(FORTUNE Magazine) – I have a mouth only a dentist could love. It contains a state-of-the-art ceramic bridge, porcelain crowns, the fanciest inlays, the priciest onlays--$24,076 of repairs and gear in just the past three years. As the daughter of a dentist, I know teeth. I knocked out my permanent central incisors at age eight. I broke my jaw, the right condial, at 29. Did I mention that titanium plates fasten my anterior choppers to my maxilla?

While I hope that your mouth is not the costly war zone mine has been (in three years, I've spent $12,613 out of pocket), you too need to invest to ensure that your teeth last all your life. "The baby-boom generation is the first to hold on to their teeth," says Dr. Frederick Eichmiller, director of the American Dental Association's Paffenbarger Research Center in Gaithersburg, Md. "Half the previous generation had dentures by their 60s. Thanks to fluoride and advances in technology, about a quarter of baby-boomers will."

Your gums, not your teeth, are your first line of defense. Seventy per cent of lost teeth have no cavities, according to Dr. Robert Pick, a Chicago periodontist and spokesman for the ADA. Gum disease afflicts four of five adults, he says, and attacks insidiously, eroding the bone and tissue that anchor your teeth. "It doesn't hurt, just like high blood pressure and high cholesterol don't hurt." Gum disease may even kill: Some researchers believe it stimulates plaque buildup in the arteries, increasing the risk of stroke and heart attack.

Keeping gums healthy involves flossing every day (no-brainer) and making sure your dentist, at every checkup, does a periodontal probe. He inserts a measuring device below your gum line; it's painless, but if the dentist can delve four millimeters or more, you may be in trouble. Surgery can stop, and sometimes even reverse, gum damage. One tooth-saving procedure involves cutting a flap in the gum and injecting regenerative gels to get the bone growing again. This can cost up to $8,000, but it can save precious teeth.

The biggest recent advance in dentistry is implants. Only a few years ago, to replace a missing tooth you would have had to settle for a crown and bridge--a false tooth that attaches to (and requires the dentist to cut down) adjacent living teeth. Implants, by contrast, fasten directly to the bone; they don't disturb neighboring teeth. Implants aren't for everyone; you need substantial bone to mount the new tooth. And they're expensive. Dr. Jonathan Levine, my fancy Fifth Avenue prosthodontist, quotes $5,000 per tooth for the package, including surgery--but this is no more than the amount he charges to replace a tooth with a three-unit bridge. "In the long run, implants save you time and money because you're not committing the adjacent teeth to future dental work," Levine says. And if you take proper care of your gums, implants should last 20 years-plus, at least as long as crowns.

There's even better technology in the pipeline. In the coming year, dentists will begin using "smart" fillings and cement to reverse tooth decay. These materials release calcium phosphate, which dissolves from the tooth as a cavity forms. "The restorative materials literally rebuild the tooth," says the ADA's Eichmiller. More is on the horizon, including controlled-release fluoride systems and compounds to repair deep cavities that currently would require require root canal. Depending how far technology takes us--and how far ethicists allow dentistry to go in areas like stem-cell research--eventually you may be able to get a tooth bud implanted to regenerate a missing tooth. That means teething could become a welcome part of midlife.

--PATRICIA SELLERS