There are two classes of dental stains. For intrinsic stain, the teeth's discoloration is caused from the "inside" by "internal" agents such tetracycline and fluoride. In contrast, in extrinsic stain, the teeth's discoloration is caused from the "outside" by "external" agents such as tea, coffee, and tobacco. Intrinsic stains are harder to remove than extrinsic stain. I recommend bonding and veneers treatment for intrinsic stains and bleaching for extrinsic stain.

By far the best and fastest bleaching solutions are offered by your dentist. During a typical whitening procedure, your dentist will fabricate a custom tray to hold whitening gel against your teeth. You take the trays home and wear the gel-filled trays each night or for several hours during the day for several weeks.

Dentists can also bleach teeth in the office. This is called power bleaching or laser bleaching. Both techniques work equally well and are offered both as a "jump start" prior to home whitening and as a separate "stand alone" procedure.

While you can get over-the-counter whitening kits, they usually aren't as effective as professional whitening procedures. Because the over-the-counter trays are not custom fitted, the whitening agent may leak out and irritate your gums. Want a whiter smile? Ask your dentist about dental whitening.

Besides, you need a dental evaluation prior to whitening your teeth for several reasons:

?The teeth to be safely bleached if it has no cavity on it.
?There are two type of stains on the teeth: extrinsic and intrinsic. Extrinsic staining is the stain on the teeth that comes from ther outside such as tea, coffee, and smoking. Intrisinc staining originates from the inside of your own body such as tetracycline and blood. The method and the recommendation to whiten your teeth differ for each situation.
?You will need someone to monitor your progress. Yes, there is such thing as OVER WHITENING!
?Most of the over-the-counter product will lighten your teeth a little at a higher risk of swallowing a lot of the bleaching chemical.
?To inrease the shelf-life, most of the over-the-counter whitening products are added with an acidic preservatives. The acid dissolves the precious enamel of the tooth and causes extreme tooth sensitivity. Professional products have no preservable; the only way to prolong the shelf life for the professional products is to refrigerate them.

The best way to whiten your teeth without hurting them is to see your dentist. The whitening toothpastes that are on the market are abrasive to your teeth and could cause damage to the enamel. The ADA (American Dental Association) has not approved any over-the-counter whitening products such as Crest White Strips. Therefore, I would not recommend such products for now.