ABE Endodontic Materials 4

Question 1

Chlorhexidine gluconate is used as an endodontic irrigant because it provides:

Accepted Answer

Substantivity through prolonged antimicrobial activity

Answer

Superior tissue dissolution compared to NaOCl

Answer

Effective smear layer removal

Answer

Complete elimination of the smear layer

Question 2

The setting reaction of calcium silicate-based cements (MTA, Biodentine) requires:

Accepted Answer

Water as a reactant to form calcium silicate hydrate and calcium hydroxide

Answer

Anhydrous conditions for polymerization

Answer

UV light activation

Answer

A catalyst such as eugenol

Question 3

Which property distinguishes resilon from gutta-percha as an obturation material?

Accepted Answer

Ability to bond chemically to resin-based sealers

Answer

Higher biocompatibility with periapical tissues

Answer

Greater resistance to retreatment solvents

Answer

Lower coefficient of thermal expansion

Question 4

Sodium hypochlorite at 5.25% concentration injected inadvertently beyond the apex may cause:

Accepted Answer

Severe tissue injury with pain, edema, and possible ecchymosis

Answer

Permanent nerve damage requiring surgical intervention

Answer

Asymptomatic resolution within 24 hours

Answer

Mild inflammation that resolves with analgesics in 2 hours

Question 5

The primary advantage of using a fiber post over a cast metal post-and-core is:

Accepted Answer

Modulus of elasticity similar to dentin, reducing root fracture risk

Answer

Superior retention in the root canal space

Answer

Lower cost per unit fabrication

Answer

Greater resistance to microleakage at the post-cement interface

Question 6

Premixed bioceramic putty materials used in endodontics are typically packaged in syringes because they:

Accepted Answer

Do not set until exposed to moisture, remaining stable in hermetic packaging

Answer

Require refrigeration to remain stable

Answer

Must be heated before use to reduce viscosity

Answer

Contain pre-mixed hardeners requiring immediate use

Question 7

Which endodontic sealer is contraindicated in patients with known allergy to its primary organic component?

Accepted Answer

Zinc oxide eugenol sealer – contraindicated in patients allergic to clove oil/eugenol

Answer

AH Plus (epoxy resin sealer) – contraindicated in patients allergic to bisphenol A

Answer

Glass ionomer sealer – contraindicated in patients allergic to fluoride

Answer

Bioceramic sealer – contraindicated in patients allergic to calcium