Your toothbrush contains what?!?!
This is gross, man! Why would you NOT replace your brush heads every month!
"They found that the brushes held on to between seven to 12.5 full doses of triclosan" and "brushes captured significant amounts of other chemicals commonly found in toothpaste including methyl salicylate, anethole, and butylated hydroxytoluene (BHT), an antioxidant used in some whitening toothpastes that has raised eyebrows based on its role as a possible carcinogen in animal studies."