Exam 9: Model and Die Materials

Proper wetting occurs when gypsum is poured against a _____-based impression material such as _____.

The purpose of the vibrating table is to:

Hardness and abrasion resistance is especially important for:

Which of the following statements is true regarding disinfection of a gypsum model?

As compressive strength of gypsum materials increases,_____ increases.

When the alginate dries out before it is poured:

Which of the following statements is(are)correct about making models,casts,and dies?

Which of the following chemicals is an effective accelerator for gypsum materials?

If the temperature of the water used to mix gypsum materials is raised up to body temperature (37.5° C),the setting time decreases.However,if water temperature is raised above 37.5° C,the setting time will increase.

Which of the following statements is true of the production of dental stone?

Accelerators are chemicals that _____ the rate of setting and _____ the time of setting.

Epoxy materials are compatible with most of the elastomeric impression materials.Epoxy materials can be used with alginates.

Clinically,the best way to determine the final setting time is:

High-strength stone requires the least amount of excess water,because the crystals are:

Gypsum model and die materials exhibit _____ in contrast to epoxy model and die materials.

The final setting time is defined as:

The inherent roughness limits the ability of gypsum materials to capture the finest details of impressions.Reproduction of detail is sufficient for most applications.

When gypsum is mixed by hand,the mass is stirred with a spatula at a rate of about _____ revolution(s)per second for _____.

Which of the following statements is true of the handling of an alginate impression?

Dies of epoxy for use in fabrication of crowns,bridges,and inlays can be poured into alginate.Epoxy dies are tougher and more abrasion resistant than high-strength stone dies,and they are more accurate and stable dimensionally.