The present disclosure provides a new design for a toothbrush having a detachable bristle head portion that interlocks with a bristle frame mounting portion to form a watertight seal. The detachable bristle head has a novel bristle formation, with the bristle holes being formed into parallel horizontal lines, and the bristles taking on a rounded shape. The toothbrush is further provided with a novel calendar reminder mechanism in the form of a rotatable cap coupled to the distal end of the brush handle, allowing a user to set a month reminder for the next time the detachable bristle head should be replaced.