The majority of people, 77 per cent, brush twice daily, which is a good sign.
Experts say you should replace your toothbrush every three months. And if you've been suffering with a cold or flu it's a good idea to replace your toothbrush.
It's also a good idea to keep your toothbrush away from anyone else's and clean it regularly, according to British dentist Dr Rhona Eskander.
"The mouth harbours literally hundreds of different types of micro-organisms, some of which can be transferred to a toothbrush during use," she said.
"Rinsing a toothbrush under running water from the tap does not remove all these germs."
Within just two days, toothbrushes can become heavily infected with disease-causing bacteria, viruses and fungi.
Sharing a toothbrush is not only unhygienic, it's also "gross" according to the Freshbrush study, with 50 per cent of people said they were grossed out by the idea of sharing their partner's toothbrush.