Mixed Deck — All EFDA Topics Flashcards

A Class V composite restoration on the facial surface of tooth #9 requires etching of:

Answer: Both enamel and dentin (total-etch technique)

Total-etch technique involves etching both enamel and dentin to maximize bond strength, especially at cervical margins where enamel may be minimal.

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

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.

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

Answer: Using latex gloves during mixing

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

Which property of dental amalgam is described as the tendency to expand or contract under stress without fracturing?

Answer: Creep

Creep is the slow plastic deformation of amalgam under sustained compressive load, which can lead to marginal breakdown and ditching over time.

When evaluating a completed sealant clinically, which finding would require immediate repair or replacement?

Answer: An explorer tip catching or dropping into a void within the sealant

An explorer catching in a void indicates incomplete coverage or air entrapment, creating a site for plaque accumulation and caries initiation under the sealant.

Which factor most significantly affects the long-term retention rate of pit and fissure sealants?

Answer: Moisture control during placement

Adequate moisture control is the single most critical factor in sealant retention because contamination prevents proper bonding to etched enamel.

The 212 'butterfly' rubber dam clamp is specifically designed for use on:

Answer: Partially erupted or severely broken-down teeth with minimal clinical crown

The 212 clamp has an inverted bow design that allows it to engage tooth structure at or slightly below the gingival margin, making it useful for partially erupted or broken-down teeth.

When would it be CONTRAINDICATED to place a pit and fissure sealant?

Answer: A tooth with an open, shallow fissure that self-cleanses easily

Teeth with open, shallow fissures that can be cleaned by a toothbrush are self-cleansing and do not benefit from sealant placement.

The 'C-factor' (configuration factor) in composite restorations refers to:

Answer: The ratio of bonded to unbonded surfaces affecting shrinkage stress

A high C-factor (more bonded walls than free surfaces) increases polymerization shrinkage stress, which can debond the restoration or fracture enamel.

Which of the following best describes the 'indirect' method of provisional crown fabrication?

Answer: The crown is fabricated on a diagnostic cast outside the mouth

The indirect method involves fabricating the provisional on a study model or working cast outside the patient's mouth, reducing intraoral exposure to heat and monomer.

How does infection control apply to digital radiography?

Answer: By following the same infection control procedures as for traditional radiography

While digital radiography uses sensors instead of film, the principles of infection control remain identical to traditional radiography. Digital sensors and their cables still come into contact with oral fluids, necessitating barrier protection and disinfection after each use. This ensures the prevention of cross-contamination and maintains a sterile environment, regardless of the imaging technology used.

During a coronal polish, a patient has intrinsic tetracycline staining. The EFDA should know that:

Answer: Coronal polishing cannot remove intrinsic tetracycline stains

Intrinsic stains are incorporated within the tooth structure and cannot be removed by external polishing procedures.

Dental dam application in EFDA scope primarily serves to:

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.

When placing a matrix band for an amalgam Class II restoration, the band should be contoured to create:

Answer: A convex proximal contour with a tight contact

The matrix band must be burnished to create a convex proximal surface and a proper tight contact to prevent food impaction.

The EFDA is preparing to place a base under a deep amalgam restoration. Which base material has the best pulp-protective (obtundent) properties?

Answer: Calcium hydroxide

Calcium hydroxide stimulates reparative dentin formation and has direct pulp-capping and obtundent properties near the pulp.

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

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.

What is the recommended curing light distance from the composite surface during polymerization to ensure adequate depth of cure?

Answer: As close as possible without touching, within 1-2 mm

Holding the curing light tip within 1-2 mm of the composite surface maximizes light intensity and ensures adequate depth of cure.

Which symptom is MOST consistent with microleakage around a composite restoration?

Answer: Recurrent caries at the restoration margin months later

Microleakage allows bacteria and oral fluids to seep under the restoration margin, leading to secondary (recurrent) caries over time.

In centric occlusion, the mandibular buccal cusps occlude in which fossae of the maxillary posterior teeth?

Answer: Central fossae

The mandibular buccal cusps (centric holding cusps) occlude in the central fossae of the maxillary posterior teeth in ideal centric occlusion.

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

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.