Other factors which could easily get through the enamel to the dentin are cracks in the teeth suffered through a trauma to the tooth, grinding, aging and other accidents. Blood leeching inside the tooth will also tend to stay there and form a stain. While extrinsic stains are easier to remove, intrinsic stains usually needs more involved professional supervision. Since carbamide peroxide is only half the strength of hydrogen peroxide, the visible effect will take about two weeks of continued use, much longer than bleaching trays that contains hydrogen peroxide and in-office treatments but because it is, teeth whitening strips is gentle and comfortable to even those with very sensitive teeth and gums. Immediately afterwards, the teeth will be several points lighter than its natural color. This is to be expected as a result partly of teeth dehydration. The real color will emerge though after a few days. When the desired results are not achieved with the session, a follow up treatment will be recommended by the dentist to be scheduled at a future date. The reason for this may lie in the amount of time that the water enriched with peroxide is in contact with the teeth. For the rinse, the peroxide is in contact with the teeth for 2 minutes a day. Contrast this with the contact that happens with the teeth and the peroxide for strips, where the strips need to be attached to the teeth for as much as 30 minutes! Since majority of the sessions for laser technology will be made just for a single visit, then this will definitely serve as good news for the person with the sensitive teeth. Prepare for the costs If this is the kind of procedure that you would want to take for your problematic teeth, then make sure that you are ready to face the costs. Peroxides when it gets in contact with the soft tissues inside the mouth will often give a tingling sensation that may not be pleasant to about half of the patients undergoing teeth whitening. Peroxides also have a taste that may be unpleasant to some. In any case though the taste is very bearable and the tingling sensation may be ticklish but the feeling is always a cleaner mouth afterwards.