Nobody who only brushes is cleaning their teeth: a brush cannot reach the surfaces where two teeth touch, and that is where decay and gum disease start.
Plaque is a soft film of bacteria that forms on teeth continuously, within hours of them being cleaned. Left alone it produces the acid that causes decay and the inflammation that causes gum disease, and after a day or two it begins to harden into calculus, which no amount of brushing will shift.
Removing it is two jobs rather than one. A toothbrush reaches the outer, inner and biting surfaces. It cannot reach the surfaces where two teeth touch, and those are precisely where decay between teeth and gum disease tend to start. Nobody who only brushes is cleaning their teeth.
Brushing
Twice a day, for two minutes, and one of those times last thing at night. The night brushing is the more important of the two: saliva flow drops during sleep, so the mouth loses its own washing and buffering for several hours, and fluoride left on the teeth at bedtime does its most useful work.
A small-headed brush with soft or medium bristles reaches further back and around the curves than a large one. The bristles go against the tooth at roughly forty-five degrees to the gum margin, so that they reach slightly into the crevice between tooth and gum, and move in small circles — a few teeth at a time, outer surfaces, inner surfaces, biting surfaces, in the same order every time so that nothing is habitually missed. The inner surfaces of the lower front teeth and the outer surfaces of the upper back teeth are the two places most commonly skipped, along with the back of the last molar, which has no neighbour to guide the brush.
The commonest mistake is brushing too hard. Vigorous horizontal scrubbing along the gum line does two kinds of damage that do not reverse: it wears a groove in the softer tooth surface at the neck of the tooth, which is what causes sensitivity to cold there, and it makes the gum recede, exposing root surface that decays faster than enamel. Gums that have receded do not grow back. Light pressure, with the bristles bending only slightly, cleans better than force; a brush head that splays within a few weeks is reporting that the pressure is too high. Many electric brushes have a pressure sensor for exactly this reason, and it is worth paying attention to.
Spit out and do not rinse. Rinsing with water washes away the fluoride that was the point of brushing, and so does a mouthwash used immediately afterwards.
Do not brush straight after anything acidic — fruit juice, fizzy drinks, wine, vinegar — or after being sick. Acid temporarily softens the enamel surface, and brushing it in that state removes it. Rinsing with plain water and waiting an hour avoids the damage.
Electric or manual? Powered brushes, particularly the oscillating-rotating kind, remove modestly more plaque and reduce gum inflammation somewhat more than manual brushing, which makes them worth having for most people and genuinely valuable for anyone with limited dexterity. But the margin is modest, and a manual brush used carefully for two minutes beats a powered one run round the mouth in thirty seconds. The technique and the time matter more than the hardware.
Toothpaste. The only thing that reliably matters is the fluoride content: 1,350 to 1,500 parts per million for adults and children of seven and over. Beyond that, toothpastes differ mainly in flavour and in extra ingredients that may help specific complaints — potassium or stannous compounds for sensitivity, higher-fluoride versions on prescription for anyone with active decay. There is no UK equivalent of the approval seals printed on packaging in some other countries, so the figure on the tube is the thing to read.
The brush itself. Replace it every three months, or sooner once the bristles splay. Rinse it after use, stand it upright to dry in open air, and don't share it. Toothbrush sanitisers, dishwashers and microwaves are unnecessary, and the last two damage the brush. Throwing out a brush after a cold is a widespread habit with no good evidence behind it; reinfection with one's own virus is not how it works.
Cleaning between the teeth
This is the part most people skip, and it is where the disease is.
Interdental brushes are the first choice wherever the spaces allow one to pass. Small tapered or cylindrical brushes on a handle, they are easier to use well than floss and the evidence gives them a modest edge for gum health. Size is the thing that matters: a brush too small does nothing, one too big damages the gum, and the spaces in one mouth are not all the same size. A dentist or hygienist will size them, which takes a couple of minutes and makes the difference between a drawer full of useless brushes and a routine that works.
Floss is for the spaces too tight for a brush, which in many mouths means the front teeth and nowhere else. It is worked gently between the teeth rather than snapped down onto the gum, curved against the side of one tooth in a C shape, and moved up and down against that surface before the same is done for the neighbour.
One point of technique is worth stating plainly, because it is often got backwards. The aim is to reach gently just below the gum margin, where plaque collects. Avoiding the gum entirely leaves the plaque exactly where it does the damage. Touching the gum is the job; cutting or bruising it is not, and the difference is in gentleness rather than in distance.
Single-tufted brushes — a small round head of bristles on an angled handle — are useful for crowded teeth, the back of the last molar, and around implants, bridges and orthodontic brackets.
Water flossers help some people, particularly around fixed braces and bridgework where a brush or floss is awkward. They are an addition rather than a replacement, because a jet of water does not scrub a surface.
Once a day is enough, at whatever point in the routine it will actually happen. If the gums bleed when daily cleaning starts, that usually means inflammation was already there and the cleaning is reaching it; it generally settles within one to two weeks. Bleeding that carries on beyond that, or gums that bleed without being touched, is a reason to see a dentist rather than to stop.
Mouthwash, tongues and dentures
Mouthwash is an addition to brushing and interdental cleaning, never a substitute for either, and it should be used at a different time of day so that it does not wash fluoride off the teeth. A daily fluoride rinse is genuinely useful for people prone to decay. Chlorhexidine mouthwash is a short-course treatment for specific situations rather than a daily habit, since prolonged use stains teeth and alters taste. Alcohol-free versions are more comfortable for anyone with a dry mouth.
The tongue holds bacteria and the coating on it is a common cause of bad breath. A soft brush or a tongue scraper, used gently from back to front, deals with most of it. Persistent bad breath despite good cleaning is worth investigating rather than masking, since it can point to gum disease, a dry mouth, or something outside the mouth entirely.
Dentures are cleaned twice a day over a bowl of water, with a brush and a cleaner intended for them rather than toothpaste, which is too abrasive for the acrylic. They come out at night, and are kept in water or a denture solution. Where some natural teeth remain, those and the gums under a partial denture need their own cleaning, because the edge of a denture traps plaque against whatever it touches.
Two things that make the rest harder
Smoking. Besides the staining, tobacco reduces blood flow in the gums, which means gum disease progresses without the bleeding that would otherwise signal it. Smokers lose more bone around their teeth, respond less well to treatment for gum disease, and have the main modifiable risk factor for mouth cancer.
A dry mouth. Saliva washes away sugar and acid, buffers the mouth and carries the minerals that repair enamel. Many common medicines reduce it, as do some conditions and some treatments. Anyone whose mouth is persistently dry is at markedly higher risk of decay and should say so at the dentist, because the preventive measures change.
What professional cleaning adds
Once plaque has hardened into calculus, brushing cannot remove it, and its rough surface holds more plaque against the gum. Removing it is what a scale is for, and it is also the point at which a hygienist can see which parts of the mouth are consistently being missed and show what to do differently — which is worth more over a lifetime than the cleaning itself.
See also gum disease, tooth decay and cavities, fluoride and teeth and dental check-ups.
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