct answer: 14 periapical and 4 bitewing radiographs (18 images total)

A standard adult full-mouth series (FMX) typically consists of 14 periapical radiographs (showing all root structures) and 4 bitewing radiographs (showing interproximal bone and contacts), totaling 18 images.

Question 122: Under the legal doctrine of 'respondeat superior', who is held liable for the actions of a dental assistant performing their duties?

The patient
The employing dentist (Correct answer)
The dental assistant alone
The state dental board

Correct answer: The employing dentist

'Respondeat superior' is a Latin term meaning 'let the master answer.' This legal doctrine holds the employer (the dentist) responsible for the negligent acts of their employees (the dental assistant), provided those acts were committed within the scope of their employment.

Question 123: What is the difference between a base and a liner in restorative dentistry?

A liner is a thin coating for pulp protection; a base is a thick layer providing pulp protection AND structural support beneath a restoration (Correct answer)
Bases and liners serve the same purpose with no practical difference
A base is applied directly to the pulp; a liner replaces missing dentin
Liners are used only for amalgam; bases only for composite

Correct answer: A liner is a thin coating for pulp protection; a base is a thick layer providing pulp protection AND structural support beneath a restoration

A liner is a thin (0.5 mm) coating applied to the deepest portions of the preparation for pulp protection (chemical/biological). A base is a thicker (1–2 mm) material providing both thermal insulation and structural support, replacing missing dentin.

Question 124: What is the recommended maximum dose of epinephrine in local anesthetic for a patient with cardiovascular disease?

0.2 mg
0.4 mg
1.0 mg
0.04 mg (Correct answer)

Correct answer: 0.04 mg

For patients with significant cardiovascular disease, the maximum dose of epinephrine is 0.04 mg (two cartridges of 1:100,000 epinephrine) per appointment.

Question 125: Which federal agency develops the bloodborne pathogen standard that dental offices must follow?

Occupational Safety and Health Administration (OSHA) (Correct answer)
Food and Drug Administration (FDA)
Centers for Disease Control and Prevention (CDC)
Environmental Protection Agency (EPA)

Correct answer: Occupational Safety and Health Administration (OSHA)

OSHA's Bloodborne Pathogens Standard (29 CFR 1910.1030) is the enforceable federal regulation that dental employers must comply with to protect workers from exposure to blood-borne pathogens.

Question 126: Which error causes radiographic images to appear lighter (less dense) than normal?

Double exposure
Overexposure
Overdevelopment
Underexposure (Correct answer)

Correct answer: Underexposure

Underexposure (too little radiation reaching the film/sensor) produces a light, low-density image that appears washed out and lacks proper contrast for diagnostic use.

Question 127: Which disinfection level is required for semicritical instruments that are heat-sensitive?

Sterilization is never required for semicritical items
Low-level disinfection
Intermediate-level disinfection
High-level disinfection (Correct answer)

Correct answer: High-level disinfection

Heat-sensitive semicritical instruments that cannot be sterilized must undergo high-level disinfection (HLD), which kills all microorganisms except large numbers of bacterial spores.

Question 128: Which permanent tooth has a distinctive Carabelli's cusp?

Mandibular first molar
Mandibular second premolar
Maxillary first molar (Correct answer)
Maxillary first premolar

Correct answer: Maxillary first molar

Carabelli's cusp (or cusp of Carabelli) is a fifth cusp sometimes found on the mesiolingual surface of the maxillary first molar. It is a morphological variation.

Question 129: In California, which agency is responsible for licensing and regulating dental professionals?

California Dental Board (Dental Board of California) (Correct answer)
California Department of Health Services
California Department of Consumer Affairs directly
California Medical Board

Correct answer: California Dental Board (Dental Board of California)

The Dental Board of California (DBC), under the Department of Consumer Affairs, is the state regulatory agency responsible for licensing and regulating dentists, RDAs, RDEFs, and RDHs in California.

Question 130: Under HIPAA, what is the 'minimum necessary' standard as it applies to dental records?

The standard applies only when sharing records with insurance companies
Patient information disclosed or used should be limited to the minimum amount necessary to accomplish the intended purpose (Correct answer)
All staff may access all patient records for any purpose
Minimum necessary only applies to electronic records

Correct answer: Patient information disclosed or used should be limited to the minimum amount necessary to accomplish the intended purpose

The HIPAA minimum necessary standard requires that covered entities disclose, request, or use only the minimum PHI (Protected Health Information) needed to accomplish the specific purpose of the disclosure.

Question 131: Which of the following best describes the ethical principle of 'veracity' as it applies to dental assistants?

Avoiding any action that could harm the patient
Being truthful and honest with patients and colleagues (Correct answer)
Respecting the patient's right to make their own decisions
Treating all patients equally regardless of background

Correct answer: Being truthful and honest with patients and colleagues

Veracity is the ethical obligation to be truthful and accurate in all professional communications with patients and team members.

Question 132: The instrument with a small, spoon-shaped working end used to remove soft carious dentin is the:

Wedelstaedt chisel
Periodontal probe
Enamel hatchet
Spoon excavator (Correct answer)

Correct answer: Spoon excavator

The spoon excavator is designed specifically for the removal of soft, decayed dentin from the cavity preparation. Its sharp, spoon-like edges allow the dentist to gently scoop out the caries without removing healthy tooth structure.

Question 133: What is the recommended action if a polyvinyl siloxane (PVS) impression is contaminated with saliva before setting?

Apply bonding agent to the impression before pouring
Dry with air syringe and continue without issue
Discard the impression and retake it — saliva contamination ruins PVS accuracy (Correct answer)
Rinse with water and proceed with cementation

Correct answer: Discard the impression and retake it — saliva contamination ruins PVS accuracy

PVS impression materials are hydrophobic. Saliva or moisture contamination before or during setting compromises surface detail reproduction and dimensional accuracy, requiring the impression to be discarded and retaken.

Question 134: Which ethical principle requires a dental assistant to act in the best interest of the patient, even when it conflicts with the patient's own wishes?

Justice
Autonomy
Beneficence (Correct answer)
Nonmaleficence

Correct answer: Beneficence

Beneficence is the ethical duty to act in the patient's best interest and promote their well-being.

Question 135: What type of radiograph is used to examine the floor of the mouth, calculi in salivary glands, or impacted teeth?

Cephalometric radiograph
Occlusal radiograph (Correct answer)
Bitewing radiograph
Periapical radiograph

Correct answer: Occlusal radiograph

Occlusal radiographs use a larger film/sensor placed on the occlusal plane to image larger areas such as the floor of the mouth, palate, salivary stones, and impacted teeth.

Question 136: Which situation would most likely result in an RDA's credential being placed on probation?

Graduating from a non-CODA program
Failing to report a change of address
Completing CE in an unapproved topic
Practicing outside the scope defined by the supervising dentist (Correct answer)

Correct answer: Practicing outside the scope defined by the supervising dentist

Performing duties beyond the legal or dentist-defined scope of practice is a serious violation that can lead to disciplinary action, including probation.

Question 137: A rectangular collimator is preferred over a round (cylindrical) cone in dental radiography because it:

Eliminates the need for a lead apron during the exposure
Increases the sharpness of the image by reducing scatter
Allows more radiation to reach the receptor for a shorter exposure time
Significantly reduces the area of the patient's face exposed to the primary beam (Correct answer)

Correct answer: Significantly reduces the area of the patient's face exposed to the primary beam

Rectangular collimation restricts the x-ray beam to a shape closely matching the size of the receptor (film or sensor), dramatically reducing the volume of tissue irradiated and the patient's absorbed dose. Studies show rectangular collimation reduces patient exposure by up to 60% compared to round (open-ended) cylinders.

Question 138: The parotid, submandibular, and sublingual glands are collectively called:

Mucous glands
Major salivary glands (Correct answer)
Minor salivary glands
Serous glands

Correct answer: Major salivary glands

The parotid, submandibular, and sublingual glands are the three pairs of major salivary glands. They produce the bulk of saliva. Minor salivary glands are the hundreds of small glands scattered throughout the oral mucosa.

Question 139: Which sign differentiates a mild (vasovagal) syncope from a more serious cardiac event?

Both events respond equally to Trendelenburg position
Color of skin is the only reliable indicator
Unconsciousness in both events makes differentiation impossible
Presence of chest pain and irregular pulse vs. absence of these in syncope (Correct answer)

Correct answer: Presence of chest pain and irregular pulse vs. absence of these in syncope

Vasovagal syncope typically resolves quickly with Trendelenburg positioning and has no chest pain or arrhythmia, whereas cardiac events involve chest pain, irregular pulse, persistent unconsciousness, or failure to recover with simple positioning.

Question 140: Which dietary carbohydrate is considered the most cariogenic (decay-causing) because oral bacteria ferment it most readily?

Complex starches (e.g., bread, crackers)
Fructose from whole fruits
Sorbitol (sugar alcohol found in some gums)
Sucrose (table sugar) (Correct answer)

Correct answer: Sucrose (table sugar)

Sucrose is the most cariogenic carbohydrate. Streptococcus mutans uses sucrose to produce both lactic acid (which demineralizes enamel) and the glucan matrix that helps biofilm adhere to teeth. Sugar alcohols like sorbitol are not fermented by cariogenic bacteria and are considered non-cariogenic.

Question 141: A patient asks you for their dental records. Under California law, what is the correct response?

Only the dentist can release records — redirect all requests to the dentist without further action
Dental records cannot be released to patients, only to other dentists
Patients have the right to copies of their dental records; the office must provide copies within a reasonable time upon written request, and may charge a reasonable copying fee (Correct answer)
Records can be withheld if the patient has an outstanding balance

Correct answer: Patients have the right to copies of their dental records; the office must provide copies within a reasonable time upon written request, and may charge a reasonable copying fee

Under California Health and Safety Code §123111, patients have the right to inspect and receive copies of their dental records. The office must provide records within 15 days of a written request and may charge a reasonable copying fee.

Question 142: A primary advantage of using glass ionomer cement as a restorative material is its ability to:

Release fluoride (Correct answer)
Achieve a very high polish
Withstand high occlusal forces in posterior teeth
Be used without a bonding agent

Correct answer: Release fluoride

Glass ionomer cements contain fluoride within their glass particle composition. After placement, they slowly release this fluoride into the surrounding tooth structure, which helps to inhibit recurrent decay and can aid in remineralization.

Question 143: Which of the following best describes the typical work schedule of an RDA?

On-call 24/7
Strictly 9 to 5, Monday through Friday
Flexible, often including evenings or weekends (Correct answer)
Seasonal work with long breaks in between

Correct answer: Flexible, often including evenings or weekends

The typical work schedule of an RDA is often flexible, frequently including evenings or weekends to accommodate patients' varied availability. Unlike a strict 9-to-5 schedule, dental offices often extend hours to meet patient demand. This flexibility allows dental practices to serve a broader community and can offer RDAs diverse scheduling options.

Question 144: Which task related to patient care might an RDA be responsible for?

Performing tooth extractions
Instructing patients on postoperative care (Correct answer)
Determining the need for orthodontic braces
Administering sedative drugs

Correct answer: Instructing patients on postoperative care

An RDA is often responsible for instructing patients on postoperative care, which is a vital aspect of patient education. This includes explaining medication schedules, dietary restrictions, oral hygiene practices, and signs of complications after a procedure. Clear and empathetic communication helps ensure proper healing and patient compliance.

Question 145: A dental assistant notices that the protective eyewear worn by a patient has visible blood on it after a procedure. The correct action is to:

Rinse under tap water only
Clean and disinfect with an intermediate-level disinfectant before reuse on the next patient (Correct answer)
Wipe the eyewear with a dry paper towel and return it to the dispenser
Discard the eyewear immediately

Correct answer: Clean and disinfect with an intermediate-level disinfectant before reuse on the next patient

Reusable patient eyewear must be cleaned to remove organic debris and then disinfected with an intermediate-level disinfectant before being used on the next patient.

Question 146: According to the Spaulding Classification system, which of the following is considered a semi-critical instrument?

Surgical scalpel
Blood pressure cuff
Amalgam condenser (Correct answer)
Dental forceps

Correct answer: Amalgam condenser

Semi-critical instruments are those that contact mucous membranes or non-intact skin but do not penetrate soft tissue. An amalgam condenser fits this description, as it is used in the mouth but does not cut tissue. These instruments require, at a minimum, high-level disinfection, but sterilization is preferred.

Question 147: Which composite resin curing light wavelength range is needed to activate camphorquinone, the most common photoinitiator?

350–380 nm (ultraviolet)
400–500 nm (blue light) (Correct answer)
550–600 nm (green light)
650–700 nm (red light)

Correct answer: 400–500 nm (blue light)

Camphorquinone is activated by blue light in the 400–500 nm range, with peak absorption at approximately 468 nm.

Question 148: Which document legally authorizes a dental assistant to perform expanded functions in states that permit them?

Written delegation from the supervising dentist (Correct answer)
OSHA compliance certificate
ADA membership card
Dental Practice Act amendments

Correct answer: Written delegation from the supervising dentist

Written delegation from the supervising dentist is the legal authorization required for a dental assistant to perform expanded functions.

Question 149: Which anatomical landmark is used to guide the inferior alveolar nerve block (IANB) injection?

The maxillary tuberosity
The mental foramen
The incisive foramen
The coronoid notch and pterygomandibular raphe (Correct answer)

Correct answer: The coronoid notch and pterygomandibular raphe

The IANB uses the coronoid notch and pterygomandibular raphe as external landmarks to direct the needle toward the mandibular foramen.

Question 150: If a patient experiences a grand mal seizure in the dental chair, the primary responsibility of the dental team is to:

Firmly restrain the patient's arms and legs
Prevent the patient from injury and clear the area (Correct answer)
Insert a padded tongue blade into the patient's mouth
Immediately administer oxygen

Correct answer: Prevent the patient from injury and clear the area

During a convulsive seizure, the main priority is to prevent the patient from injuring themselves. This involves clearing the area of any sharp or hard objects and gently protecting their head, without actively restraining their movements.

California RDA Written Exam

The California Registered Dental Assistant exam certifies competency in dental procedures, infection control, radiography, patient care, and state dental practice law and ethics.

150

Questions

180 min

Time Limit

75%

To Pass

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These practice questions were written with AI tools. They are not real exam questions. Exam facts are checked against the official sources listed below. Not reviewed by a subject-matter expert. Editorial policy

Sources & references

Exam facts on this page (fees, format, dates, passing scores) are checked against these official sources; the date is our last check. Editorial policy

dbc.ca.gov — Eligibility, fees, registration deadline, exam information · verified Oct 2026
americanmedtech.org — Eligibility, test delivery, registration deadline, retake policy, score release · verified Oct 2026
test-takers.psiexams.com — Fees, retake policy, score release, time limit · verified Oct 2026