Dental Materials Science Flashcards
7 cards from real DMD 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 Science flashcards as text
Which ADA Type of gypsum product has the highest compressive strength and is most suitable for fabricating dental dies?
Answer: Type IV — Die stone
Type IV die stone (high-strength dental stone) has the highest compressive strength due to its low water-to-powder ratio and is the preferred material for accurate dies.
The elastic modulus (Young's modulus) of a dental material represents:
Answer: The ratio of stress to strain within the elastic range
Young's modulus equals stress divided by strain within the elastic (proportional) range, and it quantifies the stiffness or rigidity of a material.
Glass ionomer cement achieves adhesion to tooth structure primarily through which mechanism?
Answer: Chemical ionic bonding with calcium in hydroxyapatite
Glass ionomer cement bonds chemically through exchange of ions between the polyalkenoic acid and calcium ions in the hydroxyapatite of tooth structure.
What is the primary clinical significance of fluoride release from glass ionomer cements?
Answer: Provides secondary anticariogenic protection at restoration margins
Fluoride released from glass ionomer cements inhibits bacterial metabolism and promotes remineralization, providing secondary caries prevention at the margins.
In porcelain-fused-to-metal (PFM) restorations, which type of ceramic is layered directly onto the metal coping?
Answer: Feldspathic porcelain
Feldspathic porcelain is used in PFM restorations because its thermal expansion coefficient is compatible with dental metal alloys, ensuring a durable bond.
The setting expansion of dental stone during gypsum product fabrication is clinically important because it:
Answer: Compensates for the solidification shrinkage of gold casting alloys
The slight setting expansion of dental stone compensates for the thermal contraction (solidification shrinkage) that occurs when molten gold alloys solidify in the casting mold.
Which elastomeric impression material offers the greatest dimensional accuracy and long-term stability for fixed prosthodontic impressions?
Answer: Polyvinyl siloxane (addition silicone)
Polyvinyl siloxane (addition silicone) provides the highest accuracy and dimensional stability because it undergoes minimal dimensional change over time with no byproducts released.