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Background: Alginate impression is a common dental polymeric material, presented as powder to be mixed with water. Aim: 1. To analyze the effect of alginate powder/water ratio variation on viscosity, tear strength and detail reproduction by <i>in vitro</i> tests, and 2. To evaluate this variation’s effect on patients’ impressions. Materials and methods: Two commercial alginate products were mixed in different viscosities. Viscosity was measured by a viscometer. For the tear strength test, V-shaped specimens were used. For detail reproduction, a die with three scribed lines was used. Clinical dental impressions were examined by stereomicroscope. Results: The alginate specimens mixed with a higher powder/water ratio showed a higher viscosity and tear strength compared to those with a lower powder/water ratio. Both alginate mixtures reproduced two scribed lines in a detail reproduction test. On the other hand, no clear clinical difference was detected when examining dental impressions mixed with a different powder/water ratio. Conclusion: Although increasing the powder/water ratio of mixed alginate raised the resultant viscosity and tear strength by an <i>in vitro</i> test, clinically, no clear difference in tearing was detected. Detail reproduction was minimally affected by the variation in powder/water ratio.