The ornamental design for an oral brushhead, as shown and described.
FIG. 1 is an isometric view of the oral brush head showing the new design, the broken lines showing a second brush head and a handle being included for the purpose of illustrating environmental structure that forms no part of the claimed design;
FIG. 2 is an enlarged isometric view of the oral brush head of FIG. 1;
FIG. 3 is a front elevation view of the oral brush head of FIG. 2;
FIG. 4 is a rear elevation view of the oral brush head of FIG. 2;
FIG. 5 is an elevation view of one side of the oral brush head of FIG. 2;
FIG. 6 is an opposite side elevation view of the oral brush head of FIG. 2;
FIG. 7 is a top plan view of the oral brush head of FIG. 2; and,
FIG. 8 is a bottom plan view of the oral brush head of FIG. 2.