Why is Sensodyne recommended & how long after professional teeth whitening procedure before you can return to using regular toothpaste, i.e. Tom's?

Sensitive teeth. Sensodyne helps decrease teeth sensitivity mainly to cold. Teeth whitening is thought to increase sensitivity in some cases. Your dentist suggested Sensodyne for this reason. If your teeth were not sensitive before the whitening then finish the tube and return to your regular tooth paste. Happy chewing!!
Only as recommended. Sensodyne should only be used as recommended by your dental professional. Unfortunately many people start using it when they experience sensitive teeth and have not seen a Dentist to determine the reason. They may have cavities causing the sensitivity which get larger if undetected or treated. Only if the Dentist finds no cavities and determines it is the whitening procedure should it be used.
Whitening. 80% of patients will experience sensitive teeth after whitening. The most common tooth-whitening ingredients are hydrogen peroxide and carbamide peroxide, which have been known to cause teeth whitening sensitivity as they penetrate the tooth enamel. If you have no sensitivity, it is fine to go right back to your regular toothpaste.