Dental Plaster Write a short note on setting of dental plaster. Answer: The setting of Dental Plaster: When 1 g mol of calcium sulfate hemihydrates reacts with 1.5 g mol of water, the hemihydrates revert to dihydrate forming 1 g mol of calcium sulfate dihydrate by hydration, with liberation of 3900 calories of heat. Here the heat which is evolved in reaction is equal … [Read more...] about Dental Plaster
Dental Materials
Initial And Final Setting Times
Initial And Final Setting Times Question 1. Define the initial and final setting time of gypsum products. State their importance. Or Enumerate the factor that controls the setting time of gypsum hemihydrates. Or Answer: Setting time: The time elapsing from the beginning of mixing till the material hardens is called as “setting time”. Initial Setting Time: The time … [Read more...] about Initial And Final Setting Times
Gypsum Products: Uses & Composition
Gypsum Products: Uses & Composition Enumerate the gypsum products used in dentistry. Or Tabulate their difference for physical properties, composition, and uses. Or Write about different types of gypsum products Answer: Gypsum is a mineral mined in various parts of the world. Gypsum is also an industrial by-product. Gypsum was first found in mines around … [Read more...] about Gypsum Products: Uses & Composition
Classification Of Investment Materials
Classification Of Investment Materials Explain the setting expansions of investment materials. Describe them in details. Answer: Setting Expansion of Investment Materials: Normal Setting Expansion: A mixture of silica and dental stone results in setting expansion which is more than when the gypsum product is used alone. The silica particles probably interfere … [Read more...] about Classification Of Investment Materials
The Hygroscopic Setting Expansion Of Gypsum
The Hygroscopic Setting Expansion Of Gypsum Write in detail about hygroscopic expansion. Answer: Hygroscopic Setting Expansion: When a gypsum product is placed underwater before the initial set stage, a greater expansion is seen. This is due to hygroscopic expansion. When expansion begins, externally available water is drawn into pores forming in the setting mass and … [Read more...] about The Hygroscopic Setting Expansion Of Gypsum