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The Linear Setting Expansions of the Dental Stone and Whose Initial Setting Times

Saip Denizoglu,Nuran Yan?koglu*,Bulent Baydas

Objectives: The aim of this study is to compare the setting time, which is shortened by using various different slurry water concentrations with the changes of setting expansions of plaster and stones.

Materials and Methods: In this study, two improved dental stones were used to fabricate master casts and dies. The tested fabrications were BegoStone, Moldano and plaster of paris. Three specimens per stone were fabricated to be 100 mm in length and triangular in cross-section (33×50×33 mm). Mixing was performed with distilled water, tap water and 2% and 16% slurry water. The mixtures were poured into an electronic expansion-measuring device, and setting expansion values were continuously measured and recorded for 24 hours.

Results: The mixtures were poured into an electronic expansion-measuring device, and setting expansion values were continuously measured and recorded for 24 hours. In the first five hour period not only did the initial setting time shorten, the amount of the expansion also increased to a considerable level.

Conclusions: Within the context of this study, it was observed that not only did the initial setting time shorten but the amount of the expansion also increased to a pronounce level in the first 24 hours when slurry water was used. Unexpected results may be faced when indirect dental restorations are done within this period of time.

Clinical Relevance: Dental gypsum products must have specific setting times and setting expansion. The setting rate for gypsum materials can be accelerated by various methods.