Teeth will always stain. Even prosthetic teeth can stain extrinsically over time.
Tooth enamel is susceptible to staining due very much to its porous nature. Essentially, coloured foods and beverages are absorbed by your teeth on a daily basis and stains become ingrained that can lead to a darkening of the tooth. Food colour is not the only cause of staining; acidity levels in food can also make a difference in your tooth colour. Foods and beverages with high acidity levels, even ones that are not brightly coloured, endorse stains by wearing away at the enamel and temporarily softening the teeth, making them more prone to staining. This can be seen in our blog study where it is shown that orange juice has a significant impact on the enamel of your teeth compared with the insignificant impact from laser teeth whitening on your enamel. https://www.whitesmileclinic.ie/blog/2014/03/07/interesting-study-teeth-whitening-harmless-on-enamel,-orange-juice-harmful-to-enamel/
Food and beverage colour comes from chromo gens, or intensely pigmented molecules that easily adhere to dental enamel. A faction of food compounds known as tannins (found in coffee, tea, red wine, pomegranate, citrus fruits, smoked foods and legumes to name a few) enhance staining potential by boosting the chromo gens ability to stick to enamel. Maybe it could be considered this way: if a particular food or beverage can stain a white t shirt, then it will more than likely taint your teeth too, and certainly these foods and beverages will stain through regular consumption over longer periods of time if consistent oral hygiene (particularly brushing and flossing) is not adhered to.
When you drink hot or cold drinks the teeth contract, which allows staining to easily penetrate the enamel too.
Laser teeth whitening can help to counteract and remove staining intrinsically and extrinsically from the teeth; however, teeth will stain over time again. It is important to use a teeth whitening take home kit to help maintain the shade achieved after the in clinic laser teeth whitening and to top up when noticeable staining is occurring again. It must be noted that any heavy coloured foods or beverages should not be consumed for 24 hours after a laser teeth whitening treatment.