After soaking them in white wine for an hour, then soaking them in black tea, the teeth were significantly more stained than those put in water first.
Researchers say the acids in wine create grooves that allow chemicals in other dark drinks to penetrate deeper into the tooth.
Source: SEAU 13 News
Shawn Watson, writes:
In fact, according to this press release, the study has also determined that red wine is by far the beverage that people whitening their teeth should fear most when comparing one stain causing beverages to another, as it contains a highly pigmented substance called chromogen.
If forgoing wine of any creed is out of the question during your whitening sessions, it might me worth considering brushing your teeth immediately after consumption, or rinsing with water or your preferred mouth rinse. If you are in a situation where brushing your teeth is a "faux pas" sip water along with your wine to dilute any stain causing pigments and to flush away any acids eroding the surface of your tooth.
So it looks like wine doesn't quite stain teeth directly itself, but rather prepares teeth to be stained by other substances. This actually seems worse to me than wine staining teeth directly — if wine is actually damaging the teeth physically, then it's not just things you eat or drink immediately thereafter which will create stains. Presumably, there is an increased chance for stains for quite a while afterwards.
Of course, people don't sit with wine in their mouths for an hour, do they? I haven't seen anything which indicates that wine will create grooves in teeth after a short exposure, but this still may be relevant to people who drink a lot of wine over a lot of years. Whitening agents may counteract the effects of what ends up staining your teeth, but is there anything that would counteract the effects of grooves being created in your teeth?