An old adage says an apple a day keeps the doctor away.

It may also brighten your smile.

Dr. John Heimke, of Rocky River, Ohio, says apples, carrots and pears are known to improve teeth whitening.

"By eating more nuts -- almonds for example -- or celery, stains and debris are moved off the tooth so the teeth become lighter," Heimke says.

Heimke says "teeth are degrees of yellow or gray." Nevertheless, when patients are asked what they would change about their smile, the most common answer is to have whiter teeth.

According to Oxyfresh, a leading oral hygiene product company, Americans spend about $1.4 billion annually on tooth-whitening products.

Mouth Chemistry

Other foods can also improve oral health by promoting a balance of bacteria and microorganisms in the mouth. Heimke says the right foods can be anti-inflammatory, alkalizing and antioxidant-rich -- factors he refers to as the three As of a healthy smile.

Other good foods for your mouth include blueberries and fish, which are high in antioxidants; green tea, which contains a catechin that kills bacteria that convert sugar to acid; kiwi, which is rich in vitamin C; and mushrooms, which have lentinan that prevents harmful bacteria on teeth.

Wasabi prevents the effects of harmful bacteria on the teeth, while water also works well to defend against harmful bacteria, he said.

Smile Makeovers Equal Confidence

Although teeth may not actually be white, many believe that improving one's smile improves self-confidence.

"It has been shown that people with a beautiful, natural white smile tend to do better in life and are healthier," Heimke says.

He adds that sometimes patients need more than whitening products for a smile makeover. The business includes everything from whitening to complex orthodontics, porcelain veneers and crowns.

"I had a patient who came in all depressed, barely could smile -- life was miserable," Heimke, who specializes in cosmetic dentistry, says. "He said people thought he was mean or an unhappy guy. He said, 'I'm nice and am happy, but nobody knows.'"

After getting veneers, his life changed.

"The next visit, he had a sparkle in his eye. People at work said, 'What have you done?' and he became the life of the office," Heimke says. "He did better in all aspects of life. We changed his life in a matter of a few hours."

Take Daily Care Of Teeth

Although the smile makeover business is rapidly growing, Dr. Garry Rayant, editor-in-chief of Dear Doctor - Dentistry and Oral Health says the old adage of brushing twice a day and flossing should not be forgotten. Dear Doctor also provides online advice to visitors.

"Use a soft microfine, multitufted toothbrush … the biggest mistake most people make is to use a stiff bristle brush and brush too hard and too frequently," Rayant says. "The key is to hold your toothbrush like a paintbrush, brush gently and aim right into the gum line. Use your tongue to make sure you've done a good job."

Like Heimke, Rayant believes that healthy eating and plenty of water helps oral hygiene. Rayant adds that people should avoid sodas, sports drinks and sugary beverages to maintain a bright smile.

"In addition to the sugar in these drinks, (they) very acidic. They literally dissolve the surface enamel, causing a condition called dental erosion," he says.

These drinks also contribute to the acidic level in the mouth.

"Just one drink per hour and your mouth is continually acid all day long, setting up the conditions for both tooth decay and dental erosion. (These drinks) will not brighten your smile or your day."

Rayant points out, however, that the beauty of a smile is in the eye of the beholder.

"If you think about what conjures up a perfect smile, it's a little different for everybody, and as pointed out before, a smile really is a lot more than pretty teeth," he says. "The concept of a perfect smile is really quite individual, although also cultural. 'Perfect smiles' are made up of eyes and hearts and all those other magical qualities that radiate from within."