You should floss at least once a day.
The overall evidence, including reviews by Marchesan et al, Ng and Lim, and Worthington et al all discuss the advantages of interdental cleaning. The overwhelming evidence supports regular interdental cleaning for your oral health.
These reviews also go on to compare different types of interdental cleaning.
You could see more benefit by switching to a different type of interdental cleaning, such as interdental brushes or a water flosser.
But when it comes to how often you should floss, there is no definitive evidence saying that it definitely needs to be once per day.
It is a little contradictory, but some people can clean less often without it having a negative effect on their oral health.
A 2017 research paper studied the association between how often you floss and whether or not you have periodontal disease. They confirmed there are definitely benefits of flossing for gum health. But they also concluded that “flossing 2–4 days a week could be as beneficial as flossing more frequently”.
However, these cases are rare and would only apply if you were able to clean interdentally less often and know that it wasn’t having a negative effect.
My advice would be to continue to floss daily, unless you are told otherwise.
Getting started with flossing? See our quick start guide to making this a healthy habit
Flossing is a difficult task.
Learn about the correct technique here.
Making it a habit can be even more difficult.
Visit our page How To Start A Flossing Routine And Make It A Habit for a host of useful tips!
Why is flossing important?
The purpose of flossing is to remove plaque and food debris from between the teeth.
When you brush your teeth with a manual or electric toothbrush, you are only reaching 60% of the tooth surface.
It is important to reach that 40% between the teeth, the interdental spaces.
Plaque is a sticky substance that contains bacteria. It on your teeth builds up over the course of the day.
It is bacteria in plaque that causes tooth decay and gum disease.
This is because bacteria produce acids which irritate your gums. This irritation results in redness with bleeding, swelling and tenderness. This is gingivitis, the early stages of gum disease.
Failing to remove plaque will also result in the plaque hardening into something referred to as tartar or calculus. This is impossible for you to remove at home.
Long term, if gingivitis is not treated it can progress into periodontitis.
Using interdental cleaning tools such as dental floss disrupts the plaque formation. It helps achieve a good level of oral hygiene.
The Cochrane Collaboration did a review of many studies and found that
“despite the uncertain or low quality of most of the studies, and given the importance of avoiding plaque deposition, plus the absence of any major disadvantages, these results support the use of regular flossing with toothbrushing.”
For more advice on the basics of keeping your mouth healthy, see our teeth brushing guide.
When should you floss — day or night?
The general consensus in the dental community is that the gold standard would be to floss in the evening.
This ensures that there is no plaque or debris left overnight. Bacteria left overnight have the potential for most damage due to less protective saliva and less movement of the tongue.
That said, it depends what works for you.
The Mouth Healthy website sums up the general feeling and recommendations well:
“The most important thing about cleaning between your teeth is to do it. As long as you do a thorough job, it doesn’t matter when. Pick a time of day when you can devote an extra couple of minutes to your dental care. People who are too tired at the end of the day may benefit from cleaning between their teeth first thing in the morning or after lunch. Others might like to go to bed with a clean mouth.”
Should you floss before or after brushing?
When you floss, do it before you brush your teeth.
This way, the plaque and debris from the interdental spaces are removed prior to brushing.
When you brush, the protective toothpaste reaches in between the teeth so it has greater benefit. The toothpaste is also not removed by flossing, as you have already done this.
This is supported by a 2018 clinical trial published in the Journal of Periodontology. They concluded:
“flossing followed by brushing is preferred to brushing then flossing in order to reduce interdental plaque and increase fluoride concentration in interdental plaque.”
Can you floss too much?
As with everything in life, moderation is key.
There is no direct evidence to support the fact that you could be flossing too much. As long as your technique is good, you are unlikely to do any harm flossing more than once a day.
Flossing once a day is a minimum.
Is flossing twice a day too much? No.
Flossing twice a day is also okay. In fact, many dental professionals will recommend this as it means you clean all the gaps every time you brush.
Floss more often than this and you are unlikely to see much benefit for the effort that it takes.
After all, once your teeth and gums are clean, they are clean!
Excessive flossing will use up more product, whether that is floss or interdental brushes. This costs you and the environment more.
Should I floss after every meal?
Flossing once a day is the minimum. Twice a day is also recommended.
Some people find that they like to floss after they eat.
It is not necessary for most people to floss after every meal.
But if you find that you get food stuck between your teeth, you could floss to remove this. It will prevent bad breath developing and help keep the teeth clean.
I would also recommend some sort of interdental cleaning after every meal if you are wearing braces, whether they are removable or fixed. That is because people undergoing orthodontic treatment are at higher risk of gum disease and decay. For you it is important to keep everything as clean as possible.
Choosing a flossing product
Most of our posts talk about flossing, because that is the term that most people are familiar with.
But there are a variety of ways you can achieve plaque removal between your teeth. The more general term is interdental cleaning.
The tools that can be used for interdental cleaning include floss, interdental brushes and water flossers. Each has a slightly different approach to achieve a similar end result. I explain the differences between them here.
Choosing can be daunting, but don’t let the challenge of deciding on the correct product stop you doing interdental cleaning. If you are confused, you can ask your dental professional for help choosing the right method for you.
The most important thing is that you clean between your teeth.
It is best for you to go to your own dentist or hygienist. They will make you your own personalised plan that is unique for your mouth.
Floss is the most commonly used and advised tool, due to the cost and simplicity of the product.
Floss is one of the thinner products and glides easily in the tightest of spots between teeth.
It is a length of string made from material such as nylon or silk. It is wrapped around your fingers and slid down between the teeth. Some floss is made up of material twisted or braided together.
There are different brands and styles available, to find out more check out our guide to the most popular types of floss.
Floss is also used in the style of a flossette or floss holder. Holders can make floss easier to use.
You might be advised to use floss in conjunction with interdental brushes. It can be used to reach and fit in areas that the brushes cannot.
Interdental brushes are small sticks with tufts coming out of them.
They are designed to slide into the interdental area – the gap that exists between teeth and that is occupied by the gums – rather than be pulled down between the teeth
Interdental brushes come in different sizes to help you clean these different sized gaps between the teeth. They are especially useful for larger gaps and for people with more advanced gum disease.
See our post on the best interdental brushes for more information.
Water flossers use a specialised powered handle to push water into the gap between the teeth.
Water flossers are more expensive to buy but can be more effective and more enjoyable to use.
The recommendation from professionals is that you use a water flosser in addition to floss or interdental brushes. But this is often not the case.
Dentists would prefer you use a tool that you would prefer to use regularly than the one you struggle with or simply won’t use.
If the idea of a water flosser sounds interesting, check out our post on the best electric dental flossers.
The take home message is that you need to be flossing once a day.
Interdental cleaning is also most effective if you do it before brushing your teeth, before going to bed.
But if you truly don’t feel you can commit to that, then the most important thing is to get into a habit of doing it once per day, regardless of time.
And of course, flossing may be replaced by interdental brushes or a water flosser.