tooth bleaching Over time teeth can become stained and discolored. This is due to a number of causes, the most common being aging, drinking tea, coffee some fizzy drinks and of course smoking! The act of bleeching is achieved though a process that lightens the discolorations on the tooth enamel. The system uses a strong solution placed directly onto your teeth.  A rubber dam is placed over your teeth to protect the gums. A bleaching solution is placed on the teeth and a laser is used to generate a small amount of heat. This is directed at the teeth. Oxygen from the solution enters the enamel and bleaches the teeth. The process lasts about 1 hour and results can normally be seen straight away. Although almost everyone can get some benefit from tooth whitening it's important to not that there are some instances where treatment may not be as effective. Your dentist will give you a thorough examination to determine if you are a good candidate for tooth whitening. Ideally your teeth need to be  in good condition with few or no fillings. Possible Side Effects. Some people experience increased tooth sensitivity to cold during treatment. Others report discomfort, in the gums or in some cases a sore throat. These symptoms normally disappear within 1-3 days after stopping or completion of treatment. There may also be small white patches at the gum line. Previous white fillings in front teeth may need to be redone. Crowns ( or caps) and denture teeth do not bleach.  How long do the results last Some patients may need periodic re-whitening. For best results periodic home whitening is reccomended.