Wear the whitener for a shorter period of time until you get used to the process. Sensitivity to hot and cold is the most common side effect from using teeth whiteners. This sensitivity normally goes away after about 24 hours.
Use toothpaste especially formulated for sensitive teeth. Even toothpastes marketed for sensitivity now offer the option of a whitener.
Wear a fluoride gel in your tray for 4 minutes before and after whitening to help strengthen your teeth. If using trays to whiten your teeth, you may purchase a high concentration of fluoride by asking for it from your pharmacist.
Stop use of the whiteners for several days if the sensitivity continues.
Wipe off any excess gel after applying the tray by using a tissue or cotton swab. Sometimes the gel from trays can cause gum irritation.
Avoid lemon juice as a home remedy whitener. The juice removes calcium from your teeth which can damage the enamel on your teeth and cause decay.
Avoid brushing your teeth with smashed strawberries. They will whiten your teeth, but the high sugar and acid content can cause irreparable damage.
Read labels. Avoid any products with acids or abrasives. These can damage the enamel of your teeth.