Dear Doctor: If there's no proof that flossing is beneficial, do I really need to do it?

Dear Reader: You're referring to an article published by The Associated Press last summer, which revealed that the studies cited by the American Dental Association (ADA) and the American Academy of Periodontology to recommend daily flossing are scientifically inadequate. To say the story caused a ruckus is an understatement.

According to the AP investigation, the advice to floss daily is based on studies that are "very unreliable" and whose quality is "very low." Many of the studies were funded by dental floss companies, which opened up "a moderate to large potential for bias."

It's important to note, though, that while the AP story found fault with the research, it didn't offer evidence that flossing doesn't work. So while you could use the revelations as an excuse to ditch the dental floss, dentists and dental hygienists say that manually cleaning the space between your teeth is still a good idea.

Their reasoning? Each tooth has five surfaces. Three of these -- front, back and biting edge -- can be cleaned with a toothbrush. However, the sides of your teeth, which sit adjacent to other teeth and can capture food particles and bacteria, require a different tool for removing both plaque and debris.

Dental plaque, a clear film, is actually a mass of hundreds of different acid-producing bacteria that naturally form in the mouth throughout the day. When left undisturbed, plaque can give rise to cavities and gum disease. The only way to get rid of plaque is manually. That means brushing and, for the inner surfaces of your teeth, flossing.

Matthew Messina, DDS, a spokesman for the ADA, concedes that the existing research on the benefits of flossing is less than rigorous. When flossing is done properly, however, Messina says it remains the most effective way to remove damaging plaque from those hard-to-reach inner surfaces of your teeth.

If flossing is painful, then you're probably doing it wrong. Rather than a sawing motion at the gum line, proper flossing is a gentle, vertical sweep along the inner edge of each tooth. Messina recommends that you ask your dentist or dental hygienist to demonstrate proper flossing technique.

For optimal dental health, the ADA recommends brushing with a fluorinated toothpaste at least every morning and evening, and visiting a dentist for professional cleaning twice a year. Considering how little time it takes and what's at stake, dental professionals agree that flossing should continue to be part of your daily personal hygiene.

(Eve Glazier, M.D., MBA, is an internist and assistant professor of medicine at UCLA Health. Elizabeth Ko, M.D., is an internist and primary care physician at UCLA Health.)

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o Media Relations, UCLA Health, 924 Westwood Blvd., Suite 350, Los Angeles, CA, 90095.)

Dear Doctor: My daughter had the chickenpox vaccine as a child, so she never had chickenpox. She's now an adult. Should she get a booster?

Dear Reader: That's an excellent question. The chickenpox (Varicella) vaccination has been widely used in the United States since 1996. Given in a two-dose schedule at 12 to 15 months and at 4 to 6 years, the vaccine has significantly reduced the incidence of chickenpox among the population. If your child had the vaccine 20 years ago, she is indeed still protected from getting chickenpox.

But -- and this is concerning -- she's less protected than when she got the vaccination. That's especially important because contracting chickenpox as an adult can lead to an increased risk of pneumonia and even death.

Children in some pockets of the United States are less likely to have been vaccinated, and thus outbreaks of chickenpox occur. This is also true for other countries with more spotty vaccination rates than the U.S. A 21-year-old may be more susceptible to getting the virus if he or she visits those areas.

The good news is that, in most areas of this country and the developed world, the vaccine has significantly reduced the circulation of the chickenpox virus in the population, so your daughter will be less likely to be exposed to it. And you can take solace in the fact that, if your daughter does develop chickenpox, it probably won't be as severe as someone who was never vaccinated. That's because she does have some immunity from her previous vaccination, so she will be less likely to get the severe complications that can occur in adults.

That said, there are many unknowns regarding what will occur later in life when your daughter is in, say, her 50s and her immunity to the virus has waned further. Currently, neither the federal Centers for Disease Control and Prevention nor the American Academy of Pediatrics recommends a chickenpox booster. That could change over time -- especially for those people traveling to areas where chickenpox is prevalent.

We will understand more about the vaccine and its protective powers as this first generation of people who received the vaccine gets older -- and as doctors and patients ask these important questions.

(Robert Ashley, M.D., is an internist and assistant professor of medicine at the University of California, Los Angeles.)

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o Media Relations, UCLA Health, 924 Westwood Blvd., Suite 350, Los Angeles, CA, 90095.)

Dear Doctor: My father passed away six months ago, and ever since, my elderly mother has withdrawn from all social activity. I can't help wondering if this poses a problem for her mental health.

Dear Reader: The loss of a loved one is a heavy burden for anyone to bear. For an elderly person, particularly a surviving spouse, it can be even more difficult. Elderly women and men are already dealing with challenges such as declining health, loss of independence and the shrinking of their longtime social circles. When faced with the loss of their life partner, the overwhelming grief can cause them to retreat.

Your concern for your mother is well-founded. Research shows that social isolation poses a real threat not just to her cognitive function, but to her physical health as well.

Elderly people who are socially withdrawn are at greater risk of long-term illness, high blood pressure, heart disease, dementia, losing their ability to walk and stay mobile, and of serious depression. Grief can suppress the immune system, making the elderly even more vulnerable.

Studies reveal that elderly men and women who do not engage with other people die at a significantly higher rate than those who remain socially connected. This is a particularly troubling statistic as the number of senior citizens who live alone is on the rise.

Fortunately, there are steps you can take to help:

-- Research shows that grief counseling can help surviving spouses manage their sense of loss. Encourage your mother so see a counselor, or find a support group that she can join.

-- Something as simple as making transportation easily available can help isolated seniors break free of their bubble.

-- If your mother has connections to a church or other spiritual community, reviving those ties can be helpful at this time.

-- Gathering family members at your mother's home for a meal or a movie can brighten her day. Make it a weekly or monthly habit if you can.

-- For seniors who are strong enough, volunteer work, particularly with young people, gives them a meaningful activity that often has a positive effect.

-- Encourage your mother to establish a new daily routine. A sense of stability can help life to feel normal again.

You may be so concerned about your mother's pain that you are shielding her from your own. Don't be afraid to let her see the sorrow you feel about your father's passing. Grieving together -- sharing memories, telling stories, simply stating how you feel -- can bring you closer and help her to feel ready to join the world again.

(Eve Glazier, M.D., MBA, is an internist and assistant professor of medicine at UCLA Health. Elizabeth Ko, M.D., is an internist and primary care physician at UCLA Health.)