An improved dental tape treated with a substantive coating containing a crystal control substance, wherein said coating is: saliva soluble, substantially crystal-free, with a flaking value of less than about 20 and a release value of about 100. The MgO layer is formed by means of the ECR sputtering method. A controller is adapted to control a supply of a coloring agent from said coloring agent supply into said extrusion container in accordance with a selected brick type. The URL may identify a stored media clip, or may contain information from which a video clip can be recreated.