ABE Endodontic Materials 2

Question 1

Which property of mineral trioxide aggregate (MTA) makes it particularly suitable as a perforation repair material?

Accepted Answer

Excellent biocompatibility and sealing ability in the presence of moisture

Answer

High solubility in tissue fluids

Answer

Rapid setting time of under 5 minutes

Answer

Antibacterial activity against E. faecalis

Question 2

The International Organization for Standardization (ISO) specification for gutta-percha points requires the taper of standardized cones to be:

Accepted Answer

0.02 mm/mm

Answer

0.04 mm/mm

Answer

0.06 mm/mm

Answer

0.08 mm/mm

Question 3

Calcium hydroxide exerts its antimicrobial effect primarily through:

Accepted Answer

High pH causing protein denaturation and enzyme disruption

Answer

Chelation of bacterial cell wall components

Answer

Release of fluoride ions into dentinal tubules

Answer

Inhibition of bacterial DNA replication

Question 4

Which endodontic sealer has the lowest shrinkage upon setting among the following options?

Accepted Answer

Resin-based sealers (AH Plus)

Answer

Zinc oxide eugenol sealers

Answer

Calcium silicate-based sealers (Biodentine)

Answer

Glass ionomer sealers

Question 5

The solvent most commonly used to dissolve gutta-percha during retreatment is:

Accepted Answer

Chloroform

Answer

Sodium hypochlorite

Answer

EDTA

Answer

Hydrogen peroxide

Question 6

Bioceramic sealers achieve their adhesion to dentinal walls primarily through:

Accepted Answer

Formation of hydroxyapatite crystals that bond to dentin

Answer

Micromechanical interlocking after acid etching

Answer

Chemical bonding via silane coupling agents

Answer

Van der Waals forces at the sealer-dentin interface

Question 7

Which component of zinc oxide eugenol (ZOE) sealers is responsible for its cytotoxic effects?

Accepted Answer

Free eugenol

Answer

Zinc oxide particles

Answer

Rosin accelerators

Answer

Canada balsam