Journal of Dental Research, Vol 55, 223-228, Copyright © 1976 by International & American Associations for Dental Research Online Journals
An apparatus for measuring the rheological properties of dental materials
E. C. Combe and J. B. Moser
An indirect extrusion capillary viscometer has been developed. This has
been tested for nonsetting Newtonian fluids and was found to give results
close to, but slightly lower than the actual viscosity. The same apparatus
has been successfully applied to a non-Newtonian fluid to determine the
dependence of viscosity on shear rate. The technique described should meet
the requirements for assessing the rheological characteristics important in
the mixing and setting of dental materials. The developed viscometer must
be coupled with a sensitive mechanical testing machine capable of an
adequate range of crosshead speeds that can be changed rapidly. By
obtaining force vs time curves at different shear rates for setting
materials, viscosity can be calculated as a function of time. Also, the
viscosity at any given time during the setting process can be calculated as
a function of shear rate. This chould be of aid in the interpretation of
changes in rheological properties during setting of dental materials.
