Traditional string flossing has long been promoted by dental professionals as a necessary complement to brushing. This practice involves using a thin filament to physically scrape plaque and debris from between teeth and beneath the gumline. However, a growing debate questions the actual benefits and safety of traditional flossing due to a lack of high-quality scientific evidence and the potential harm caused by improper technique.
The Controversy Surrounding Scientific Efficacy
The widely accepted recommendation to floss daily faces significant skepticism when held up to the standards of rigorous scientific testing. Systematic reviews that analyze the existing research often conclude that the evidence supporting flossing’s efficacy is weak or unreliable. For instance, a 2012 Cochrane review found minimal evidence that flossing, when added to brushing, consistently reduced plaque levels.
This lack of strong data gained public attention in 2016 when an Associated Press (AP) investigation highlighted the poor quality of evidence. The AP reported that the federal government quietly removed the flossing recommendation from its dietary guidelines after acknowledging that the effectiveness of the practice had never been scientifically researched to the required standard. Many of the studies supporting flossing were found to be short-term, involved small sample sizes, or carried a potential for bias, sometimes being funded by manufacturers.
While some research has indicated a slight reduction in gingivitis (gum inflammation) with flossing, the evidence level is considered unreliable. The primary issue is the absence of long-term, high-quality randomized controlled trials (RCTs) that definitively prove string flossing prevents cavities or severe periodontal disease compared to brushing alone. This scientific gap means that the routine instruction to use floss is not universally supported by robust data.
Critics argue that the purported benefits are often overshadowed by the reality that most people do not use string floss consistently or correctly. The reliance on perfect technique for a thin, manually manipulated fiber makes it a poor candidate for a universal public health recommendation. The debate centers not on whether interdental cleaning is necessary, but whether string floss is the most effective and reliable method.
Physical Damage from Improper Flossing
Beyond the questions of efficacy, string flossing presents a genuine risk of physical damage when performed with incorrect technique. Aggressive use can lead to lacerations and trauma to the delicate gingival tissue. This damage often occurs when individuals “snap” the floss down forcefully onto the gums rather than gently guiding it.
The sawing motion, commonly used to force floss through tight contacts, can also contribute to gum recession over time. This motion irritates the gingival margin, causing the gum tissue to pull away from the tooth surface, which can expose the sensitive root and lead to increased sensitivity.
A poor technique also risks pushing bacteria and debris deeper into the gingival sulcus, the small pocket between the tooth and the gumline. If the floss is not curved into a “C” shape to hug the tooth surface, it can act like a wedge, potentially deepening the pocket and exacerbating existing inflammation.
For individuals with existing dental restorations, such as crowns or fillings, careless flossing can occasionally catch an edge and dislodge or damage the repair. Consistent, rough handling can also create friction that injures the nerves within the gums.
Superiority of Alternative Interdental Tools
Because of the limitations in efficacy and the risk of trauma associated with string floss, many dental professionals now recommend alternative interdental cleaning devices. Interdental brushes are often cited as more effective than string floss at reducing plaque and gingival bleeding. These small, bristled brushes are designed to fill the interdental space and mechanically disrupt plaque over a larger surface area than a thin filament.
Interdental brushes are available in multiple sizes, allowing users to select a brush that fits the exact width of each space between their teeth. This makes them particularly effective for those with recession or larger gaps. Studies suggest they are easier to handle than string floss, which increases the likelihood of consistent and correct use.
Water flossers, or oral irrigators, offer another alternative, using a pulsating stream of pressurized water to flush out debris and bacteria from between teeth and beneath the gumline. This method is advantageous for individuals with braces, complex dental work, or limited dexterity, as it is gentler on sensitive gums and removes food particles from hard-to-reach areas. Clinical trials have indicated that water flossers can be as effective as or superior to string floss in reducing plaque and gingivitis. The hydraulic action of the water jet also provides a massaging effect that can improve gum health and reduce bleeding.