Water Temperature Influence on Jeltrate Alginate Impression Material's Setting Time

Objective: The purpose of this experiment was to qualitatively examine the influence that water temperature has on the setting time of Jeltrate Alginate Regular Set using a simple experimental design and basic materials.

Methods: The impression material was spatulated with temperatures of water at approximately 7°C, 19.5°C and 45°C. A timer was started upon addition of the water to the powder and the mixture was spatulated until homogenous in consistency. A marble was continuously placed on and removed from the surface of the alginate material until no visible depression was evident at which point the mixture was considered set. For each water temperature investigated three trials were conducted and the mean setting time was calculated.

Results: Mixing the impression material with 7°C water resulted in a mean setting time of 5.56±0.46 minutes. With 19.5°C water the mean setting time was reduced to 3.78±0.13 minutes. Mean setting time decreased to 2.39±0.23 minutes when 45°C water was used.

Conclusion: An inverse relationship between the setting time of the impression material and the water temperature used was observed. This pattern was attributed to Arrhenius kinetics involving collision theory and activation energy as they relate to the chemical reactions occurring when alginate impression material is mixed with water. Increasing the water temperature used in the preparation added more thermal energy to the system increasing collisions between the reagents while also amplifying their activation energy. This combined influence allowed the impression material to undergo the reactions at a faster rate, thereby reducing the material's setting time.