Expanded Function Dental Auxiliary (EFDA) Certification Exam — Questions and Answers

Question 1: What is the recommended action if an alginate impression cannot be poured immediately?

Store in an airtight bag with a moist paper towel for up to 1 hour (Correct answer)
Freeze the impression to halt dimensional change
Spray with disinfectant and leave uncovered on the counter
Submerge fully in water for up to 24 hours

Correct answer: Store in an airtight bag with a moist paper towel for up to 1 hour

Alginate should be wrapped in a damp towel and sealed in a bag to prevent syneresis and imbibition; ideally poured within 1 hour.

Question 2: During medical history review, a patient reports taking warfarin. What is the primary concern for dental treatment?

Elevated blood pressure
Drug-induced xerostomia
Increased infection risk
Prolonged bleeding time (Correct answer)

Correct answer: Prolonged bleeding time

Warfarin is an anticoagulant that prolongs bleeding time, requiring coordination with the patient's physician before invasive procedures.

Question 3: What isolation method is considered the GOLD STANDARD for sealant application?

Gauze squares placed in the vestibule
Dry angles and saliva ejector
Cotton rolls alone
Rubber dam (Correct answer)

Correct answer: Rubber dam

Rubber dam provides the most reliable moisture control and is considered the gold standard for sealant placement, though cotton roll isolation is commonly used in practice.

Question 4: Which type of dental material is indicated for a Class V restoration in a high-caries-risk patient due to its fluoride-releasing properties?

Amalgam
Resin-modified glass ionomer (Correct answer)
Porcelain
Composite resin

Correct answer: Resin-modified glass ionomer

Resin-modified glass ionomer releases fluoride over time, providing cariostatic benefits ideal for high-risk patients.

Question 5: What is a common side effect of opioid analgesics prescribed after oral surgery?

Tachycardia
Constipation (Correct answer)
Hypertension
Increased salivation

Correct answer: Constipation

Opioids slow gastrointestinal motility, commonly causing constipation as a predictable side effect.

Question 6: When isolating a single quadrant for a Class II posterior restoration, how many teeth are typically included in the rubber dam isolation?

Three to five teeth including the operative tooth and surrounding teeth (Correct answer)
Only the one tooth being restored
The entire arch is always isolated
Two adjacent teeth only

Correct answer: Three to five teeth including the operative tooth and surrounding teeth

Isolating three to five teeth provides adequate access, visibility, and working space while maintaining a dry field for the proximal restoration.

Question 7: When seating a patient in the dental chair, which position is most appropriate for routine restorative procedures?

Supine with feet slightly elevated (Correct answer)
Upright at 90 degrees
Semi-supine at approximately 45 degrees
Trendelenburg position

Correct answer: Supine with feet slightly elevated

The supine position with feet slightly elevated is standard for most restorative procedures, providing optimal access and patient comfort.

Question 8: Why is it important to monitor radiographic equipment regularly?

To ensure the equipment is safe, accurate, and properly maintained (Correct answer)
To minimize patient interaction with the dentist
To increase the cost of the procedure
To decrease the number of patients treated

Correct answer: To ensure the equipment is safe, accurate, and properly maintained

Regular monitoring and maintenance of radiographic equipment are crucial for several reasons. It ensures the equipment operates safely, preventing potential hazards to both patients and staff, and guarantees the accuracy of diagnostic images. Consistent checks also help identify and address issues early, prolonging the equipment's lifespan and ensuring reliable performance for optimal patient care.

Question 9: Which disinfectant classification is required for clinical contact surfaces in the dental operatory between patients?

Sterilant
Intermediate-level disinfectant (Correct answer)
High-level disinfectant
Low-level disinfectant

Correct answer: Intermediate-level disinfectant

Intermediate-level disinfectants are required for clinical contact surfaces because they kill mycobacteria, most viruses, and vegetative bacteria.

Question 10: A liner differs from a base primarily in that a liner:

Is applied in a thick layer to provide thermal insulation
Must always be light-cured before placing the restoration
Is a thin layer applied mainly for biological protection rather than mechanical support (Correct answer)
Contains higher concentrations of zinc to strengthen dentin

Correct answer: Is a thin layer applied mainly for biological protection rather than mechanical support

Liners are applied in thin layers (under 0.5 mm) to provide biological and chemical protection without the bulk or compressive strength of a base.

Question 11: In an ideal Class I occlusion, the mesiobuccal cusp of the maxillary first molar occludes in the:

Central fossa of the mandibular first molar
Buccal groove of the mandibular first molar (Correct answer)
Distal fossa of the mandibular second premolar
Mesial pit of the mandibular first molar

Correct answer: Buccal groove of the mandibular first molar

Angle's Class I key is that the mesiobuccal cusp of the maxillary first molar occludes in the buccal groove of the mandibular first molar.

Question 12: In a normal occlusal relationship (Class I), which cusps are considered the non-functional or non-supporting cusps?

Lingual cusps of both maxillary and mandibular posterior teeth.
Buccal cusps of maxillary posterior teeth and lingual cusps of mandibular posterior teeth. (Correct answer)
Buccal cusps of both maxillary and mandibular posterior teeth.
Lingual cusps of maxillary posterior teeth and buccal cusps of mandibular posterior teeth.

Correct answer: Buccal cusps of maxillary posterior teeth and lingual cusps of mandibular posterior teeth.

In a normal Class I occlusion, the functional (or supporting) cusps are the lingual cusps of the maxillary teeth and the buccal cusps of the mandibular teeth, as these occlude in the central fossae of the opposing teeth. Therefore, the non-functional (or shearing) cusps are the buccal cusps of the maxillary posterior teeth and the lingual cusps of the mandibular posterior teeth. [36]

Question 13: Which material is most commonly used as a cavity liner under composite resin restorations to promote pulpal healing?

Glass ionomer base
Zinc phosphate cement
Zinc oxide eugenol
Calcium hydroxide (Correct answer)

Correct answer: Calcium hydroxide

Calcium hydroxide is the preferred liner under composites because it stimulates secondary dentin formation and has excellent biocompatibility.

Question 14: Curve of Spee refers to the:

Vertical overlap of anterior teeth
Anteroposterior curvature of the occlusal plane from canine to last molar (Correct answer)
Curve of the mandibular arch in centric relation
Lateral curve of the dental arch when viewed from above

Correct answer: Anteroposterior curvature of the occlusal plane from canine to last molar

The curve of Spee is the anteroposterior (sagittal) curvature of the mandibular occlusal plane, curving upward from the canine back through the molars.

Question 15: When processing conventional dental radiographs, a film that appears too dark (overexposed) may result from:

Developer temperature too low
Fixer solution too concentrated
Insufficient rinsing between developer and fixer
Developer solution too concentrated or development time too long (Correct answer)

Correct answer: Developer solution too concentrated or development time too long

Overdevelopment due to high developer temperature, excessive concentration, or prolonged development time causes excessive silver halide reduction, producing a dark film.

Question 16: A tooth with a proximal carious lesion is being restored. Which cavity preparation classification describes this lesion on a posterior tooth?

Class II (Correct answer)
Class III
Class I
Class V

Correct answer: Class II

Class II cavity preparations involve the proximal surfaces (mesial or distal) of posterior teeth (premolars and molars).

Question 17: When evaluating sealant integrity at a recall appointment, which instrument is most appropriate?

Periodontal probe
Articulating paper
Explorer (Correct answer)
Mouth mirror only

Correct answer: Explorer

A sharp explorer is used to assess sealant retention by checking for voids, gaps, or areas where the sealant can be displaced.

Question 18: A heavy-body PVS material placed in the impression tray is also called:

Light body
Putty or tray material (Correct answer)
Monophase material
Wash material

Correct answer: Putty or tray material

Heavy-body or putty PVS fills the tray and provides bulk support while light-body (wash) material captures fine detail.

Question 19: When applying a resin sealant, moisture contamination before light curing will most likely cause:

Sealant discoloration
Poor adhesion and early sealant loss (Correct answer)
Faster polymerization
Increased fluoride release

Correct answer: Poor adhesion and early sealant loss

Moisture contamination disrupts the bond between the etched enamel and the resin sealant, leading to microleakage and early failure.

Question 20: When is biological monitoring (spore testing) of an autoclave required at minimum?

Daily
Weekly (Correct answer)
After each load
Monthly

Correct answer: Weekly

The CDC and OSAP recommend weekly spore testing of sterilizers to verify that sterilization conditions are being achieved.

Question 21: Which of the following statements best describes the primary difference between a dental liner and a dental base?

Liners are used for thermal insulation, while bases are used to stimulate reparative dentin.
Liners release high levels of fluoride, while bases are primarily sedative in nature.
Liners are only used under amalgam restorations, while bases are only used under composite restorations.
Liners are placed in a thin layer for pulpal protection, while bases are placed in a thicker layer for mechanical support. (Correct answer)

Correct answer: Liners are placed in a thin layer for pulpal protection, while bases are placed in a thicker layer for mechanical support.

The main distinction lies in their thickness and primary function. Liners are thin coatings (typically <0.5mm) designed to seal dentinal tubules and protect the pulp chemically or therapeutically. Bases are thicker layers that provide thermal insulation and, importantly, distribute occlusal forces, acting as a supportive foundation for the final restoration.

Question 22: A dentist requires a highly accurate and dimensionally stable final impression for a three-unit bridge. The material must have excellent tear strength and allow for multiple pours of the model if needed. Which material best fits this description?

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

Correct answer: Polyvinyl siloxane (PVS)

Polyvinyl siloxane (PVS), also known as addition silicone, is known for its superior dimensional stability, high accuracy, and excellent tear strength. Its stability allows impressions to be poured long after they are taken and enables multiple accurate casts to be made from a single impression.

Question 23: Which dental drug interaction requires the EFDA to alert the dentist before administering a local anesthetic with epinephrine?

Patient takes non-selective beta-blockers (Correct answer)
Patient takes antacids
Patient takes vitamin C supplements
Patient takes aspirin daily

Correct answer: Patient takes non-selective beta-blockers

Non-selective beta-blockers can potentiate the vasopressor effect of epinephrine, causing a significant hypertensive episode.

Question 24: A pit and fissure sealant is indicated when the fissure morphology is:

Deep and narrow, retaining plaque and debris (Correct answer)
Shallow and self-cleansing
Already showing early carious lesions visible on radiograph
Broad and easy to access with a toothbrush

Correct answer: Deep and narrow, retaining plaque and debris

Deep, narrow pits and fissures that cannot be cleaned by toothbrushing are the primary indication for sealant placement.

Question 25: When placing zinc phosphate cement as a base, why must mixing be done on a cool glass slab?

To speed up the setting reaction
To prevent moisture contamination
To slow the exothermic reaction and extend working time (Correct answer)
To increase the powder-to-liquid ratio

Correct answer: To slow the exothermic reaction and extend working time

A cool slab dissipates the heat generated during mixing, slowing the exothermic reaction and extending working time.

Question 26: Which liner is appropriate for use directly under composite resin without inhibiting polymerization?

Traditional zinc oxide eugenol base
Light-cured calcium hydroxide or resin-modified glass ionomer (Correct answer)
Zinc oxide eugenol (ZOE)
Copal varnish

Correct answer: Light-cured calcium hydroxide or resin-modified glass ionomer

Light-cured calcium hydroxide and resin-modified glass ionomer liners are compatible with composite resin and will not inhibit its polymerization.

Question 27: The term 'ergonomics' in four-handed dentistry primarily refers to:

The speed at which instruments are transferred between operator and assistant
Sterilization techniques used between patients
The number of instruments laid out on the tray setup
Positioning of personnel and equipment to reduce physical strain and improve efficiency (Correct answer)

Correct answer: Positioning of personnel and equipment to reduce physical strain and improve efficiency

Ergonomics addresses body positioning, equipment placement, and workflow design to prevent musculoskeletal injury and maximize efficiency.

Question 28: Which of the following is an example of a critical dental instrument requiring sterilization?

Radiograph viewbox
X-ray head position indicator device (PID)
Dental light handle
Amalgam condenser (Correct answer)

Correct answer: Amalgam condenser

Amalgam condensers are critical instruments that penetrate soft tissue or bone and must be sterilized between patient uses.

Question 29: A patient's thyroid collar is omitted during bitewing radiographs. What is the primary concern?

Unnecessary radiation to the thyroid gland (Correct answer)
Patient discomfort
Image distortion
Sensor positioning difficulty

Correct answer: Unnecessary radiation to the thyroid gland

The thyroid gland is radiosensitive, and omitting the thyroid collar unnecessarily exposes it to ionizing radiation during dental radiography.

Question 30: Which of the following best defines centric occlusion?

The most retruded position of the condyles in the glenoid fossa.
A jaw position determined solely by ligament and muscle guidance.
The end-to-end contact of the anterior teeth.
The maximum intercuspation of the maxillary and mandibular teeth. (Correct answer)

Correct answer: The maximum intercuspation of the maxillary and mandibular teeth.

Centric occlusion, also known as maximum intercuspation (MIP), is defined by the way the teeth fit together with the most contact, regardless of the condylar position. It is a tooth-determined position. [10, 14, 16, 19]

Question 31: During the placement of a Class III composite on an anterior tooth, the EFDA notices that maintaining a dry field is extremely difficult due to gingival bleeding. What is the most likely consequence if moisture contaminates the preparation?

The composite material will not polymerize when light-cured.
The procedure will be more comfortable for the patient.
A significant decrease in bond strength, potentially leading to restoration failure. (Correct answer)
The final restoration will have a darker shade than intended.

Correct answer: A significant decrease in bond strength, potentially leading to restoration failure.

Proper isolation and moisture control are critical for the success of composite restorations. Contamination of the etched enamel and dentin surfaces by saliva, blood, or moisture will interfere with the adhesive bonding process, resulting in a weak bond. This can lead to microleakage, postoperative sensitivity, and premature failure of the restoration.

Question 32: Which of the following materials is applied in a thin layer to seal dentinal tubules and is contraindicated for use with composite resin restorations because it interferes with adhesion?

Cavity Varnish (Correct answer)
Glass Ionomer
Calcium Hydroxide
Zinc Phosphate Cement

Correct answer: Cavity Varnish

Cavity varnish, such as Copalite, is a liquid resin used to seal dentinal tubules to reduce microleakage. However, it is not compatible with resin composite materials because it inhibits the polymerization and bonding of the resin to the tooth structure.

Question 33: An EFDA is assisting with a final impression using a polyether material. Which of the following is a key characteristic of this material that must be considered when handling the final impression?

It has a very long setting time, often exceeding 15 minutes.
It must be poured within 5 minutes due to poor dimensional stability.
It is highly hydrophobic and repels all moisture.
It is very rigid when set and can be difficult to remove from the mouth, especially around undercuts. (Correct answer)

Correct answer: It is very rigid when set and can be difficult to remove from the mouth, especially around undercuts.

Polyether impression materials are known for their rigidity and stiffness once set. While this property contributes to their accuracy, it can make tray removal challenging, especially in patients with significant undercuts, long teeth, or periodontal involvement. Care must be taken during removal to avoid torquing the tray or causing patient discomfort.

Question 34: Why should dental offices have a designated infection control protocol for radiography?

To make it easier for patients to access the office
To reduce the cost of radiography
To make the procedure more time-consuming
To ensure the safety and health of patients and staff during radiographic procedures (Correct answer)

Correct answer: To ensure the safety and health of patients and staff during radiographic procedures

A specific infection control protocol for radiography is essential to standardize practices and minimize risks associated with imaging procedures. It provides clear guidelines for handling equipment, using barriers, and disinfecting surfaces, ensuring consistent adherence to safety standards. This systematic approach effectively protects both patients from potential infections and staff from occupational exposure to pathogens.

Question 35: What is the purpose of the 'problem list' in a comprehensive treatment plan?

To document the patient's payment method
To list all dental materials that will be used
To summarize all identified dental and medical issues requiring attention (Correct answer)
To record the referring dentist's information

Correct answer: To summarize all identified dental and medical issues requiring attention

The problem list consolidates all identified clinical findings, both dental and systemic, that must be addressed in the treatment plan.

Question 36: What is the role of radiographic shielding in patient safety?

To protect patients from unnecessary radiation exposure (Correct answer)
To reduce the number of X-rays needed
To make the procedure faster
To focus on the aesthetic quality of the images

Correct answer: To protect patients from unnecessary radiation exposure

Radiographic shielding, such as lead aprons and thyroid collars, is a critical component of patient safety during dental X-rays. Its primary role is to block or reduce the amount of scatter radiation reaching sensitive organs outside the immediate area of interest. This minimizes the patient's overall radiation dose, aligning with the principle of keeping exposure "As Low As Reasonably Achievable" (ALARA).

Question 37: What is the primary advantage of digital radiography over conventional film radiography?

Reduced radiation exposure of up to 80% (Correct answer)
No need for infection control protocols
Images cannot be overexposed
Higher resolution images

Correct answer: Reduced radiation exposure of up to 80%

Digital radiography can reduce radiation exposure by up to 80% compared to conventional film because digital sensors are much more sensitive to X-rays.

Question 38: Which type of impression tray is custom-made from the patient's diagnostic model?

Individual custom tray (Correct answer)
Quadrant bite tray
Stock metal tray
Perforated plastic tray

Correct answer: Individual custom tray

Custom trays are fabricated directly over a patient's cast, providing a uniform spacer distance from tissues and improving final impression accuracy.

Question 39: In the paralleling technique, the film/sensor must be positioned:

Against the lingual surface of the teeth
At a 45-degree angle to the tooth
Perpendicular to the occlusal plane
Parallel to the long axis of the tooth (Correct answer)

Correct answer: Parallel to the long axis of the tooth

In the paralleling technique, the film or sensor is placed parallel to the long axis of the tooth to produce a geometrically accurate, undistorted image.

Question 40: Which base material is contraindicated under composite resin due to its eugenol content interfering with polymerization?

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

Correct answer: Zinc oxide eugenol (ZOE)

Eugenol in ZOE inhibits the polymerization of composite resin, preventing adequate setting of the restoration.

Question 41: What is the PRIMARY reason for maintaining proper occlusal anatomy on a provisional crown?

To improve the esthetics of the posterior region
To prevent over-eruption of opposing teeth and maintain occlusal vertical dimension (Correct answer)
To make the provisional easier to remove
To reduce the amount of cement needed

Correct answer: To prevent over-eruption of opposing teeth and maintain occlusal vertical dimension

Proper occlusal anatomy maintains the vertical dimension and prevents supraeruption of opposing teeth, which would compromise space for the final restoration.

Question 42: Which salivary gland produces the most serous (watery) saliva and has its duct (Stensen's duct) opening near the maxillary second molar?

Minor salivary glands
Submandibular gland
Parotid gland (Correct answer)
Sublingual gland

Correct answer: Parotid gland

The parotid gland is the largest salivary gland and produces primarily serous saliva, draining via Stensen's duct opposite the maxillary second molar.

Question 43: The Frankfort plane is used as a horizontal reference and passes through which landmarks?

Menton and gonion
ANS and PNS
Nasion, sella, and articulare
Porion and orbitale (Correct answer)

Correct answer: Porion and orbitale

The Frankfort horizontal plane passes through the porion (top of external auditory meatus) and orbitale (lowest point of the orbital rim).

Question 44: Which of the following is a sign of inadequate curing of a PMMA provisional crown?

Excessive shrinkage at the margins
Bright white opaque color
Tacky or soft surface and persistent monomer odor (Correct answer)
Excessive hardness and brittleness

Correct answer: Tacky or soft surface and persistent monomer odor

A tacky or soft surface with persistent monomer smell indicates incomplete polymerization, meaning the material has not fully cured.

Question 45: What is a key reason why dental impression materials should be poured promptly after removal from the mouth?

The material becomes too rigid for pouring
Syneresis or imbibition can alter the dimensional accuracy of the impression (Correct answer)
Color changes make it difficult to identify defects
Setting reaction of the stone is inhibited by contact with impression material

Correct answer: Syneresis or imbibition can alter the dimensional accuracy of the impression

Alginate and hydrocolloid impressions undergo syneresis (shrinkage) or imbibition (expansion) if not poured immediately, causing dimensional inaccuracies in the resulting model.

Question 46: Which property of addition silicone makes it preferred for implant-level impressions?

High compressibility that captures thread detail
Excellent dimensional stability allowing delayed pours (Correct answer)
Rapid set time under 1 minute
Biocompatibility with titanium

Correct answer: Excellent dimensional stability allowing delayed pours

PVS impressions can be stored for days to weeks without significant dimensional change, making them ideal when models must be poured remotely or later.

Question 47: Which of the following clinical scenarios is MOST appropriate for sealant placement?

An adult with existing amalgam restorations on all posterior teeth
A 30-year-old with smooth, well-coalesced occlusal surfaces
A 7-year-old with newly erupted first molars showing deep fissures (Correct answer)
A 15-year-old with active interproximal decay in multiple teeth

Correct answer: A 7-year-old with newly erupted first molars showing deep fissures

Newly erupted molars in children with deep, caries-susceptible fissures represent the ideal candidate for preventive sealant application.

Question 48: Which permanent teeth succeed the primary molars?

Permanent molars
Permanent canines
Permanent premolars (Correct answer)
Permanent incisors

Correct answer: Permanent premolars

The 20 primary teeth are replaced by permanent successors. Specifically, the primary first and second molars are exfoliated and replaced by the permanent first and second premolars (bicuspids). The permanent molars erupt distal (behind) to the primary dentition and are not succedaneous. [15, 23, 24, 25, 27]

Question 49: Why is it important to calibrate dental equipment regularly?

To increase the speed of procedures
To ensure equipment operates accurately and delivers reliable results (Correct answer)
To limit patient interaction with the equipment
To reduce equipment usage

Correct answer: To ensure equipment operates accurately and delivers reliable results

Calibration is the process of adjusting dental equipment to ensure it performs within specified parameters and provides accurate measurements or outputs. Regular calibration is vital for diagnostic tools, such as X-ray machines, and treatment devices, like curing lights, to guarantee precise and effective patient care. This practice ensures consistent quality of treatment and patient safety.

Question 50: A patient reports jaw clicking and limited mouth opening. Which structure is most likely involved?

Temporomandibular joint (Correct answer)
Masseter muscle
Lateral pterygoid nerve
Parotid gland

Correct answer: Temporomandibular joint

Clicking sounds and limited opening are hallmark signs of temporomandibular joint (TMJ) dysfunction, often due to disc displacement.

Question 51: Which radiographic finding would indicate that a cavity preparation for amalgam is of adequate depth?

The preparation has reached into dentin but does not approach the pulp (Correct answer)
The preparation extends into the pulp chamber
The preparation shows a pulp exposure
The preparation is limited to enamel only

Correct answer: The preparation has reached into dentin but does not approach the pulp

Ideal amalgam preparations extend into dentin for mechanical retention without approaching or exposing the pulp.

Question 52: A sealant placed over an incipient (non-cavitated) carious lesion will most likely:

Result in pulpal exposure over time
Cause the enamel to remineralize immediately
Arrest caries progression by sealing bacteria from nutrients (Correct answer)
Accelerate the progression of decay beneath the sealant

Correct answer: Arrest caries progression by sealing bacteria from nutrients

Research supports that intact sealants over non-cavitated lesions arrest caries by cutting off bacterial access to fermentable carbohydrates.

Question 53: When using an amalgamator, which factor most directly affects the consistency and strength of the amalgam mix?

The brand of amalgam capsule used
The temperature of the operatory
The size of the capsule
The trituration time and speed (Correct answer)

Correct answer: The trituration time and speed

Trituration time and speed control the degree of amalgamation, directly affecting the working consistency and final strength of the restoration.

Question 54: When taking a preliminary alginate impression, the dentist notices voids in the palate area. What is the most likely cause?

Air entrapment during spatulation or tray seating (Correct answer)
Too much water used in the mix
The tray was seated too slowly
The alginate was over-spatulated

Correct answer: Air entrapment during spatulation or tray seating

Voids in the impression are commonly caused by air bubbles trapped during mixing or when the material fails to flow into all areas during tray placement.

Question 55: Elongation of a radiographic image is caused by:

Excessive horizontal angulation
Insufficient horizontal angulation
Excessive vertical angulation
Insufficient vertical angulation (Correct answer)

Correct answer: Insufficient vertical angulation

Elongation occurs when the vertical angulation is too flat (insufficient), causing the X-ray beam to strike the tooth and film at an angle that stretches the image.

Question 56: When mixing glass ionomer cement for luting, which ratio produces the correct consistency?

Higher liquid to increase flow
Manufacturer's specified powder-to-liquid ratio (Correct answer)
Equal parts powder and liquid
Higher powder to decrease solubility

Correct answer: Manufacturer's specified powder-to-liquid ratio

Glass ionomer cement must be mixed at the manufacturer's specified powder-to-liquid ratio to achieve the correct viscosity, strength, and fluoride release.

Question 57: What is the proper technique for handling contaminated radiographic film packets after exposure?

Wipe the outside of the packet with disinfectant before opening
Soak packets in cold sterilization solution
Place contaminated packets directly in the processor
Drop the film from the packet directly onto a clean surface (Correct answer)

Correct answer: Drop the film from the packet directly onto a clean surface

The 'drop technique' involves opening the contaminated packet with gloved hands and dropping the uncontaminated inner film onto a clean surface, preventing cross-contamination.

Question 58: What does the term 'attached gingiva' refer to?

Firm, keratinized tissue bound to the tooth and alveolar bone (Correct answer)
Gingiva lining the inner surface of the cheeks
Tissue covering the hard palate only
Loose tissue in the mucobuccal fold

Correct answer: Firm, keratinized tissue bound to the tooth and alveolar bone

Attached gingiva is the firm, stippled, keratinized tissue that is tightly bound to the underlying alveolar bone and cementum.

Question 59: When checking the occlusion after sealant placement, which material is used?

Articulating paper (Correct answer)
Prophy paste
Fluoride gel
Disclosing solution

Correct answer: Articulating paper

Articulating paper marks the areas of premature occlusal contact so the EFDA can identify and adjust high spots on the sealant.

Question 60: For a Class II MO composite restoration on tooth #29, which matrix system is generally preferred to achieve the most anatomically correct contact and contour?

Universal (Tofflemire) matrix
Pre-formed metal shell crown
Mylar strip and wedge
Sectional matrix with a separating ring (Correct answer)

Correct answer: Sectional matrix with a separating ring

Sectional matrix systems are designed to recreate the tight, convex contacts and natural contours of posterior teeth more effectively than a universal Tofflemire band, which tends to flatten the proximal surface. The separating ring provides the necessary tooth separation to ensure a firm contact after the matrix is removed.

Question 61: What information is captured in a dental treatment plan's 'sequencing' phase?

The informed consent documentation
The fee estimates for each procedure
The order in which procedures will be performed (Correct answer)
The patient's insurance coverage details

Correct answer: The order in which procedures will be performed

Sequencing determines the logical order of treatment, typically addressing emergencies first, then disease control, restorative phase, and finally maintenance.

Question 62: When mixing addition silicone (PVS) impression material, what should the clinician avoid?

Using latex gloves during mixing (Correct answer)
Using an automix cartridge
Mixing on a glass slab
Loading the tray within 30 seconds

Correct answer: Using latex gloves during mixing

Sulfur compounds in latex gloves can inhibit the polymerization of addition silicone, resulting in a tacky, unset surface.

Question 63: The Cusp of Carabelli is an accessory cusp most frequently found on which surface of which tooth?

Distobuccal of a maxillary second molar
Mesiolingual of a mandibular first molar
Mesiolingual of a maxillary first molar (Correct answer)
Distobuccal of a mandibular first molar

Correct answer: Mesiolingual of a maxillary first molar

The Cusp of Carabelli, also known as Carabelli's tubercle, is a non-functional fifth cusp located on the mesiolingual (palatal) surface of the maxillary first molar. It can also be found on primary maxillary second molars. [2, 4, 6, 8, 13, 33]

Question 64: Which dimension error occurs when an alginate impression is left in the mouth too long after setting?

Syneresis causing shrinkage (Correct answer)
Imbibition causing expansion
Polymerization continues causing contraction
No dimensional change occurs after setting

Correct answer: Syneresis causing shrinkage

Prolonged oral contact allows syneresis — expulsion of liquid from the gel — causing the alginate to shrink slightly.

Question 65: During the 'remove and reline' phase of direct provisional fabrication, when should the initial shell be removed from the mouth?

After 10 minutes of curing
After the material is completely hard
Immediately after injection of the material
During the rubbery or doughy stage, before final set (Correct answer)

Correct answer: During the rubbery or doughy stage, before final set

Removing the shell during the rubbery stage prevents locking into undercuts while preserving the shape needed for the final reline.

Question 66: The EFDA should inform the dentist if, during composite finishing, the restoration feels 'soft' or scratches easily because this indicates:

The shade is incorrect
The matrix was removed too early
The composite is over-cured
Incomplete polymerization requiring additional curing or replacement (Correct answer)

Correct answer: Incomplete polymerization requiring additional curing or replacement

A soft or easily scratched composite surface indicates inadequate polymerization, likely due to insufficient curing time, distance, or light intensity.

Question 67: When should the curing light tip be cleaned during a clinical day?

Only at the start of the day
Only at the end of the day
Once per week
Between each patient (Correct answer)

Correct answer: Between each patient

Curing light tips must be disinfected or sterilized between patients to prevent cross-contamination.

Question 68: The color shade of a provisional crown is MOST important for which type of restoration?

Maxillary third molar
Mandibular first premolar
Mandibular second molar
Maxillary central incisor (Correct answer)

Correct answer: Maxillary central incisor

Maxillary central incisors are highly visible, so shade matching of the provisional is critical to patient satisfaction and proper shade communication to the lab.

Question 69: What is the purpose of applying cavity varnish before placing zinc phosphate cement?

Seal dentinal tubules to reduce pulpal irritation from cement acidity (Correct answer)
Act as a desensitizer for post-operative sensitivity
Increase the strength of the final restoration
Improve bonding of cement to dentin

Correct answer: Seal dentinal tubules to reduce pulpal irritation from cement acidity

Cavity varnish seals dentinal tubules to protect the pulp from the low pH of freshly mixed zinc phosphate cement.

Question 70: The EFDA is assisting during a procedure when the patient begins coughing persistently. The most appropriate action is to:

Stop suctioning to avoid irritation
Ask the patient to swallow to clear the throat
Continue the procedure and ignore the cough
Pause the procedure and lower the patient's head (Correct answer)

Correct answer: Pause the procedure and lower the patient's head

Pausing and lowering the head helps prevent aspiration and allows the patient to clear their airway safely.

Question 71: What is the biological effect that dental X-rays are most concerned with in terms of long-term risk?

Acute radiation syndrome
Thermal burns to tissue
Stochastic effects such as carcinogenesis (Correct answer)
Deterministic effects on bone marrow

Correct answer: Stochastic effects such as carcinogenesis

Stochastic effects, including the potential induction of cancer, are the primary long-term concern with low-dose dental X-ray exposure, as their probability increases with cumulative dose.

Question 72: Which standard precaution requires treating all patient blood and body fluids as potentially infectious?

Universal precautions (Correct answer)
Airborne precautions
Contact precautions
Reverse isolation

Correct answer: Universal precautions

Universal precautions, expanded into Standard Precautions by the CDC, require treating all blood and body fluids from every patient as potentially infectious regardless of known disease status.

Question 73: An EFDA notices that the provisional crown has excess material (flash) extending onto the gingival tissue. The BEST instrument to remove this excess is:

High-speed handpiece with diamond bur
Scalpel blade (surgical knife)
Ultrasonic scaler
Curved scissors or acrylic bur on a slow-speed handpiece (Correct answer)

Correct answer: Curved scissors or acrylic bur on a slow-speed handpiece

Curved scissors or a slow-speed acrylic bur allow controlled, precise trimming of excess provisional material without damaging the surrounding soft tissue.

Question 74: During a protrusive movement of the mandible, which teeth ideally provide the primary guidance to disocclude the posterior teeth?

Maxillary and mandibular premolars
Maxillary and mandibular incisors (Correct answer)
Maxillary and mandibular canines
Maxillary and mandibular molars

Correct answer: Maxillary and mandibular incisors

In an ideal occlusion, protrusive movement (moving the jaw forward) results in contact between the incisal edges of the mandibular incisors and the lingual surfaces of the maxillary incisors. This contact and guidance should cause the posterior teeth to separate (disocclude). [12, 18, 20]

Question 75: Which of the following radiographic errors produces a clear, unexposed area on the processed film?

Overlapping
Film reversal
Double exposure
Cone cut (partial image) (Correct answer)

Correct answer: Cone cut (partial image)

A cone cut occurs when the PID is not centered over the film/sensor, leaving a clear, unexposed crescent-shaped area on the radiograph where X-rays did not reach.

Question 76: How should dental materials be handled to maintain their integrity?

By reusing materials once the patient has left
By leaving materials out in the open for easy access
By using them immediately after opening the packaging
By following storage instructions and using them within their expiration date (Correct answer)

Correct answer: By following storage instructions and using them within their expiration date

The integrity and effectiveness of dental materials are highly dependent on proper handling and storage. Following manufacturer's storage instructions, such as keeping them in a cool, dark place or specific humidity, prevents degradation. Additionally, using materials within their expiration date ensures their chemical properties are optimal for successful clinical outcomes and patient safety.

Question 77: Why is it necessary to maintain dental equipment manuals?

To increase the speed of procedures
To make the equipment easier to use
To ensure the equipment remains in warranty
To ensure proper operation, maintenance, and longevity of equipment (Correct answer)

Correct answer: To ensure proper operation, maintenance, and longevity of equipment

Dental equipment manuals contain crucial information regarding the safe operation, recommended maintenance schedules, troubleshooting guides, and technical specifications for each device. Referring to these manuals ensures that staff use the equipment correctly, perform necessary upkeep, and can address minor issues, thereby maximizing the equipment's lifespan and ensuring its reliable performance for patient care.

Question 78: Which of the following is a contraindication to rubber dam placement?

A patient with an existing composite restoration
A patient who expresses anxiety about dental treatment
A patient with multiple missing posterior teeth
A patient with severe nasal obstruction who cannot breathe through the nose (Correct answer)

Correct answer: A patient with severe nasal obstruction who cannot breathe through the nose

Severe nasal obstruction (from chronic congestion, asthma, or other conditions) prevents the patient from breathing comfortably with the rubber dam covering the mouth.

Question 79: Which shade selection guideline should be followed FIRST when choosing a composite shade?

Choose the lightest shade available
Match the shade to the patient's favorite color
Select the shade under bright operatory light
Evaluate shade on a hydrated tooth before isolation (Correct answer)

Correct answer: Evaluate shade on a hydrated tooth before isolation

Shade selection must be performed on a hydrated tooth before rubber dam or cotton roll isolation, as desiccation lightens tooth color.

Question 80: What is the importance of using lead aprons and thyroid collars during radiography?

To reduce the number of X-rays needed
To make the procedure more comfortable
To protect the patient from unnecessary radiation exposure (Correct answer)
To make the image clearer

Correct answer: To protect the patient from unnecessary radiation exposure

Lead aprons and thyroid collars are critical protective devices used during dental radiography. Their purpose is to shield sensitive areas of the patient's body, such as the reproductive organs and thyroid gland, from scatter radiation. This minimizes unnecessary radiation exposure, adhering to the ALARA (As Low As Reasonably Achievable) principle and ensuring patient safety during X-ray procedures.

Question 81: A dentist completes a deep cavity preparation on a molar with a suspected microscopic pulp exposure. Which material is specifically placed in a thin layer over the site to promote the formation of reparative dentin?

Zinc Oxide-Eugenol (ZOE)
Calcium Hydroxide (Correct answer)
Zinc Phosphate Cement
Glass Ionomer

Correct answer: Calcium Hydroxide

Calcium hydroxide is well-known for its high alkalinity (high pH) which provides an antibacterial effect and stimulates odontoblasts to form a dentin bridge, also known as reparative or tertiary dentin, over a pulp exposure.

Question 82: What is the purpose of the 'two-step putty-wash' PVS technique?

To reduce the need for tray adhesive
To capture both arches simultaneously in one appointment
To use two different brands of PVS for cost savings
To allow putty to set first, creating a rigid tray, then a thin wash captures fine detail (Correct answer)

Correct answer: To allow putty to set first, creating a rigid tray, then a thin wash captures fine detail

The set putty acts as a rigid custom tray, and the subsequent thin wash flows to capture precise marginal detail without distortion from tray flex.

Question 83: A patient requires a deep amalgam restoration on a molar. To provide thermal insulation for the pulp and to support the restoration during placement, the dentist will likely request which material to be placed in a thick layer?

A dentin sealer
A cavity sealant
A dental liner
A dental base (Correct answer)

Correct answer: A dental base

A dental base is placed in a thick layer on the floor of the cavity preparation. Its primary functions are to provide thermal insulation to protect the pulp from temperature changes and to be strong enough to support the occlusal forces absorbed by the final restoration.

Question 84: What is the main disadvantage of calcium hydroxide as a liner?

It inhibits composite polymerization
It dissolves over time and has poor compressive strength (Correct answer)
It is opaque and blocks light curing
It releases toxic fluoride ions

Correct answer: It dissolves over time and has poor compressive strength

Calcium hydroxide liners have low compressive strength and tend to dissolve if microleakage occurs, which can undermine the restoration.

Question 85: When using the acid-etch technique for composite bonding, phosphoric acid is applied to enamel for approximately:

2 minutes
60 seconds
5 seconds
15–30 seconds (Correct answer)

Correct answer: 15–30 seconds

Phosphoric acid (35–37%) is applied to enamel for 15–30 seconds to create adequate microporosities for resin tag formation.

Question 86: Which property of calcium hydroxide makes it effective for indirect pulp capping?

Its alkalinity stimulates the formation of reparative dentin (Correct answer)
Its radiopacity allows easy radiographic evaluation
High compressive strength
Its adhesion to enamel prevents microleakage

Correct answer: Its alkalinity stimulates the formation of reparative dentin

Calcium hydroxide's high pH (around 11–12) causes mild pulp irritation that stimulates odontoblasts to produce reparative (tertiary) dentin.

Question 87: A patient presents with a Class II, Division 2 malocclusion. Which of the following characteristics is a defining feature of this classification?

A posterior crossbite.
Protruded maxillary central incisors.
An open bite tendency.
Retroclined maxillary central incisors. (Correct answer)

Correct answer: Retroclined maxillary central incisors.

Angle's Class II, Division 2 malocclusion is characterized by a Class II molar relationship where the maxillary central incisors are retroclined, or tipped back towards the palate. The lateral incisors can be either normally inclined or proclined. [1, 3, 5, 7]

Question 88: Which of the following tray types is required when using polyvinyl siloxane for a full-arch impression?

Rimlock tray with adhesive (Correct answer)
Water-cooled metal tray
Stock perforated tray without adhesive
Thermoplastic disposable tray

Correct answer: Rimlock tray with adhesive

PVS requires mechanical or chemical retention to the tray; rimlock trays and/or tray adhesive prevent the set material from separating when the impression is removed.

Question 89: An air-water syringe tip used during sealant placement must be verified to be free of:

Air pressure
Fluoride particles
Sodium hypochlorite residue
Oil and water contamination (Correct answer)

Correct answer: Oil and water contamination

Compressor oil or water from the air-water syringe can contaminate the etched enamel surface and compromise the sealant bond.

Question 90: When finishing a composite restoration, the sequence of instruments should generally proceed from:

Polishing paste directly on uncured resin
Finer to coarser abrasives
Coarser to finer abrasives (Correct answer)
High-speed handpiece to pumice

Correct answer: Coarser to finer abrasives

Finishing proceeds from coarser instruments (carbide finishing burs, coarse discs) to progressively finer polishing instruments to achieve a smooth surface.

Question 91: What type of radiation produces the greatest risk for dental patients during X-ray exposure?

Primary radiation
Secondary radiation
Leakage radiation
Scatter radiation (Correct answer)

Correct answer: Scatter radiation

Scatter radiation, which is deflected in all directions from the patient's tissues, represents the greatest source of unintended exposure during dental radiographic procedures.

Question 92: Bloodborne pathogen training for dental employees must be provided:

Only when an exposure incident occurs
Once at initial employment only
Every five years
At initial employment and annually thereafter (Correct answer)

Correct answer: At initial employment and annually thereafter

OSHA's Bloodborne Pathogens Standard (29 CFR 1910.1030) requires employers to provide training at initial employment and annually to all at-risk employees.

Question 93: A filled resin sealant differs from an unfilled resin sealant primarily in that it:

Is less viscous and flows more easily into fissures
Does not require a curing light
Releases fluoride ions over time
Has greater wear resistance due to filler particles (Correct answer)

Correct answer: Has greater wear resistance due to filler particles

Filled sealants contain inorganic filler particles that increase wear resistance, making them better able to withstand occlusal forces.

Question 94: An EFDA is tasked with finishing and polishing a newly placed Class II amalgam restoration. Which of the following is a critical objective of this procedure?

To create a smooth, continuous margin that reduces plaque accumulation and prevents corrosion. (Correct answer)
To remove the smear layer from the dentin.
To lighten the color of the amalgam to match the tooth.
To increase the mercury content at the surface for added strength.

Correct answer: To create a smooth, continuous margin that reduces plaque accumulation and prevents corrosion.

Finishing and polishing an amalgam restoration is crucial for its long-term success. The process removes surface irregularities and creates a smooth cavosurface margin. This smoothness helps to reduce plaque retention, minimizes the risk of recurrent decay at the margins, and makes the restoration less susceptible to tarnish and corrosion.

Question 95: Which classification of furcation involvement indicates that the probe can enter the furcation but not pass through?

Class IV
Class II (Correct answer)
Class III
Class I

Correct answer: Class II

Class II furcation involvement means the probe penetrates into the furcation but cannot pass completely through to the other side.

Question 96: Dental dam application in EFDA scope primarily serves to:

Replace the need for local anesthesia
Reduce chair time by eliminating need for cotton rolls
Isolate the operative field, prevent aspiration, and improve visibility (Correct answer)
Substitute for rubber dam clamps

Correct answer: Isolate the operative field, prevent aspiration, and improve visibility

Dental dam isolates the tooth, protects the airway from debris, and provides a dry, visible field for restorative work.

Question 97: Which type of pit and fissure sealant requires a curing light to polymerize?

Self-cured (autopolymerizing) sealant
Light-cured (photopolymerized) sealant (Correct answer)
Fluoride varnish
Glass ionomer sealant

Correct answer: Light-cured (photopolymerized) sealant

Light-cured sealants contain a photoinitiator that activates only when exposed to a curing light of the appropriate wavelength.

Question 98: What is the function of a tray adhesive when used with elastomeric impressions?

To extend working time
To accelerate the setting reaction
To bond the impression material to the tray and prevent separation (Correct answer)
To improve the flow of material into sulcus areas

Correct answer: To bond the impression material to the tray and prevent separation

Tray adhesive creates a chemical and mechanical bond between the impression material and the tray walls, preventing distortion on removal.

Question 99: A 'high' amalgam restoration on occlusal check reveals a shiny spot on the restoration. This indicates:

Normal appearance of a new amalgam
A premature occlusal contact that needs adjustment (Correct answer)
The restoration was over-polished
The amalgam is fully cured

Correct answer: A premature occlusal contact that needs adjustment

A shiny spot (burnish mark) from articulating paper indicates a high spot that must be adjusted to prevent fracture or patient discomfort.

Question 100: When polishing teeth prior to sealant placement, which abrasive is recommended?

Sodium bicarbonate air-polishing powder
Oil-free, fluoride-free pumice or prophy paste (Correct answer)
Coarse diamond paste
Fluoride-containing prophy paste

Correct answer: Oil-free, fluoride-free pumice or prophy paste

Fluoride-free, oil-free prophy paste or pumice is used because fluoride can interfere with etching and oils can contaminate the bonding surface.

Expanded Function Dental Auxiliary (EFDA) Certification Exam

The EFDA certification exam assesses the knowledge and skills required for dental auxiliaries to perform expanded functions under the supervision of a dentist.

100

Questions

120 min

Time Limit

75%

To Pass

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