Abstract: The present invention provides a novel extrusion apparatus including a flow channel having a modified preland channel that functions as a flow transition zone. The flow transition zone changes the widthwise flow volume of a stream passing therethrough so as to provide for substantially equal flow volume of the stream across the flow channel width as the stream exits from the transition zone.

Abstract: The corrosion and staining of unlined aluminum tube surfaces by dentifrices such as toothpastes, particularly when the dentifrices contain therapeutic agents, is substantially prevented by incorporation into the dentifrice of a controlled amount of an alkaline earth metal ion such as calcium ion, in the range of 0.005-0.2 weight percent, and preferably in the range of 0.005-0.070 weight percent of the dentifrice. The alkaline earth metal may be provided from any water soluble alkaline earth metal salt or as a reaction product of the alkaline earth metal salt with an amorphous silica abrasive and/or thickener.