image copyrightGetty ImagesMost of us don't use the most effective methods for brushing our teeth, despite the health risk of not doing so.For a routine most of us have been doing since before we were old enough to see in the bathroom mirror, we're remarkably bad at brushing our teeth.In Sweden, a study found that only one in ten people practice the best brushing technique.British health insurer Bupa found that almost half of people questioned did not know how to brush their teeth properly in a survey of 2,000 people in the UK. 'having not received formal instructions from his dentist or hygienist is brushing his teeth badly,' explains Josefine Hirschfeld, associate professor and specialist in restorative dentistry at the University of Birmingham in the United Kingdom.“In my experience, this will be the vast majority of people, regardless of country.” This is perhaps unsurprising, given the variety of information available on how you should brush your teeth.One study found at least 66 different, sometimes conflicting, expert opinions. "I think there's a lot of confusion for the consumer," says Nigel Carter, chief executive of the Oral Health Foundation in the UK.This confusion is amplified by the array of dental products available for purchase, from tongue scrapers to interdental hydrojets.Read also on BBC Africa:So what's wrong with most of us, and how can we change our routine to ensure we're brushing effectively?"A lot of patients understand that what they need to do is remove the leftover food," says Hirschfeld."That's only partially true. It's much more important to remove bacteria from the teeth." Consider brushing the gum line, rather than the teeth themselves.The teeth will then be brushed automatically - Josefine Hirschfeld These bacteria and other micro-organisms develop inside everyone's mouth, and form a clumped biofilm commonly called dental plaque.This biofilm is made up of about 700 different species of bacteria, the second highest diversity in the human body after the intestine, as well as a multitude of fungi and viruses."They live in the sticky film stuck to the teeth and also to the soft tissues," says Hirschfeld."This sticky film can't be easily rinsed off - it really has to be cleaned manually." The most important place to remove it is actually not the teeth, but the gum line.This is where microbes are most likely to infiltrate the gum tissue and cause inflammation, and ultimately conditions such as periodontitis.In fact, "brushing your teeth" is a misnomer."Consider brushing your gumline, rather than the teeth themselves," says Hirschfeld."The teeth will then be brushed automatically".The wide variety of dental products available can be confusing to consumers.One of the most effective methods for removing biofilm is known as the "modified Bass technique".This method requires much greater manual dexterity than the vague "put the brush in your mouth and look busy" method that many of us use, as I soon find out. In my bathroom, armed of my bamboo-handled, nylon-bristled manual toothbrush, I'm getting ready to try the Modified Bass.I glued my new miniature hourglass that clocks two minutes to the mirror (I'll come back to this later).I flip it over and start. The modified Bass technique is to place the brush at a 45 degree angle to the face of the tooth (tilted down for the lower jaw and up for the upper, like if you were almost trying to get the hairs under the gum line).You then make small vibratory movements back and forth at the level of the gum.After carefully studying several videos, I go for it. Moments later, my mirror is sprayed with white smudges of toothpaste and my brush is on the floor.In my excitement, I awkwardly handled the brush, rubbed the hard bamboo head on my gums and knocked it off. Undeterred, I swept my toothbrush clean and I tried again, this time more timidly.The quick but gentle little movements that Hirschfeld carefully described to me are surprisingly difficult to reproduce.As a right-handed person, I feel like I'm trying to write neat cursive writing with my left hand.Once I have painstakingly negotiated my entire gumline – upper, lower, inner and outer – with a Modified Bass attempt, I check my little green hourglass.My two minutes are up, I don't know how long, and I haven't even started flossing yet. There are other techniques besides Modified Bass that can effectively remove biofilm.On another occasion, I tried the modified Stillman technique - similar to the modified Bass, with the addition of a nice occasional sweeping motion away from the gum line, during which I imagine a biofilm of dirt microbial swept into a frothy oblivion.Some of the most proven methods for removing biofilm of microbes from your teeth are rarely practiced.After a week of experimenting and little toothpaste stains on the mirror as I feel like I've mastered the technique, my gums are starting to hurt a little.It turns out that in my enthusiasm, I applied too much pressure.The pressure exerted should not exceed 150 to 400 g, according to Hirschfeld, although the optimal pressure is still subject to debate.Brushing too hard, especially with a stiff bristle brush, can cause trauma to the gums.Small tears in soft tissue caused by overzealous brushing are an opportunity for bacteria to enter the bloodstream.And running the bristles of the brush over the enamel can cause tiny grooves to appear in the tooth, which add up to significant erosion over time.People who use a manual toothbrush often press harder than those who use an electric brush, many of which have sensors that warn them when the pressure is too strong.For a few days, I try a different technique, intended for children and people with less manual dexterity.The Fones method consists of holding the brush at 90 degrees and making circular movements on the teeth, touching the gum line.It's definitely easier to do while I'm trying to get the pressure correct.But I'm determined to master the modified Bass technique as soon as my gums have recovered from my eagerness."The Modified Bass technique is one of the best. It cleans the teeth in the best possible way, without causing trauma to the teeth and gums," says Hirschfeld.But Nigel Carter of the Oral Health Foundation notes, reassuringly, that it's not always important to have the right version of the manual."What dentists and hygienists generally recommend today is to look at what the person is doing and modify their existing technique to improve it," he says.Brushing your teeth for at least two minutes at a time, twice a day is recommended by the American Dental Association, NHS, Indian Dental Association, Australian Dental Association and many other organizations national health.The problem is that most of us can't estimate how long two minutes really is.The actual average duration of brushing varies widely, from 33 seconds, 45 seconds, 46 seconds to 97 seconds, depending on the different studies.According to a study by Carolina Ganss, a professor in the Department of Conservative and Preventive Dentistry at Justus-Liebig University in Giessen, Germany, only about 25% of people brush their teeth for long enough, with the right amount of pressure and movement.Luckily, there are simple solutions, like using an app on your phone, a miniature hourglass taped to the bathroom wall (as I chose to do), or an electric toothbrush with a a built-in timer.If you haven't received formal instruction from a dental professional, chances are you don't have optimal brushing technique.In general, the longer the brushing time, the more biofilm is removed, says Carter, but it's estimated that about two minutes is enough time to brush all surfaces of the teeth and the gumline.For people with gum disease or other oral health issues, however, it sometimes takes longer to make sure the biofilm has been dislodged."In fact, the optimal brushing time is highly dependent on the individual situation," says Hirschfeld."It is not really defined, and it cannot be, because each person's dental and oral situation is different. What matters is that all teeth are cleaned all surfaces of each tooth, including hard-to-reach areas - and it can easily take much longer than two minutes."In countries like the United States, United Kingdom and Australia, it is advisable to perform a carefully timed and diligently executed brushing technique twice a day.The Indian Dental Association, meanwhile, advises brushing your teeth up to three times a day (including after lunch).For most people who don't have major oral health issues, there's no benefit to going beyond this advice."You don't need to do more to remove bacteria from the teeth and it can even be harmful to brush your teeth more than twice a day" because excessive brushing risks abrading the tooth, explains Ms. Hirschfeld.But again, there are exceptions.“If you think of people with braces where food gets trapped very easily, these patients are generally advised to brush their teeth after every meal,” she adds.Brushing your teeth twice also helps guard against imperfect technique."If you brush your teeth perfectly once a day, that should be enough, because it's the older plaque that causes the problems with cavities and gum disease," says Carter."But none of us do it 100%. So the idea is that by doing it twice you get the parts you missed before, so every day you clean everything up."Is it better to brush your teeth before or after breakfast?From toothpaste manufacturers to dental hospitals, many argue that it's better to brush your teeth before breakfast than after.But this remains a matter of debate.“There is no specific, strong recommendation,” says Hirschfeld."But a lot of dentists recommend brushing your teeth afterwards, as it not only removes plaque, but also leftover breakfast foods."Whether before or after breakfast is more effective for you depends on what and when you eat.Indeed, it takes two things for a biofilm to develop: microbes, and food for them."Without bacteria or food, you can't develop cavities," says Hirschfeld."If you brush the bacteria away with a toothbrush before breakfast, the amount of sugar you eat shouldn't matter in theory. If there are no bacteria can ferment it, then it's all right."But 100% removal of biofilm in just one pre-breakfast brushing session is far from assured, especially considering most people's questionable brushing habits.Likewise, brushing after breakfast can be effective.“If the sugars layer on top of the existing bacteria and you brush them off, that should be effective as well,” says Hirschfeld.One of the main drawbacks of brushing after breakfast, however, is that you have to leave a good gap between eating and brushing – the American Dental Association recommends waiting 60 minutes.The reason for this is that the acids in food, and in the by-products of the digestion of carbohydrates by microbes, temporarily make the teeth vulnerable."The acids attack the enamel layer of the teeth and soften it for a while," says Hirschfeld.This removes some of the key components of enamel - calcium and phosphate - although they are replaced within hours by the minerals found in saliva."So the process is self-healing. But if you don't wait for that self-healing to happen, that eroded surface will become very sensitive to just being brushed."The best way to brush your teeth before or after breakfast depends on the foods you eat and how long you can wait before brushing your teeth.Dr. Carter acknowledges that the question of whether to brush your teeth before or after breakfast is nuanced and depends on what you ate.Acidic foods and drinks, such as citrus fruits, fruit juices and coffee, warrant brushing before rather than after breakfast, so as not to interrupt the remineralization process.More important than the question of breakfast is that of evening brushing, which also has a simpler answer: it should always take place the last time before bedtime."Your saliva is your natural protection mechanism," says Carter, as it inhibits bacterial growth and tooth decay."The flow of saliva decreases during the night, which is why it is very important that all plaque is removed before sleeping."There are toothbrushes and toothpastes on the market that literally "brush your teeth," says Hirschfeld.Highly abrasive toothpastes, which are often labeled as "whitening", and hard-bristled toothbrushes are notorious for this, especially when used together."It's a very slow process, taking years or decades," she explains."But over time, the teeth become abraded and can then be very susceptible to temperature or the development of cavities."Medium-bristled brushes are best for adults, as well as toothpaste that doesn't contain small abrasive particles.A smaller brush head — allowing for greater maneuverability around individual teeth — is also preferable, Hirschfeld says, as is making sure to replace a worn brush before its bristles become too misshapen.Traditional toothbrushes or chew sticks, such as the toothbrush tree miswak, widely used in Africa, the Middle East and South Asia, are also effective in removing plaque and preventing cavities .But they pose a higher risk of gum abrasion if not used correctly.The electric toothbrush is even more effective than the manual options, but also more expensive.After years of studies showing no significant difference between the two, a number of meta-analyses have found moderate levels of evidence that electric toothbrushes are more effective at removing plaque.(The authors of these meta-analyses note that they have received funding from manufacturers of electric toothbrushes in the past.)This is partly because the vibrational movement is automatic and requires less manual dexterity, but another factor is the size of the heads.Many also have pressure sensors that light up when the user presses too hard, risking damage to the enamel."But if you're using a manual toothbrush and you use it absolutely correctly in terms of brushing method, pressure, etc., you'll get just as good a result," says Hirschfeld.Despite occasional controversies over the lack of research on flossing, many dental health organizations remain strong supporters of the practice."If you think of each tooth as a cube where five surfaces are exposed to the oral environment, all of those areas have biofilms growing on them, and there's really no reason to neglect half of them," says Hirschfeld.In the UK, Carter estimates that a very small proportion - perhaps one in 20 people - habitually floss.A 2019 survey found that a third of UK adults had never flossed.Miswak, from trees such as Salvadora persica, has been used for millennia to help keep teeth clean.Flossing isn't the only way to get rid of biofilm between teeth.The characteristics of your teeth - close together or widely spaced, for example - will determine which works best, a small brush or a thin piece of dental floss.For those who have gum or tooth problems, interdental cleaning is an opportunity to put the package.“Many of our patients use a wide variety of interdental cleaning devices, so they have maybe five or six different brushes of different sizes, floss, and other brushes,” says Dr. Hirschfeld.Flossing time should be counted as part of your two-minute cleanup, she adds, and it doesn't need to be done more than once a day.This is despite a 2011 review of randomized controlled trials (RCTs) claiming that there was "weak and very unreliable evidence to suggest that flossing and brushing teeth may be associated with a slight reduction in dental plaque after one or three months", and that most of the studies had methodological flaws.However, this study was later withdrawn, after objections that "absence of evidence is not evidence of absence".A later, updated version found that flossing was significantly more effective than brushing alone in reducing gingivitis (superficial gum disease, which can later lead to deep gum disease, or periodontitis), although the evidence for plaque reduction is still "weak" and "highly unreliable"."It's really difficult to conduct these kinds of studies," says Hirschfeld.It is difficult to obtain a large enough cohort, reflecting the general population and not just dental students who are easy to recruit for this type of study, and to work around factors such as the unreliability of self-reporting .Another major challenge is to run the studies long enough to see how the incidence of tooth and gum problems is changed, which can take decades."It's difficult, if not impossible, to achieve. That's why the evidence is weak."While there are a plethora of different toothpastes, ranging from cavity prevention to whitening to sensitivity reduction, expensive brands aren't necessary to do the bulk, say Hirschfeld and Carter."I've looked at the ingredient list of some really cheap toothpastes I've seen, sometimes as cheap as 40p, and I can't see anything wrong with that," says Hirschfeld.Among the long list of ingredients on the back of the average toothpaste package, there's one ingredient in particular to watch out for: "Fluoride content," says Hirschfeld."That's definitely the key factor."It should be at least 1350 parts per million (ppm) for adults, and 1000 ppm for children, to protect the enamel from acids.Tooth enamel is the hardest tissue in the human body, and one of the hardest found in nature."It's almost as hard as diamond," notes Mr. Hirschfeld.It is mainly composed of a mineral called hydroxyapatite (a kind of calcium phosphate) arranged in a complex crystal structure, which varies in different shapes and arrangements in the tooth to increase its hardness and durability.But despite its resistance to mechanical force, enamel dissolves easily in acid.The microbes in the biofilm release lactic acid as a byproduct of the digestion of sugars and carbohydrates that can get stuck between our teeth.This lactic acid gradually draws calcium and phosphate from the enamel, which eventually crumbles and forms a cavity.Compounds naturally present in saliva can help replace lost minerals.In particular, if fluoride is present (as is naturally present in soils and water in many parts of the world), the glaze reforms to fluorapatite, which is more acid resistant than hydroxyapatite.Spitting out the toothpaste when you're done, but not rinsing it off, allows the fluoride to stay on the teeth longer, for added protection.“Since fluorides were introduced into toothpaste, the incidence of cavities has decreased wherever fluoridated toothpaste is used,” says Hirschfeld.However, some trendy ingredients should be treated with caution.Charcoal, which has been used to clean teeth for millennia and has become increasingly popular in commercial toothpastes, is less well documented.There is little evidence that charcoal whitens teeth, and it may increase the risk of dental erosion and other problems.According to a study, claims about the antibacterial, antifungal and antiviral properties of charcoal toothpastes cannot be substantiated, and dentists should "advise their patients to be cautious when using charcoal and [products dental products] based on charcoal whose effectiveness and safety have not been proven".Many charcoal toothpastes do not contain fluoride and therefore offer less protection against cavities.However, if a person uses toothpaste without added fluoride, they will still get some benefit from brushing their teeth."She can still get mechanical plaque removal," Carter says."But she won't get the benefit of preventing cavities, which is essentially the role of fluoride in toothpaste."Other popular toothpaste additives may be less controversial.According to the authors of a meta-analysis, toothpastes containing baking soda (small crystals of sodium bicarbonate) remove dental plaque better than those without, while pointing out that other studies of follow-up were needed (the authors of this study said they had received funding from toothbrush and toothpaste manufacturers in the past).The same analysis found that baking soda toothpastes may lead to a slight reduction in bleeding due to gingivitis.Mouthwash is less effective than brushing at removing plaque, says Carter, but when combined, the two can remove slightly more plaque than brushing alone.“I would say it is a very useful additional element, not to replace brushing your teeth but to complement it”.It may, however, be useful for treating gingivitis, according to a recent consensus statement.To be useful, it must contain at least 100 ppm fluoride and be clinically proven to reduce plaque.And it's best to use it only if your gums are already bleeding, rather than as a preventative.An old, worn-out toothbrush does not clean teeth as effectively.For lack of a better term, there may be a "sweet spot" for brushing your teeth effectively.Not enough brushing, and biofilm builds up and risks causing cavities and periodontitis.Too much brushing or brushing too hard, and the enamel wears off easily over time.While the ideal routine — with floss or interdental brushes, and perhaps mouthwash if you have gingivitis — can be laborious, it's worth it for the overall health gain.As we saw in the first part of this series of articles, effective brushing proves to be an effective way of reducing the risk not only of bad breath, yellow teeth and cavities, but also of developing diseases such as as type 2 diabetes, cardiovascular disease and cognitive decline."Growing evidence suggests that inflammation is one of the pathways linking periodontal disease and cognitive impairment," says Bei Wu, Dean Professor of Global Health at the University of New York's Rory Meyers College of Nursing. York."Good oral hygiene behaviors, such as effective tooth brushing, can reduce plaque and the risk of gum inflammation."With that in mind, my now-thriving collection of brushes, interdental devices, dental floss, and a new bathroom timer doesn't seem so excessive after all.© 2022 BBC.The BBC is not responsible for the content of external sites.Learn about our approach to external links.