The shade of our teeth depends on the thickness of the outer tooth layer that is enamel as well as various extrinsic or intrinsic stains. Teeth may look naturally yellowish in fair skinned individuals than in dark skinned. So many factors play a role in the color and shade of the teeth. If ur teeth color is yellowish, it is important to decide whether that color is natural or acquired in ur case. Then treatment should be planned accordingly such as Bleaching/ Veneers/ Crowns etc
Hi. I am not sure what you mean by "everything", but I am assuming you mean the whitening toothpastes commonly available. They do not whiten teeth significantly but are good for cleaning external discolourations. If you feel your teeth are yellow in colour, you can opt for either tooth whitening treatments or dental veneers. Tooth whitening treatments whiten your teeth from within, and depending on the type of whitening you choose will take from 1 day to 1 month usually. Their effect lasts for 6 months to 1 year, following which a touch up maybe required. With dental laminates or veneers, you can actually choose which shade of white you want your teeth to be. They can be made of resin materials or ceramics. The former work out less than tooth whitening treatments cost wise, but may stain over time. Ceramic veneers are costlier but the most permanent solution of all.