A toothbrush reaches only three of the five surfaces on every tooth. Here is what happens in the gaps it cannot enter, how to choose between floss, interdental brushes and a water flosser, and how to use whichever you pick properly.
The Third of Your Mouth a Brush Never Reaches
Every tooth has five surfaces, and a toothbrush can only reach three of them. The two that face the neighbouring teeth are pressed too closely together for bristles to enter, which means even meticulous brushing leaves roughly a third of each tooth untouched. At Shuster Dent this is the most common gap we find between what patients believe they are doing and what is actually happening.
It is also why so many people are surprised by a cavity. They brush twice a day, and the decay still appears — almost always between two teeth, in a place they could not have cleaned no matter how long they brushed. Cleaning between the teeth is not an optional extra for the especially diligent. It is the other half of the job.
What Actually Happens in the Gaps
Plaque is a living film of bacteria, and it starts reforming within hours of being removed. Left undisturbed between the teeth it does two things at once. It ferments the sugars and starches from your meals into acid, which dissolves enamel from the contact point inwards — a cavity invisible in the mirror that often shows up only on an X-ray. And it irritates the gum, which responds with inflammation.
That inflammation is gingivitis, and it is reversible. What follows if it is left alone is not. In periodontitis the inflammation reaches the bone holding the tooth in place, and bone that has been lost does not grow back. The spaces between the teeth are where gum disease almost always begins, simply because that is where plaque is left in peace the longest.
Floss, Interdental Brush, or Water Flosser?
Patients often ask which is best, and the honest answer is that the best tool is the one you will actually use every day. That said, the size of your gaps matters far more than the marketing does.
- Interdental brushes — small tapered bristle brushes — clean better than floss wherever they fit, and are our first suggestion for adult gaps, gum recession and cleaning under a bridge
- Floss remains the right tool where teeth sit tightly together and no brush will pass, which is common in younger mouths and crowded front teeth
- Floss picks are easier to handle than a length of string and far better than doing nothing, though it is harder to curve them properly around each tooth
- Water flossers are excellent around braces, implants and bridges, but they rinse rather than scrape and do not replace floss or a brush
- Toothpicks dislodge trapped food but do not remove the film of plaque that causes the damage
How to Do It Properly
Technique matters more than equipment, and most of the people we correct are making the same two or three mistakes.
- Guide floss gently between the teeth rather than snapping it down onto the gum
- Curve it into a C shape against one tooth, slide it just under the gum edge, move it up and down a few times, then repeat against the neighbouring tooth
- Choose an interdental brush that fits with light resistance; if it slides in loosely it is too small to clean anything
- Work in the same order every time so no gap is skipped, and do not forget behind the last molars
- Once a day is enough, and the evening is the best time — plaque left overnight gets the longest undisturbed run
Bleeding Gums, Braces and Bridges
The most common reason people give up is that their gums bleed, and they reasonably assume they are doing harm. In almost every case the opposite is true: healthy gums do not bleed, and bleeding is a sign of inflammation that is already there. Clean the area gently and consistently and it usually settles within one to two weeks. If it is still there after that, we would like to see you, because something more than plaque is involved.
Braces, bridges, implants and clear aligners all change the picture. Wires and brackets create ledges that plaque clings to, and a bridge has an underside that floss must be threaded beneath with a floss threader or a purpose-made interdental brush. If there is anything in your mouth you are not confident about cleaning around, ask us to show you — it takes two minutes in the chair and saves a great deal later.
A Small Habit With a Long Payoff
We are realistic about this. Nobody enjoys cleaning between their teeth, and telling patients to do it more rarely changes anything by itself. What does change things is finding the tool that suits your particular mouth, being shown once how to use it, and keeping it somewhere you will see it. Patients who make that switch usually notice it first as fresher breath and gums that stop bleeding, and later as check-ups where there is nothing to fix.
If you are not sure which size of interdental brush fits your gaps, or you have flossed for years without being sure you are doing it right, raise it at your next visit. We will check the spaces between your teeth, show you what works for your mouth specifically, and treat anything already there. Book a visit with us at our Haifa clinic — a few minutes spent on this is among the best-value things you can do for your teeth.