The effect of cold temperature mixing on the properties of zinc phosphate cement.
A series of proprietary zinc phosphate cements were evaluated after mixing on glass slabs at three different temperatures, 23 degrees, 6 degrees and -10 degrees C. Working time, setting time, diametral tensile strength, compressive strength and solubility were investigated. From the results of the tests the following conclusions were made: 1) As the temperature of the mixing slab was decreased, the amount of powder required to maintain a constatnt viscosity increased. 2) Compressive, tensile, and solubility values remained constant as the temperature of the mixing slab was decreased provided a consistent viscosity was maintained. 3) Mixing zinc phosphate cement substantially below the dew point is an acceptable practice provided the powder/liquid ratio is modified accordingly. 4) Although the setting time of zinc phosphate cement generally remained constant at temperatures below 6 degrees C, the working time continued to increase at -10 degrees C. 5) Mixing zinc phosphate cemment on a cold mixing slab increases the working time on the glass slab and decreases the setting time in an oral environment. Both of these alterations are clinically beneficial to the orthodontist.
D003080:Cold Temperature; D012995:Solubility; D013314:Stress, Mechanical; D013997:Time Factors; D014783:Viscosity; D015036:Zinc Phosphate Cement
D015036:Zinc Phosphate Cement