Q. I'd like to have whiter teeth. But no matter what I try, including whitening toothpaste and other drugstore treatments, I can't get the brightness I want. Can professional treatments help?
A. There are many myths and misconceptions when it comes to our teeth. One of the most common is that all stains and discolorations can be easily whitened or cleaned away. Sometimes they can, but it depends on what's causing your tooth discoloration. Sometimes even professional procedures can't make your teeth sparkling white.
Some stains do respond to cleaning and whitening procedures. For example, the brown or yellow stains caused by tobacco, coffee and some foods can usually be removed by a trip to the dentist for a cleaning.
It may surprise you to know that some metals can change your tooth color if you inhale or swallow them. Copper can turn your teeth green, while mercury can turn them black. I had a patient once who put copper pennies in the water when she put flowers in a vase. The copper kept the water from clouding up. One day she accidentally swallowed the water in the vase -- don't ask me why; I was too amazed to ask her.
These types of stains usually respond well to professional cleaning or tooth-whitening procedures, as they did in her case.
Tooth discoloration related to damage or death of the pulp is harder to fix, but not impossible. The pulp is the soft, inner part of your tooth that contains blood vessels and nerves. When it is damaged or killed, the tooth looks darker. Lightening the pulp with bleach can whiten the tooth's appearance.
Certain childhood events can cause hard-to-treat stains and discoloration of the teeth. Taking the antibiotic tetracycline in childhood can cause stains that are hard or impossible to whiten away. And children raised drinking water that has an excess of certain minerals in it (such as copper or silver) can have unevenly colored teeth.
Even stains like these that don't respond well to whitening or cleaning can sometimes be masked by bonding. In this procedure, the dentist paints a plastic-like material onto the tooth, which whitens it.
It's important for you to know that, ironically, too much tooth whitening can make your teeth look gray. The whitening procedures can make the teeth translucent, instead of opaque white. That's one of the many reasons you should see your dentist before taking any drastic steps to whiten your teeth. Using whitening toothpaste regularly is fine, not drastic. But check with your dentist before doing more than that.
We have a lot of information about dental health in our Special Health Report, "Dental Health for Adults: A Guide to Protecting Your Teeth and Gums." You can learn about it at my website.
• Dr. Komaroff is a physician and professor at Harvard Medical School. Go to his website to send questions and get information: AskDoctorK.com.