Ask the Teeth Expert All your teeth questions, answered Interviewer: Brittany Risher

Expert: Lana Rozenberg, D.D.S., a cosmetic dentist in New York City (rozenbergdds.com)

I brush and floss regularly, but I still have bad breath all day, and all the mouthwashes I’ve tried stain my teeth. What can I do to make my breath smell better? —Ted
Lana Rozenberg: Mouthwash may mask your breath for a short period of time, but you’re not getting to root of problem. Mouthwash kills bacteria, but bacteria breed quickly—in couple of hours, you’re back where you started. The fact is, no matter how much you brush, you have to brush your tongue. Bacteria love to live in the crannies of your tongue. While there are many tongue brushes, all you need to do the job is toothpaste and a toothbrush.

Halitosis comes from something living in your mouth, so if brushing your tongue doesn’t work, you may have a cavity, a broken filling, or an infection. Check with your dentist. If he or she doesn’t find anything, it’s likely an internal problem, such as acid reflux, so see your physician.

There are so many toothpastes out there—what do I really need to look for when selecting one? —Keith
LR: Basically all the elements in toothpastes are the same, so look for one that encompasses all the things you’re interested in. Of course you want your toothpaste to prevent cavities, gingivitis, and plaque buildup, and most people nowadays want whitening toothpaste. The ingredients to look for are fluoride (fights cavities), triclosan (fights gingivitis and reduces plaque), and hydrated silica (whitens). I like Crest Pro-Health ($5, crest.com). It’s personal preference if you want one for sensitive teeth or anything else.

Electric toothbrushes are expensive. Is buying one worth the cost? —Aaron
LR: If you’re doing good job with a manual toothbrush, no. Rotary electric toothbrushes mimic the proper motion of brushing, that is, little circles, not back and forth, which can cause gum recession. Rotary brushes also have a timer to let you know when you’re finished—after 2 minutes, not the 30 seconds most people spend brushing.

Sonicare brushes are based on the principle of oscillation and vibrate many times per second to break up tartar. They work wonderfully, but not everyone can tolerate the high-pitched sound it makes. People with any bonded restorations should not use Sonicare because over time, the vibration will break down the cement in those fillings.

How can I tell if my gums are receding too much? —Isaac
LR: When you smile, if you see a root—which is a darker yellow than your tooth—you need to see your dentist. Also, if your teeth are sensitive to cold or brushing, then your gums are likely receding. Some recession is OK, but you don’t want to lose too much tissue because then it becomes a functional problem and you could lose the tooth.

My gums bleed when I floss. Does that mean I should worry about my heart health? —Jim
LR: No, but you should talk to your dentist. If you’ve just started flossing, your gums will bleed a little until they are conditioned to it—just like your muscles are sore when you first start an exercise program. Over time, your gums become tougher.

But if you’ve been flossing regularly and are seeing bleeding, there is an underlying issue. There are numerous possible explanations, including gingivitis and a poorly fitted crown that is impinging on your gum. See your dentist.

Do any chewing gums with teeth whiteners really work? —Peter
LR: No. The way whitening works is that the bleach is in contact with your tooth and it removes stains by oxidation. Chewing gum doesn’t contact the outside of your tooth. It stimulates salivary flow, which will remove staining bacteria off of the chewing surfaces of your teeth and some food particles. If you want to brighten your smile, you need to use a whitening agent that stays on the outside of your teeth for a length of time. I recommend Crest Whitestrips ($25, crest.com).

Can you make your gums recede by flossing too much or too vigorously? —A.J.
LR: Gum recession occurs on the outside or tongue side of your teeth; flossing is between them. If you press too hard, you can rip your gums or cause a tear, but you can’t make them recede.

Go to the next page for more teeth advice . . .