Is there any evidence that this statement has any basis in reality or is it like when people do a 'cleanse' to get rid of the 'toxins' in the body?
Overall, the use of essential oils for cleaning is ideal. My ex-wife had horrible acne, and tried the harsh 'cures' like Proactiv. The fix was a simple blend of lavender and tea tree essential oils mixed with distilled water in a spray. Using that once or twice a day cleared her up within a week.
Disclosure: I own a small soap company and only use my own bars! :) [1]
When I grow out facial hair, there's a particular spot on my upper lip that starts to flake, which I also think of as "dandruff". Kept shaven, it's asymptomatic.
Basically, there seem to be many mysterious causes and effects involved.
We moved to various places -- Philadelphia, Shanghai, Costa Rica, Brazil. I can only really speak for Shanghai, which is incredibly hot with about 100% humidity in the summer (I have seen water pool on the floor of my building, just because there was so much in the air) and 1-4 degrees centigrade in the winter. I've never thought of it as misty.
Don't move to Shanghai for the weather.
I personally had HUGE successes with it in improving my overall hygiene - but be warned that it takes upto six months for your body to "reboot". during that time, your hygiene grows worse - before getting extremely better. I suspect it is the same case with the brushing thing : it will take quite some time before the flora and fauna of your mouth reboots.
[1] http://freetheanimal.com/2010/12/a-most-successful-self-expe... [2] http://paleohacks.com/questions/17060/no-poo-and-dandruff.ht...