The aim of the study was to investigate the dimension stability of four different alginate materials under storage conditions. The weight of alginate is equivalent to the dimension. So that the water loose depends to the weight and so to the dimension.
Methods:
Four different alginates were mixed by hand and filled into petri dishes. The petri dishes had a diameter of 50mm and a hight of 115mm. We analyzed two groups. One group was stored under storage conditions without a zip bag and the second group under storage conditions with a zip bag. The weight of every petri dish was measured after 0, 0,5, 1, 1,5, 2, 3, 4, 6, 24 and 48 hours. The storage room had a temperature between 18°C and 25°C.
Results:
The results of the investigation showed that nearly every alginate hold the wheight in the first two hours without a zip bag and the first 4-6 hours with a zip bag. The weight difference for Group one (without a zip bag) was lower than 2,4% (< 0,6g/25g) in the first two hours and for Group two lower than 1,6% (< 0,4g/25g) in the first 6 hours. So that he water loose was very low under these circumstances.
Conclusions:
The use of alginat impression material is very common. The mechanical handling ist very simple and it is very economical. Under real conditions in dental practices and clinics the duration of storage depends between several minutes to hours. Usually the producer advices the user to pour out the impression in between the first 20 minutes. With our study we could show that a lot of alginate impression materials can be stored for hours without loosing the dimension.