The present invention relates to compounds of the Formula Iwherein R1, R2, R3, R4, R6, R7 and A are as defined. The first body comprises a frame for location about at least one of a molar or a premolar of user, as a first bite pad between upper teeth and lower teeth. By dissolving the first layer at least partially, at least a portion of the liquid can flow from the first to the second reservoir.