The ornamental design for a magnetictoothbrushsystem, as shown and described.
FIG. 1 is a perspective view of the magnetic toothbrush system, displaying the option of storing a tube of toothpaste on the absorbent shelf, which embodies my design;
FIG. 2 is a perspective view;
FIG. 3 is a front view;
FIG. 4 is a left side view;
FIG. 5 is a top view;
FIG. 6 is a right side view;
FIG. 7 is a back view illustrating adhesive portions;
FIG. 8 is a bottom view; and,
FIG. 9 is a back view of a magnetic toothbrush, shown separately for clarity of illustration.
The broken line showing of a toothpaste tube is illustrated for the purpose of showing environmental structure, which forms no part of the claimed design.