Dental Materials and Biomaterials Flashcards

Which property of an ideal implant biomaterial is described as the ability to integrate with surrounding bone without fibrous encapsulation?

Answer: Osseointegration

Osseointegration, defined by Brånemark, describes the direct structural and functional connection between living bone and the implant surface without intervening soft tissue.

Surface roughness of titanium implants is most commonly increased by which process to enhance osseointegration?

Answer: Sandblasting and acid etching (SLA)

Sandblasted, large-grit, acid-etched (SLA) surfaces increase microroughness significantly, improving bone-to-implant contact and osseointegration speed.

Which endodontic sealer component is responsible for the antimicrobial activity of zinc oxide eugenol sealers?

Answer: Eugenol

Eugenol is the primary antimicrobial agent in ZOE sealers, inhibiting bacterial growth through disruption of lipid membranes.

The fatigue failure of a metal restoration is best described as failure due to:

Answer: Repeated cyclic stresses below the proportional limit

Fatigue failure occurs from repeated cyclic loading at stresses well below the material's ultimate strength, eventually causing crack initiation and propagation.

Which ion released from glass ionomer cement is primarily responsible for its cariostatic properties?

Answer: Fluoride

Fluoride ions released from glass ionomer cement inhibit bacterial metabolism and promote remineralization of adjacent tooth structure.

What is the most important clinical reason to use a cavity varnish under amalgam restorations when zinc phosphate cement is not used?

Answer: Reduce microleakage before amalgam seals margins naturally

Cavity varnish seals dentinal tubules and reduces early microleakage while amalgam undergoes corrosion-based marginal sealing over the first weeks.

Which agar impression material property makes it necessary to use a water-cooled tray during impression taking?

Answer: It undergoes sol-gel transition controlled by temperature

Agar (reversible hydrocolloid) converts from sol (fluid) to gel (solid) via cooling; a water-cooled tray circulates cold water to set the material consistently in the mouth.