Although I found several opinionated folks who said things like "of course, green tea stains less than black, because it is lighter", I couldn't find anyone with real experience to back this up. Except one guy, who started drinking more tea at the same time he started drinking black tea, so he blamed it on the black tea instead of on the sheer amount of tea.
A dentist on this site stated that he sees the same stains regardless of the tea color:
And this study summary concluded that hot green tea actually stained slightly more than regular hot tea (I assume he means black tea):
As for herbal "teas," like rooibos, they have their own unique reasons for staining, so of course they are going to vary widely
. This study showed that herbal teas stained teeth, but didn't specify which teas they tested, or how the results varied:
Some other sites:
http://teaswap.stefmike.org/teaswap_arc ... 01433.html
In general, the consensus seems to be that tea staining is less of a problem if you brush and get your teeth cleaned regularly. And, since tea contains flouride and can actually kill bacteria that cause tooth decay, it is considered to be - overall - beneficial to dental health.
To be more specific, the tips I've gotten have been:
1. Never drink tea immediately after brushing your teeth. It is best to either eat something first, or wait an hour.
2. Whenever possible, do brush your teeth after drinking tea.
3. Use a non-abrasive, whitening toothpaste.
4. Get your teeth cleaned every 6 months (that is how often you are supposed to get your teeth cleaned regardless).