Removing plaque from between your teeth requires a mechanical tool that physically reaches the tight spaces your toothbrush misses, and the best tool depends on the size of your gaps, your dexterity, and what you’ll actually use consistently. String floss is the traditional recommendation, but the research on its effectiveness is more ambiguous than most people realize, and interdental brushes outperform floss in head-to-head trials for many people. The real challenge is less about picking the perfect device and more about understanding how each one works, using it correctly, and sticking with it day after day.
Why Interdental Plaque Matters
Your toothbrush, no matter how good, cleans the outer, inner, and biting surfaces of your teeth but struggles to reach the contact points where teeth touch and the curved surfaces just below those contact points. Plaque in these spots matures quickly into a structured biofilm, a living community of bacteria that produces acids and toxins right against the gum tissue. When interdental plaque is allowed to accumulate, it correlates strongly with gingival inflammation. One study found a clear relationship between the composition of interdental plaque and bleeding on probing, a standard clinical marker of early gum disease.1Photodiagnosis and Photodynamic Therapy. Red fluorescence of Interdental plaque for screening of gingival health The interproximal surfaces are also where cavities between teeth develop, making this area a two-front problem for both your gums and your enamel.
What the Evidence Actually Says About String Floss
If you grew up hearing that you must floss every day, you might be surprised by the science. A systematic review of studies comparing brushing alone to brushing plus flossing found that a greater part of the research did not show a clear benefit for floss on plaque levels or clinical signs of gum inflammation.2PubMed. The efficacy of dental floss in addition to a toothbrush on plaque and parameters of gingival inflammation: a systematic review That does not mean floss is useless. A randomized trial found that adding floss to brushing did not significantly reduce interproximal plaque, but it did reduce interproximal gingivitis by about 5% and cut gingival bleeding by roughly a third over four to twelve weeks.3PubMed Central. Efficacy of flossing and mouth rinsing regimens on plaque and gingivitis: a randomized clinical trial
That disconnect, where floss reduces bleeding and inflammation without always removing measurably more plaque, is one of the stranger findings in dental research. One explanation is that floss disrupts the biofilm’s structure without fully scraping it away. A recent investigation into flossing performance noted that in some cases, researchers actually found more stained plaque after flossing than before, yet the mechanical disruption of the biofilm still appeared to benefit gum health independently of visible plaque removal.4PubMed Central. Does proper flossing performance translate into effective plaque removal? So floss may be doing something meaningful even when plaque scores don’t budge. The takeaway is not to abandon floss, but to understand that the benefit is real and somewhat modest, and that technique matters enormously.
Interdental Brushes Remove More Plaque
If your interdental spaces are large enough to fit a tiny brush between them, interdental brushes consistently outperform string floss for plaque removal. In one trial, patients using interdental brushes saw their plaque scores drop from about 3.1 to 2.2 over six weeks, while floss users dropped from 3.1 to only 2.5. The brushes removed significantly more plaque, and they also produced a larger reduction in probing depth.5PubMed. Comparison of different approaches of interdental oral hygiene: interdental brushes versus dental floss Another randomized controlled trial found that by twelve weeks, the interdental brush group had improved more than the floss group in plaque, papillae condition, and probing depths.6PubMed. Comparison of interdental cleaning methods: a randomized controlled trial
The catch is sizing. Interdental brushes come in a range of diameters, and the brush needs to fit snugly enough to contact the tooth surfaces on both sides of the gap. If the brush is too small, it slides through without cleaning effectively. If it’s too large, you can’t insert it without forcing it and risking tissue damage.7PubMed Central. Creation of a Systematic Interdental Brush Set Based on the Passage Hole Diameter (PHD) – An In-Vitro Study Most people have gaps of different sizes around their mouth, so you may need two or three sizes. A dentist or hygienist can measure your passage hole diameters and recommend specific sizes, which is the approach dental researchers increasingly advocate for rather than the one-size-fits-all approach many people take at the pharmacy.
For people with tight contacts, especially younger adults whose gum tissue fills the interdental space completely, the smallest interdental brush may still not fit. In those cases, string floss remains the go-to tool because it can slide through contact points that a brush cannot.
Water Flossers and How They Compare
Water flossers (also called oral irrigators) use a pulsating stream of water to flush debris and disrupt biofilm between teeth. The mechanism relies on the shear stress that the water generates against the tooth surface, which physically detaches portions of the plaque biofilm.8PubMed Central. Removal of interproximal dental biofilms by high-velocity water microdrops A systematic review comparing water flossers to string floss concluded that water flossers were more effective for plaque removal, especially from hard-to-reach interproximal areas.9PubMed Central. Comparing the effectiveness of water flosser and dental floss in plaque reduction among adults: A systematic review
That said, individual trials are not always so decisive. A randomized trial of orthodontic patients wearing fixed braces compared water jet flossing to interdental flossing over two weeks. Both groups saw meaningful drops in plaque and bleeding. The water flosser group did slightly better, with about a 22% reduction in plaque versus 16% for the floss group, but the difference between the two was not statistically significant.10PubMed Central. The effectiveness of water jet flossing and interdental flossing for oral hygiene in orthodontic patients with fixed appliances: a randomized clinical trial Water flossers are a solid option, particularly for people who find manual flossing difficult or who have braces, bridges, or implants that create hard-to-reach areas. They’re also gentler on the gums, which makes them appealing if you tend to cause bleeding or soreness with string floss.
Floss Picks, Rubber Picks, and Other Handheld Tools
Floss picks, those Y-shaped or F-shaped plastic handles with a short strand of floss stretched between two prongs, are enormously popular because they’re easier to use one-handed. Research suggests they’re at least as effective as traditional finger-wound floss for plaque removal. One crossover study found that a floss pick removed about 19% of plaque compared to 15% for standard rolled floss, and a conservative analysis confirmed the pick was at least equivalent.11PubMed. Evaluation of the plaque removal efficacy of two commercially available dental floss devices Another study of a different handled flosser found no significant difference from finger flossing, and over half the participants preferred the handled version.12PubMed. Comparison of the plaque removal efficacy of a new flossing aid (Quik Floss) to finger flossing If a floss pick is what gets you to clean between your teeth every day, it’s a perfectly reasonable choice.
Rubber or elastomeric interdental picks, the soft cone-shaped silicone tips that slide between teeth, are a newer category. A systematic review found that these rubber-bristle cleaners produced comparable plaque scores to both string floss and interdental brushes. For bleeding, results were mixed: some studies found rubber picks were better at reducing bleeding at accessible sites, while one study showed interdental brushes achieved greater gum inflammation reduction overall. Participants generally preferred the rubber picks and experienced fewer gingival abrasions.13PubMed Central. The efficacy of a rubber bristles interdental cleaner on parameters of oral soft tissue health‐a systematic review An in vitro study comparing interdental brushes to rubber picks directly found the brushes cleaned about three times as effectively, removing roughly 58% of simulated plaque versus 18% for the rubber picks.14PubMed Central. In vitro comparison of cleaning efficacy and force of cylindric interdental brush versus an interdental rubber pick Rubber picks are comfortable and convenient, but if thorough plaque removal is your priority and an interdental brush fits your spaces, the brush is the stronger performer.
Why Technique Trips People Up
With any interdental tool, how you use it matters as much as which one you pick. For string floss, the proper motion is a C-shape hugging each tooth surface, sliding gently below the gumline and moving up and down rather than sawing back and forth. Aggressive sawing can cut into gum tissue, and habitual improper technique has been linked to actual bone loss in case reports. One published case described a patient with excellent overall hygiene who nonetheless had gingival clefting and angular bone loss at several sites, attributed to an incorrect flossing method rather than periodontitis.15PubMed. Periodontal bone loss associated with an improper flossing technique: a case report That’s an extreme outcome, but garden-variety gingival nicks and cuts from overly forceful flossing are common enough to discourage people from continuing.
For interdental brushes, the key is choosing the right size so the bristles make contact with both adjacent tooth surfaces without needing to force the brush through. You should be able to insert it gently and move it back and forth a few times. The brush does the work through bristle contact, so jamming a too-large brush into a tight space is counterproductive and painful.
For water flossers, technique is simpler: aim the tip at the gumline at roughly a 90-degree angle to the tooth, pause briefly at each interproximal space, and let the water do its job. Most people benefit from starting on a lower pressure setting and working up.
Building the Habit
The most effective interdental cleaning tool is the one you actually use. Research into the psychology of flossing habits has found that the strongest predictors of consistent flossing aren’t knowledge about plaque or fear of cavities. People with more positive attitudes toward flossing, prior experience with the behavior, and stronger prospective memory (the ability to remember to do planned tasks) flossed more often. Interestingly, people who flossed after brushing rather than before tended to form stronger habits, and at eight-month follow-up, they flossed more frequently.16PubMed. Forming a flossing habit: an exploratory study of the psychological determinants of habit formation
Planning also matters. A study of university students found that making a concrete plan specifying when, where, and how you’ll floss was a stronger predictor of actually doing it weeks later than any of the standard motivational measures like perceived benefits or self-efficacy.17PubMed. Adherence to a daily flossing regimen in university students: effects of planning when, where, how and what to do in the face of barriers Dental hygienists are increasingly recognizing that promoting habit formation strategies and addressing specific barriers matters more than lecturing patients about gum disease risk.18Journal of Dental Hygiene. Habits, Practices and Beliefs Regarding Floss and Mouthrinse among Habitual and Non-Habitual Users If you’ve struggled with consistency, pick the tool that feels least like a chore, pair it with brushing as an anchor habit, and decide in advance exactly when in your routine you’ll do it.
Mouthwash as a Supporting Player
Mouthwash cannot replace mechanical cleaning between teeth, but certain formulations can help. Antiseptic mouthwashes containing essential oils have been shown to penetrate plaque biofilm, and chlorhexidine rinses bind to the bacterial cell membranes and work against the biofilm’s structure.19PubMed. Penetrating the plaque biofilm: impact of essential oil mouthwash Chlorhexidine is the strongest antimicrobial rinse available, but it stains teeth with long-term use and tastes unpleasant, so it’s usually prescribed for short-term use after surgery or during acute gum problems rather than as a daily habit. Over-the-counter essential oil rinses (the Listerine-type products) are more practical for daily use and provide a modest additional benefit on top of mechanical cleaning. Think of mouthwash as insurance for the spots your brush or floss missed, not a substitute for reaching those spots mechanically.
Cleaning Around Braces and Other Hardware
Fixed orthodontic appliances create a cleaning nightmare. Brackets, wires, and bands create dozens of new surfaces and nooks where plaque accumulates, and traditional flossing becomes difficult because the wire blocks access from above. Threader floss can get under the wire, but it’s slow and tedious. Water flossers are popular among braces wearers for good reason, since the pressurized stream can reach around brackets without threading. Interdental brushes also show promise around brackets. An in vitro study found that cylindrical interdental brushes achieved better cleaning performance around brackets than waist-shaped brushes.20Swiss Dental Journal SSO. Cleaning potential of interdental brushes around orthodontic brackets – an in vitro investigation
For patients with both braces and micro-implants (temporary anchorage devices), research suggests a multi-tool approach works best: a specialized two-row toothbrush for cleaning above and below the archwire, plus a single-tuft brush for cleaning around individual bracket locks and around the implant sites.21Ukrainian Dental Journal. Improvement of self-performed oral hygiene among patients with braces and micro-implants: approbation of specifically designed plaque-controlled regime If you’re in orthodontic treatment, ask your orthodontist to walk you through a specific cleaning protocol rather than trying to figure it out with standard tools alone.
Disclosing Tablets and Self-Monitoring
Plaque-disclosing tablets or solutions stain bacterial plaque a bright color (usually pink or purple), making it visible on your teeth. The idea is that if you can see where the plaque is, you’ll be better at removing it. One study of dental students found that disclosing agents enhanced the ability to visually monitor plaque and make real-time adjustments to cleaning technique.22PubMed Central. Plaque disclosing agent as a plaque control guide for oral hygiene in chronic periodontitis based on guided biofilm therapy: A retrospective cohort study However, another randomized trial in dental students found no significant difference in plaque or gingival index between groups that used disclosing agents and those that didn’t.23PubMed Central. Effect of plaque-disclosing agents on biofilm removal: single-center randomized trial in fourth-year dental students
That mixed evidence may reflect the population studied (dental students already know how to clean their teeth). For someone who has never thought much about where plaque hides, using a disclosing tablet once a week for a few weeks can be genuinely eye-opening. You’ll quickly see that your toothbrush leaves the interproximal surfaces largely untouched, which is a more persuasive motivator than any lecture about gingivitis. Even if the long-term clinical benefit is uncertain, the short-term educational value of seeing stained plaque clustered between your teeth and along the gumline can change your habits.
Daily Flossing and Bacteremia
Here’s a quirk of dental biology that rarely gets discussed outside periodontology circles: flossing introduces bacteria into your bloodstream. About 30 to 40% of people show detectable bacteremia after flossing, meaning live bacteria circulating in their blood. One study found that 40% of periodontitis patients and 41% of healthy patients had bacteremia after flossing, with viridans streptococci, which are commonly implicated in heart valve infections, making up over a third of the isolated organisms.24PubMed. Bacteraemia due to dental flossing Another study put the bacteremia rate at 30% for flossing, which was statistically indistinguishable from the rate caused by professional scaling and root planing.25PubMed. Incidence and magnitude of bacteraemia caused by flossing and by scaling and root planing
Before you swear off flossing: for healthy people, these brief episodes of bacteremia are harmless and your immune system clears them within minutes. The concern is limited to people with specific heart conditions like artificial heart valves or a history of endocarditis. And there’s an ironic twist. An older study found that people who flossed daily developed no bacteremia at all, while people who delayed flossing for one to four days developed bacteremia 86% of the time.26PubMed. Dental flossing and its relationship to transient bacteremia The interpretation is that regular flossing keeps the gum tissue healthy and tight, reducing the bacterial load and the ease with which organisms enter the bloodstream. Sporadic flossing, on the other hand, combines inflamed gums full of bacteria with the mechanical disruption that lets them in. If you’re going to floss, the safest approach is to do it consistently rather than once every few days when guilt strikes.
The Environmental Side of Interdental Cleaning
Billions of floss picks, plastic-handled interdental brushes, and floss containers end up in landfills every year. A life-cycle analysis of interdental cleaning aids found that bamboo interdental brushes had the lowest climate-change impact, though the study noted that bamboo is not a perfect sustainable material. It requires water, fertilizers, and cropland, and as demand for bamboo products grows, the environmental benefit may shrink. Recycled plastic products actually outperformed bamboo in some environmental categories for toothbrushes, and a similar principle likely applies to interdental tools.27PubMed Central. An environmental impact study of inter‐dental cleaning aids If environmental impact matters to you, look for biodegradable floss (silk-based or charcoal-infused options in refillable containers), reusable interdental brush handles with replaceable heads, or a water flosser, which produces no disposable waste at all beyond the electricity it uses.