It is everyone's desire to look good all the time. A great smile will undoubtedly contribute to that, and we cannot avoid smiles at all times. When you have yellow teeth, it may not be so pleasing to offer smiles to everyone you comes across. Therefore a discolored smile can be undesirable to look at, and at times you may not get the same smile. This condition can make you lose your confidence and become irritated by your smile. This may even prompt someone to keep on hiding his/her teeth. And this might not be possible a hundred percent, and that is why we should know what causes yellow teeth so that we do not fall into that category.