Yes, flossing once a day is beneficial for your oral health, and it’s the frequency recommended by the American Dental Association. Daily flossing removes food particles and plaque from between your teeth, areas your toothbrush can’t reach. Only about 32% of U.S. adults actually floss every day, which helps explain why gum disease remains so common.
What Daily Flossing Does to Plaque
Plaque is a sticky film of bacteria that builds up on and between your teeth throughout the day. These bacteria embed themselves in a protective matrix that clings to tooth surfaces, especially in the tight spaces between teeth where bristles can’t fit. Left undisturbed, this biofilm hardens into tarite (calcite), causes cavities by breaking down tooth enamel, and triggers the gum inflammation that leads to periodontal disease.
Brushing alone handles the outer surfaces of your teeth reasonably well, but the gaps between teeth are a different story. Flossing physically scrapes this bacterial film off the sides of each tooth and just below the gumline, disrupting the colony before it can mature and cause damage. The key word is “disrupting.” Plaque reforms within hours, which is why doing this daily matters. Skipping a few days gives that biofilm enough time to harden and become much harder to remove at home.
How Much Does It Actually Help?
A major Cochrane review, the gold standard for evaluating medical evidence, found that adding flossing to brushing produces a statistically significant reduction in gum inflammation compared to brushing alone. The benefit increases over time: at one month, the improvement is modest, but by six months of consistent daily flossing, the reduction in gingivitis scores roughly doubles compared to the one-month mark.
The evidence for plaque reduction is less dramatic. The same review described the data as “weak” and “very unreliable” when it comes to measurable plaque removal at one to three months. That sounds discouraging, but context matters: the studies relied on participants flossing correctly and consistently, which is notoriously hard to verify. In clinical settings where technique is supervised, results tend to be better. The gingivitis reduction alone, which was more reliably measured, confirms that flossing is doing something meaningful below the gumline even when surface plaque scores don’t shift dramatically.
The Connection to Heart Disease and Other Conditions
Keeping your gums healthy isn’t just about your mouth. Periodontal disease triggers a systemic inflammatory response throughout your body. Bacteria from infected gums can enter the bloodstream, and the chronic inflammation they cause has been linked in multiple systematic reviews and meta-analyses to ischemic heart disease, stroke, heart failure, and peripheral artery disease. The mechanism involves both direct damage to blood vessel walls by oral bacteria and an immune response where antibodies meant to fight gum infection cross-react with components of arterial walls, promoting plaque buildup in arteries.
This doesn’t mean flossing prevents heart attacks. But it does mean that chronic gum disease is a genuine risk factor for cardiovascular problems, and daily interdental cleaning is one of the most straightforward ways to prevent gum disease from developing in the first place.
Proper Technique Matters
Flossing aggressively or with poor technique can actually cause harm. Improper flossing is a recognized cause of gingival recession, where the gum tissue pulls away from the tooth and exposes the root surface. Once that happens, you’re looking at increased tooth sensitivity (especially to cold), a higher risk of root cavities, and teeth that appear longer and uneven. The damage is largely irreversible without surgical treatment.
The correct approach is sometimes called the C-shape technique. You wrap the floss around the side of each tooth so it cups the surface, then gently rub up and down several times. The goal is to slide the floss just under the gumline until you feel slight resistance, then glide along each side of the triangular gum tissue between teeth. You should never snap or force the floss into your gums, and you should never saw back and forth at the gumline. Use a fresh section of floss for each gap so you’re not redepositing bacteria.
Floss Before You Brush
If you’re going to do both (and you should), the order matters. A randomized controlled trial found that flossing first, then brushing, removed significantly more plaque from between the teeth and throughout the mouth compared to brushing first. The reason is straightforward: flossing loosens debris and bacteria from between teeth, and brushing afterward sweeps those particles away. As a bonus, fluoride from your toothpaste can better penetrate the interdental spaces once the floss has cleared the path. The study found that fluoride levels in the mouth were higher when participants flossed before brushing.
Water Flossers as an Alternative
If you find string floss difficult to use, water flossers are a legitimate alternative. A systematic review comparing the two found that the majority of studies favored water flossers for plaque removal. In one study, string floss reduced whole-mouth plaque by about 58%, while a water flosser achieved a 74% reduction. The gap was even wider between teeth specifically: 63% reduction with string floss versus 82% with a water flosser. Not every study showed a significant difference, but none found string floss to be superior.
Water flossers are particularly useful for people with braces, dental bridges, or limited hand dexterity. The pressurized water stream can reach areas that string floss struggles with. That said, either tool works if you use it daily and with good technique. The best interdental cleaner is the one you’ll actually use consistently.
A Note on Floss Materials
Research from Harvard’s T.H. Chan School of Public Health found that certain types of dental floss, particularly Oral-B Glide and other products with a slick, glide-style coating, contain fluorine compounds indicating the presence of PFAS chemicals. Women in the study who used Glide floss had higher blood levels of one specific PFAS compound compared to those who didn’t. PFAS chemicals are persistent in the body and environment and have been linked to liver damage, immune system effects, and cancer at higher exposure levels.
This doesn’t mean you should stop flossing. The health consequences of not flossing (gum disease, tooth decay, potential systemic inflammation) are well established and more immediate than the uncertain risk from trace PFAS exposure. But if it concerns you, switching to an unwaxed floss or a natural wax floss avoids the issue entirely. Many brands now market themselves as PFAS-free.