October 1, 2015 | Caffaratti Dental Group Replacing my toothbrush when I visit the dentist every six months is adequate. TRICK. A worn out toothbrush won’t do much good in keeping your oral health up to par. When the bristles become flat, frayed or broken down, they don’t clean as well. Instead, change your toothbrush every three to four months, or at the beginning of every season. Fall just began, so now is a perfect time for you, and every member of your family, to pick out a new toothbrush. If you’ve been using a toothbrush for three months and it still looks new, you’re not brushing long enough or often enough.