When bleaching one’s teeth, it must be kept in mind that the bleaching process will not effect the color of dental restorations such as tooth-colored fillings, bonding, or porcelain laminate veneers or crowns. It will not harm porcelain, but scanning electron microscope studies have shown some some minor pitting in composite (tooth-colored) restorations. Hypocalcified and fluorosed areas have stark white splotches. When initially bleaching the teeth, these areas tend to stand out dramatically, however, as time goes on, the surrounding tooth structure will begin to lighten, thus allowing the hypocalcification to blend in better. Teeth bleaching will not remove these splotchy areas, just make them less noticeable. Many people have grey stains in their teeth. These stains can be very resistant to the bleaching process. The products that cause the grey color do not appear to oxidize as well. On the other hand, yellow stains are very amenable to bleaching and will lighten very well. The nice thing about the grey stain is that it is not as noticeable from a conversational distance as the yellow, so the teeth can still have a light, appealing appearance even with some residual grey.