Some may find that teeth whitening cause their teeth to ache and become sensitive to extreme temperatures. This is because many professional and At-Home teeth whitening kits use certain ingredients that can cause sensitivity for some. It is often most noticeable with extreme hot and cold food or beverages. It can also cause an achy feeling during the whitening process. Opalescence products, however, include desensitizing ingredients that provide additional comfort by reducing sensitivity. Thankfully, any sensitivity that starts with teeth whitening is typically short-term and resolves with time.