The main cause is gum disease. A 2010 study found that 47 per cent of Americans over 30 had some degree of gum disease. The bacteria attack the bone tissue in your jaw just behind the gum and cause it to slowly erode. Without healthy bone tissue to act as a scaffold, the gums first peel away from the tooth and eventually shrink back. Regular toothbrushing and flossing can fight gum infection but overbrushing damages gums too.
Why is it only our teeth that need cleaning twice a day?
Teeth are the hardest structures in the human body, but as a direct consequence of this, they are also uniquely vulnerable.
Tooth enamel is hard because it is almost entirely composed of an inorganic mineral called hydroxyapatite (a form of calcium phosphate). But acids can attack inorganic minerals, both those directly present in fruit and those produced by the bacteria in our mouths as they digest sugars. Worse still, enamel cannot be regenerated once the tooth has formed. This means that any damage to the enamel is cumulative over your lifetime.
Brushing your teeth regularly helps keep mouth pH from dropping too low and reduces bacteria. Washing the outside of your body is more about removing dirt, pheromones and bacteria rather than preventing damage to the skin itself. Skin is mostly impervious to these substances and is constantly sloughing away and regenerating itself from below anyway.
What’s the best way to brush your teeth?
A recent study by Prof Aubrey Sheiham and colleagues at University College London found an “unacceptably inconsistent array of advice” from dental associations, dentists and toothbrush companies.
Some dentists claim a side-to-side motion is fine, while others insist on different actions in different parts of the mouth. The most common advice is jiggling the brush back and forth. According to Sheiham, there’s no evidence any of these are better than just scrubbing. He recommends brushing from side to side, with the brush at a 45-degree angle and held lightly. He suggests focusing on where plaque is most likely to collect, which is biting surfaces and where teeth meet gums.