Dentists recommended that a toothbrush be kept at least how many feet from a toilet to avoid airborne particles?

The general advice appears to be to keep toothbrushes at least 6 feet away from toilets, so that bacteria from toilet activities (flushing releases bacteria into the air) is less likely to contaminate your brush.

Because most people store their brushes in the bathroom, it’s easy for them to become infested with fecal matter and other microbes you wouldn’t want in your mouth. If you’re keeping your toothbrush within six feet of a toilet, that’s too close, according to Curatola.

http://www.foxnews.com/health/2014/03/12/how-gross-is-your-toothbrush-5-toothbrush-hygiene-mistakes-youre-probably.html

That means I should keep mine in another room!

Most people should I suppose...there aren't many bathrooms, unless you're rich of course, where the toilet is more than 6 feet from the sink...which is in the general area of where people keep their toothbrush. I've always kept mine in the confines of the medicine cabinet when not brushing though...I hate the way toothbrushes look when they are displayed where they can be seen.

This might be of interest:

http://www.wikihow.com/Keep-a-Clean-Toothbrush

One should not worry too much about fecal contamination on a toothbrush. Think of all the no-so-sanitary things we do with our mouths in the name of pleasure.

We really look down the wrong roads concerning our own health.