Endodontic Materials Flashcards

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

Answer: Excellent biocompatibility and sealing ability in the presence of moisture

MTA's biocompatibility, ability to set in moisture, and superior marginal seal make it ideal for perforation repair.

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

Answer: 0.02 mm/mm

ISO specification 6877 requires standardized gutta-percha cones to have a 0.02 mm/mm taper matching standardized instruments.

Calcium hydroxide exerts its antimicrobial effect primarily through:

Answer: High pH causing protein denaturation and enzyme disruption

Calcium hydroxide's pH of approximately 12.5 causes protein denaturation and disrupts enzyme activity in bacterial cells.

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

Answer: Resin-based sealers (AH Plus)

AH Plus epoxy resin sealer exhibits minimal volumetric shrinkage upon polymerization compared to other sealer types.

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

Answer: Chloroform

Chloroform is the most effective solvent for dissolving gutta-percha, though its use is restricted in some countries due to carcinogenicity concerns.

Bioceramic sealers achieve their adhesion to dentinal walls primarily through:

Answer: Formation of hydroxyapatite crystals that bond to dentin

Bioceramic sealers react with water in dentinal tubules to form hydroxyapatite, which chemically bonds to the dentin structure.

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

Answer: Free eugenol

Free unbound eugenol is primarily responsible for the cytotoxicity of ZOE sealers, as it can irritate periapical tissues.