These are the interior and exterior stains of the tooth enamel defined by a change in the colour or shine of your teeth.
Extrinsic stains typically result from a collection of individual behaviours like smoking, eating dark fruits (blackberries, blueberries), or drinking dark drinks like (red wine, coffee, or tea).  These stains vary widely because they are largely due to lifestyle habits and can be managed by whitening toothpastes as these stains reside on the surface of your teeth.  Some at-home methods may be effective with these stains but they can hurt your teeth which could be disastrous for your wedding day.  You may want to stop eating dark-pigmented foods and drinking sugary and darker drinks as well.
Intrinsic stains occur in your teeth within the tooth enamel due to a wide range of factors like genetic disorders or local factors during tooth development.  Intrinsic discolouration is also more common with aging as the enamel becomes thinner.  To remove these stains bleaching agents must be used, but the methods and effectiveness depend on the technique, type, and severity of the stain being addressed.  These types of stains will require help from the pro's which you can learn more about by clicking here: