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1.     All flaws are duplicated from: Impression to model.

2.     The 2 most important properties of die material are: Accuracy & dimensional stability.

3.    Gypsum products are: Calcium sulfate

4.    Type of reaction in gypsum products: chemical, exothermic, gives off heat.

5.    List from best to worst the types of gypsum products and their features:

a.    High strength dental stone (die stone) regularly shaped and less porous. More dense.

b.    Dental stone (yellow)

c.    Model Plaster (white) more irregularly shaped & more porous. Req’s more H2O to mix because of pores. Add plaster to H2O

6.     When setting time is nearing what is there a loss of? Gloss.

7.     Final setting tie is when: material can be separated from impression.

8.    The number of bubbles on a model is the function of: wettability of impression material.

9.    The dry strength is: twice as strong as the wet strength.

10.   Maximum strength is reached when: material is dry.

11.   All gypsum products undergo setting: expansion.

12.    Water to powder ratio for plaster: 45mL/100g

                                Dental stone: 30mL/100g

                                Die stone: 20mL/100g

13.Increase H2O/powder= thinner mix = longer set time =A decrease in strength.

14.Increase rate of spatulation = decrease in working time.

15.Increase in temperature = increase rate of setting time

16.Air in alginate results in bubbles (positives)

17.Air in stone results in voids in models.

Disclaimer: These notes were copied and pasted from files sent to me by Andrea.  They have not been reviewed for errors. You are responsible for checking out the information to verify the accuracy. This site, Amy Nieves and Andrea are not responsible for typographical errors.