Pop quiz: Who’s taken a selfie? A better question: who hasn’t taken a selfie? A recent estimate says we take 93 million selfies worldwide every day. Narcissism? Perhaps. But the real danger seems to lie in selfie-induced injuries, and even death. People (mostly young adults) have fallen off bridges and cliffs, slipped down stairs, been bitten by rattlesnakes, mauled by bears, been hit by trains, shot themselves, and even been blown up by hand grenades. (We’re not sure how that happened, either.) Still, what we rarely hear about is that selfies—at least, certain types of selfies—may improve or even save lives. Take oral health. We all know that brushing and flossing can help prevent tooth decay, gum disease, and bad breath. And dental professionals have probably given us lessons in proper brushing. But when was the last time someone watched you brush and critiqued your form? Probably not since you were 6 years old. And that’s a problem, according to Lance T. Vernon, an instructor at the Case Western Reserve University School of Dental Medicine. “Often, tooth-brushing is learned and practiced without proper supervision,” he said in a press release. “Changing tooth brushing behaviors—which are ingrained habits tied to muscle memory—can take a lot of time and guidance.” To figure out how best to change these habits, Vernon and his colleagues did a study. First, they trained participants in proper brushing techniques. Then, at home, the participants put their phones on stands and took selfie videos of themselves brushing their teeth. The result? Although the study’s participants didn’t spend any more time brushing, they increased the number of brushstrokes, and those strokes were more accurate. Overall tooth-brushing skills (which included holding the brush at a 45-degree angle and making circular brushstrokes) improved eight percent. The lesson: Apparently, recording themselves as they brush makes people more conscious of their technique and can help eliminate harmful habits, according to Vernon and his team. Now he’d like to see apps where patients can get feedback and coaching from a dentist. Vernon’s not the only pro-selfie medical professional. Many dermatologists, for example, have patients e-mail photos of their moles, freckles, and other suspicious blemishes. These selfies can provide doctors with information that can allow them to rule out problems or take immediate action that could save a life. Selfies may also help doctors monitor their patients’ progress and the effectiveness of treatments and medication. Selfies can also help in those annoying situations where we have some kind of medical issue that mysteriously disappears in the doctor’s exam room, but just as mysteriously re-appears as soon as we get home. Kara Burns, a researchers at Queensland University of Technology in Australia, talks about the case of a woman who’d visited her doctor after an episode of slurred speech and facial paralysis. The doctor ran tests, which came back negative, and sent the woman home. When the symptoms returned, she captured it on video and sent it to her doctor, who immediately diagnosed a stroke. While some people worry that patients’ selfies will overload medical practices, others suggest that the net effect will be quite the opposite. If a doctor is able to accurately determine that a particular mole, for example, is nothing to worry about, the patient can stay home and the doctor can spend more time with another patient who truly needs treatment. Selfies can also be invaluable to patients who have mobility issues and would have significant difficulties making an office visit. Of course, there’s no substitute for seeing your doctor face to face. But there are plenty of times when an office visit is a waste of everyone’s time and resources. In those cases, a little selfie narcissism can go a long way.