Dental Materials Flashcards
7 cards from real Dental practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Dental Materials flashcards as text
Which dental cement is considered most biocompatible with the pulp tissue?
Answer: Zinc oxide eugenol (ZOE) cement
Zinc oxide eugenol cement is highly biocompatible because eugenol has a sedative, obtundent effect on the pulp and the material has a near-neutral pH.
What does polymerization shrinkage of composite resin result in clinically?
Answer: Microleakage and marginal gap formation
As composites shrink toward the light source during polymerization, gaps can form at the restoration margins, leading to microleakage and potential secondary caries.
What is the primary advantage of polyvinyl siloxane (PVS) impression material over polysulfide?
Answer: Superior dimensional accuracy and stability
PVS impressions are highly dimensionally accurate and stable, allowing casts to be poured days after the impression is taken without significant distortion.
Which type of dental porcelain is fused directly to a metal substructure in a PFM crown?
Answer: Feldspathic porcelain
Feldspathic porcelain is the traditional veneering porcelain used in PFM restorations because it bonds well to the metal oxide layer on the substructure.
Increasing the water-to-powder ratio of a gypsum mix will have which effect on the set product?
Answer: Decreased strength and increased setting time
Excess water dilutes the reaction, slowing setting time and leaving more porosity in the set material, resulting in reduced compressive strength.
What is the purpose of the smear layer removal (etching) step in total-etch bonding systems?
Answer: To remove debris and open dentinal tubules for resin tags and hybridization
Acid etching removes the smear layer and demineralizes superficial dentin, creating microporosities for resin infiltration and a hybrid layer for micromechanical bonding.
Which property of dental wax makes it suitable for use in bite registration?
Answer: Plasticity at mouth temperature and rigidity at room temperature
Bite registration wax softens at oral temperature to record occlusal relationships accurately and then hardens at room temperature to preserve the registration.