9 Things Your Smile Can Tell You About Your Health

Flossing made headlines earlier this year when an Associated Press report claimed that research shows little evidence it's worth your while. But don't quit the habit just yet, says Wayne Aldredge, DMD, president of the American Academy of Periodontology. "All the studies they looked at were of short duration, some as little as two weeks. Gum disease is a process that takes years to develop."

Over time, the bacteria hiding between your chompers can build up, promoting acid production that erodes teeth and leads to cavities. Flossing does help get rid of those harmful bugs. The best way to do it: Slide the strand vertically, up and down the sides of your teeth (don't saw back and forth). If you really dislike flossing, try and interdental brush. Some research suggests that these wiry, cylindrical little brushes ay be even more effective than dental floss.

The time and effort you put into oral hygiene (including regular dental cleanings) may pay off in spades. Research suggests that the condition of your gums is connected to a variety of health issues: Several studies have found a link between gum disease and heart disease. (A 2015 Korean review discovered that folks who slacked off on brushing and flossing had higher rates of hypertension.) Other research suggests an association between oral health and premature birth, rheumatoid arthritis, Alzheimer's, and even lung cancer. One hypothesis is that gum disease triggers inflammation throughout the body, increasing a person's risk of illness.

If an upcoming dentist visit makes you nervous, you're not alone. For 1 in 10 people, the fear is so intense that they avoid going, according to research. "That really backfires, because people put it off for so long that they end up needing all sorts of painful procedures," says Mark Wolff, DDS, chair of the department of cariology and comprehensive care at the New York University College of Dentistry. Believe it or not, seeing a shrink can help: A 2015 study published in the British Dental Journal found that 79% of severely anxious patients who attended an average of five sessions with a cognitive behavioral therapist were able to undergo dental treatment without sedation.

Another option? Bring earphones. Listening to your own soothing music will help you relax, says Dr. Wolff. And make sure you tell your dentist you're nervous so she can work with you. "If they are not sympathetic," says Dr. Wolff, "you need to find another dentist."

While over-the-counter lip plumpers can give you that trendy bee-stung look, it'll fade after just a few hours. If you want your fuller lips to last longer, ask your derm about hyaluronic acid fillers. The injections, which are relatively painless with a little numbing cream, take about 10 minutes, and the effects last at least six months, says Bruce Robinson, MD, a dermatologist in New York city. Unlike collagen, formerly the go-to dermal filler, hyaluronic acid creates subtle, natural-looking results. The cost can range from $500 to $2,000, depending on where you live.

If you get fever blisters on your lips, they may be more likely to make an appearance this time of year. You can blame stress (ubiquitous during the holidays), chapped lips (any trauma to your kisser can trigger an outbreak of cold sores, which are caused by the herpes simplex virus), or a weakened immune system during wintertime, says Dr. Robinson.

As soon as you feel that familiar tingling or burning sensation that often begins a day or two before a cold sore forms, call your doctor. She can prescribe acyclovir, an antiviral medication that can cut the healing time in half. Dr. Robinson also recommends Domeboro, an over-the-counter soothing soak that you apply twice a day to help dry up the blisters.

A genuine smile can be a powerful thing. For example, in one 2014 study, seniors who watched a funny video for 20 minutes performed better on memory tests afterward than a control group who simply sat calmly for the same length of time. Smiling is the first step toward laughter, and it seems to prompt an increase in endorphins and dopamine in your brain, which provide a sense of pleasure and reward, explains Lee Berk, DrPH, a preventative care specialist at Loma Linda University and one of the authors of the study. "But the expression must be authentic," he points out. Takeaway tip: Next time you have a stressful event, prep by Googling that dancing-kitty video that never fails to make you grin.

You've probably heard the advice "Put on a happy face" when it's the last thing you feel like doing. Well, you can relax those cheeks, because some research shows that forcing a grin isn't actually a good idea: A 2011 study found that people who faked a smile all day felt less engaged in their work than people who sported genuine ones.

"When you fake a smile, it creates a feeling of tension or dissonance that is unpleasant to experience," explains study author Brent Scott, PhD, a professor at the Eli Broad College of Business at Michigan State University. "In other words, people do not like to feel like a fake." Scott's solution: Summon a natural happy expression by visualizing yourself doing something you love.

Surprise, these foods and drinks can harm your teeth.

Wine: You know the red stuff can stain, but all vino is acidic, which means it can erode your enamel, leaving teeth more susceptible to staining and sensitivity, says Dr. Aldredge.

Diet soda: It's just as hard on your teeth as regular soda, according to a 2015 Australian study. These drinks often contain phosphoric and citric acids, which can strip away enamel.

Dried fruit: It's sticky and high in sugar, which translates to cavities, says Dr. Aldredge. The best option: raisins, because they suppress the growth of some mouth bacteria, says research.

Ice: Chewing on hard substances can damage enamel, per the American Dental Association. For the sake of your teeth, cool off with a tall glass of ice water instead.

Mashed potatoes: Foods filled with starch stick to your teeth, says Dr. Aldredge. Potato chips, which tend to get trapped in your teeth, aren't great either. Try to floss after you eat to remove food particles.