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24 Cards in this Set
- Front
- Back
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How does fluoride accumulate in plaque?
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Saliva
Gingival Fluid Diet Topical Fluoride Demineralizing Enamel Sources |
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What dental materials release Fluoride?
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Silicate
Glass Ionomer Silicophosphates Compomers Resins Sealants Gum Toothpastes |
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Fluoride release is _____ for years, but rate of release _____ over time.
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Detectable, decreases
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What is the change in fluoride content and the change in acid solubility for Silicate without fluoride?
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0%, 20%
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What is the change in fluoride content and the change in acid solubility for Silicate with fluoride?
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3500%, -40%
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What is the change in fluoride content and the change in acid solubility for Zinc silicophosphate?
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5000%, -50%
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What is the change in fluoride content and the change in acid solubility for Glass Ionomer?
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3000%, -30%
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What is in the powder of Silicate cements?
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- Glass SiO2
- Al2O3 - Fluoride and Calcium Compounds |
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What are some examples of the fluoride and calcium compounds that are found in silicate cements?
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NaF
CaF2 Na3AlF6 Ca(H2PO4)2H2O CaO |
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At what temp do the fluxing compounds in silicate cements fuse?
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1400 degrees C
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How does setting occur in silicate cements?
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Calcium, Aluminum and fluoride ions are leached by acid attack and form phosphates in cement matrix
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What are the factors involved in selecting a dental cement?
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- Physical and biological properties
- Handling Characteristics - Cost |
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What are the factors involved in handling characteristics?
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- Working and setting times
- Ease of manipulation - Pre-dispensed doses - Ease of removal of excess material |
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How are dimensional changes during setting minimized?
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Through proper isolation and protection
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What are the specific uses of zinc phosphate cements?
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final cementation, high-strength base
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What are the fusing temps of zinc oxide and magnesium oxide in zinc phosphate cements?
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Between 1000 and 1400 degrees C
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What might the powders of zinc phosphate cements contain?
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Silica
Alumina About 10% Stannous fluoride |
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_____ regulates the ionization of the liquid in zinc phosphate and influences the _____.
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Water, setting reaction
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What is the pH in a zinc phosphate cement setting reaction?
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1.6 two minutes after mixing
4 after one hour 6-7 after 24 hours |
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What are the main powder components of zinc polycarboxylate cements?
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zinc oxide
sometimes magnesium Aluminum bismuth oxides |
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What are formed by interaction between carboxyl groups of adjacent polyacid chains and metal ions?
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Cross-linked zinc and magnesium polycarboxylate salts
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What occurs after the hydration of the freeze-dried powder in zinc polycarboxylate cements?
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Acid-base reactions
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What does the set zinc polycarboxylate cements consist of?
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Amorphous salt matrix
partially reacted powder particles loosely and tightly bound H2O |
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What is the working time and setting time of zinc polycarboxylate cements when compared to zinc phosphate cements?
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Zinc Polycarboxylate Cement
WT: 2.5 min. ST: 6 min. Zinc Phosphate Cement WT: 5 min. ST: 5.5 min. |
