Do you need to see a dentist twice a year?

Dental professionals have long recommended a teeth cleaning every six months. One expert, Edmond R. Hewlett, a professor of dentistry at the University of California, Los Angeles, explains why a few people can get by with less frequent visits to the dentist, while others should consider going even more often.

The biannual dental visit was designed with the “average” person in mind, Dr. Hewlett says. That means people who are middle-aged, don’t smoke and who brush their teeth twice a day and don’t eat too many sweets. Within six months, the majority of people will produce enough tartar that it will need to be scraped off by a dental hygienist.

Some people may be fine going for longer periods between cleaning. But it’s a category of patient that might seem difficult to qualify for. Typically, these people are in their 20s and 30s who are otherwise healthy, eat extremely well and floss daily, Dr. Hewlett says. For the rest of us, whose dietary indulgences and dental hygiene aren’t so ideal, six months seem a safer bet.

A number of factors might make it a good idea to see a dentist three or even four times a year. People whose diet is rich in sugary foods or drinks should consider more frequent checkups, Dr. Hewlett says. And people who are older, or who have dry mouth, might be more prone to the damage bacteria can cause to teeth, gums and bones.

“As we get older, we start to accumulate more health conditions from the various problems we’ve had over a lifetime, so your risk status will change and usually go up,” says Dr. Hewlett. Dry mouth, which is a common side effect of many medications, means there is less saliva, which makes it easier for bacteria to grow.