A recent study by New York University dental researchers has found that drinking white wine can increase the potential for teeth to take on dark stains. The researchers compared two sets of six cow teeth, whose surface closely resembles that of human teeth, and used a spectrophotometer, an instrument that measures colour intensities, to evaluate staining levels.

They found that teeth soaked for one hour in white wine before being immersed in black tea had significantly darker stains than teeth immersed for one hour in water before exposure to the tea.

'Dipping teeth in white wine for one hour is similar to the effect of sipping the wine with dinner. The acids in wine create rough spots and grooves that enable chemicals in other beverages that cause staining, such as coffee and tea, to penetrate deeper into the tooth,' said Dr Mark Wolff, Professor and Chairman of the Department of Cariology & Comprehensive Care at New York University College of Dentistry. Professor Wolff oversaw the study, which was led by Ms Cristina M Dobrescu, a third-year student.

However, when the researchers repeated the experiment with red wine, the resulting stains were significantly darker than those in the white wine group, as red wine contains a highly-pigmented substance known as chromogen. The findings were presented at the annual meeting of the International Association for Dental Research in Miami, Florida.