This study investigates the dependence of the cross section geometry of extruded dental
porcelain slurries on the rheological property of the slurry and the extrusion conditions. It is
found that a pseudoplastic slurry is a basic requirement for obtaining extruded lines with
rectangular cross sections. The cross section geometry of the extrudate is also strongly affected
by extrusion parameters including the extrusion nozzle height, nozzle moving speed, and
extrusion rate. Proper combinations of these extrusion parameters are necessary in order to
obtain extrudates with near rectangular cross sections. The results obtained have been explained
in terms of the interactions among the rheological properties of the slurry, the shear rate imposed
on the slurry during extrusion, the wettability of the slurry on the substrate, and the forced flow
of the slurry during extrusion.The authors gratefully acknowledge financial support provided by
the National Science Foundation under Grant Nos: DMI-9908249 and DMI-0218169.Mechanical Engineerin