Q. I have a sensitive tooth that seems to get more sensitive in cold weather. Does temperature affect teeth?

A. Temperature does affect teeth. A single tooth that is more sensitive than others should be looked at by the dentist. Sometimes the health of the tooth can cause a tooth to be more sensitive.

But there are several reasons a tooth could be sensitive. It would be best to have it checked by your dentist.

Q. I am 67 and not missing any teeth, but my teeth have shifted quite a bit and my bite is terrible. My dentist suggested a visit to an orthodontist to keep the problem from getting so bad that it affects my jaw.

Does this make sense for someone my age?

A. Many adults have orthodontic treatment and it may be right for you. It would be good to know why your teeth have shifted. For example, some dental problems can cause teeth to shift, such as gum disease.

To have orthodontics as an adult, it is important to be sure that dental disease such as gum disease and cavities are under control. So, a complete examination should be the first thing to consider.

Q. I want to get my kids and their families some kind of water pic or electronic tooth cleaning system for Christmas. Do you have any recommendations as to what works best? Thank you.

A. There are a variety of systems available in a wide range of prices. I would avoid ones that simply squirt water. Better choices are sonic toothbrushes.

Take a look at how the individual units operate and how easy they operate. Is there an automatic timer on the brush so that it shuts off in a reasonable time? Does it look easy to operate (or are there too many buttons to push).