Gleaming white teeth is considered to be synonymous with healthy teeth. In fact, in countries like the US, tooth whitening is reportedly one of the most commonly requested dental procedures.
As we are very used to seeing perfect white teeth beam out from cinema screens and magazines from all around the world, we tend to assume that white teeth are attractive and healthy.
However, according to a BBC report, the colour of our teeth is influenced by a number of factors. It can be based on our genes, age or smoking, eating and drinking habits and also on certain medications.
The yellow stains can be because of tomato-based sauces, coffee leaving behind coloured compounds called chromogens or such other things. On the other hand, bacteria or fungi can cause green, greyish, furry looking stains.
A number of studies have been previously been conducted in laboratory test tubes using cows' teeth or sometimes extracted human teeth, to find out about its health.
In one of the studies, conducted by Mark Wolff from New York University cows' teeth were soaked in black tea, red wine or white wine for an hour.
It was found that red wine left the strongest stains and surprisingly, black tea didn't stain the teeth unless it had been preceded by white wine.
Researchers believe that the acid content of the wine may have made the enamel slightly more porous and allowed the tea to leave the stain in the case of black tea.
Moreover, it was concluded that food and drink-based stains may discolour teeth, but that doesn't mean that they are unhealthy.
It's quite possible to have gum infections or cavities even having pearly white teeth. Similarly, one can have perfectly healthy teeth even when they are off-white, yellowish or even brownish.