According to the National Health and Nutrition Examination Survey, almost two-thirds of people with depression reported having a toothache in the last year — significantly higher than the population on average. What's more, half of all people with depression rated their teeth condition as fair or poor. A scientific review of related studies found a strong link between gum disease and mood conditions like stress, distress, anxiety, depression and loneliness.

The most obvious explanation for the link comes from the behavioral effects of stress, depression and anxiety. When you suffer from these conditions, you might lose focus on oral health habits, which can lead to significant dental issues. If you're depressed, for example, you're more likely to brush and floss at irregular intervals, skip dentist visits, eat an unhealthy diet and smoke.

Biologically, depression and anxiety cause several factors that impact oral health. The stress they create manifests itself in the body as a hormone called cortisol. As cortisol levels increase, the immune system gets weaker. This can leave you vulnerable to mouth conditions like gum inflammation (gingivitis) and gum disease (periodontitis). In addition, medications prescribed for depression and anxiety can cause dry mouth. This lack of saliva can mean that food debris, plaque and bacteria aren’t getting rinsed from teeth easily, which can make it easier for cavities to form.

Anxiety, in particular, tends to be associated with several oral health issues. If you have anxiety, you're more susceptible to canker sores, dry mouth and teeth grinding (bruxism). As with depression, these issues may be attributed to a lack of oral care or as side effects of anxiety medication.

Luckily, when depression or anxiety takes a toll on oral health, there are ways to fight back. The simplest step you can take to maintain your oral health is to brush twice a day and floss daily. Set a timer to remind you to brush and floss, and make an appointment with your dentist. He or she may recommend a nightguard to stop grinding, or prescription fluoride toothpaste for cavity prevention. And consider talking to your doctor or therapist about how stress reduction techniques or cognitive behavioral therapy can offer relief.