Dental Biomaterials Flashcards
7 cards from real ADEX 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 Biomaterials flashcards as text
Which type of dental cement is most biocompatible and commonly used as a base under composite restorations?
Answer: Glass ionomer cement
Glass ionomer cement is highly biocompatible, bonds chemically to tooth structure, and releases fluoride, making it ideal as a base under composite restorations.
What is the primary setting reaction of zinc phosphate cement?
Answer: Acid-base reaction between zinc oxide powder and phosphoric acid liquid
Zinc phosphate cement sets via an exothermic acid-base reaction where zinc oxide reacts with phosphoric acid to form zinc phosphate crystals.
The term 'work time' in dental materials refers to:
Answer: Time available for manipulation after mixing before setting begins
Work time is the period after mixing during which the material can be manipulated and placed before it begins to set.
Which property describes a material's ability to withstand repeated loading without fracturing?
Answer: Fatigue resistance
Fatigue resistance is a material's ability to endure cyclic or repeated stresses over time without failure.
Resin-modified glass ionomer (RMGI) differs from conventional glass ionomer primarily because it:
Answer: Has a dual-cure mechanism including light-activated resin
RMGI incorporates HEMA resin monomers that allow light-curing in addition to the acid-base setting reaction of conventional glass ionomer.
What does the term 'coefficient of thermal expansion' mean in the context of dental restorations?
Answer: Change in material volume per unit temperature change
The coefficient of thermal expansion measures how much a material expands or contracts per degree of temperature change, and mismatch with tooth structure can cause microleakage.
Which bonding mechanism does polycarboxylate cement use to adhere to tooth structure?
Answer: Chelation of polyacrylic acid with calcium ions in enamel and dentin
Polycarboxylate cement forms a true chemical bond through chelation between its polyacrylic acid and calcium ions in the tooth's hydroxyapatite.