I have bleaching trays from my former dentist and I do periodic touchups. I only do them once a year about a week or two after I get my teeth cleaned. I usually only need to do it one or two nights and I’m good untilthe next year. My husband told me that he read about some people who had problems from bleaching overnight. Is this really a danger? – Haley T.

Haley – The amount of time you leave the bleaching gel on your teeth depends on your individual sensitivity. If the bleaching gel isn’t creating sensitivity, you can leave the trays on.

While you sleep, your saliva production is reduced, and the bleaching gel stays on your teeth much longer and is more effective. Some people who wear the trays overnight experience a lot of sensitivity. In this case, a lower-strength bleaching gel can be used, or the trays can be worn only during the day for a limited period of time.

Anyone who has reason for concern about teeth whitening touch-ups—the gel, or the length of time it’s used—should speak with his or her dentist about it. Your dentist can examine your teeth and let you know if your tooth roots or the enamel of your teeth are being adversely affected.

This post is sponsored by Lowell dentist Dr. Michael Szarek.