The ornamental design for a dentalinstrument mount for a prophy paste container, as shown and described.
FIG. 1 is an upper perspective view of a dental instrument mount for a prophy paste container having a receptacle to receive a rectangular prophy paste container, the lower mounting portion having dual mounts to permit the selective support of the dental instrument mount on differently sized dental instruments;
FIG. 2 is a reduced end view of the dental instrument mount shown in FIG. 1, the opposing end view of the dental instrument mount being identical;
FIG. 3 is a reduced top plan view thereof;
FIG. 4 is a reduced side view of the dental instrument mount shown in FIG. 1, the opposing side view of the dental instrument mount being identical; and,