Red wine is known to stain the teeth, but, surprisingly, white wine is also a culprit. Mark S. Wolff and colleagues from the New York University College of Dentistry soaked cow teeth in red wine, white wine, or water for one hour (which mimics the effects of sipping a drink throughout a meal), then exposed them to black tea.
Pretreatment with red wine caused the darkest stains, but the contact with white wine caused significantly darker stains than water. And white wine followed by tea resulted in stains almost as dark as those from red wine alone. The acids in white wine temporarily dissolve a microlayer of tooth—making the tooth rougher and more vulnerable to staining by coloured foods.
Orange and grapefruit juices, lemon, and colas may have a similar effect. It is advisable for wine drinkers to avoid brushing their teeth immediately after drinking (since teeth remain in a weakened state and prone to wear for about 20 to 30 minutes), to rinse with water instead, and to use a whitening toothpaste when they do brush.