Reports The Wall Street Journal:
Dr. Howell recommends replacing the brush every three to four months as a guideline. "I like to mark my new brushes with a date," she says. On the flip side, if your brush isn't looking used in four months, you may not be brushing long enough. Two minutes is the recommended time for a thorough cleaning and for fluoride uptake by enamel. Children, who seem to abuse these oral tools, may need their brushes changed more frequently.
To read more, visit The Wall Street Journal.