Tooth decay and gum disease are caused by plaque, a sticky combination of bacteria and food. Plaque begins to build up on teeth within 20 minutes after eating. If teeth are not cleaned well each day, plaque will lead to tooth decay. If you do not remove plaque, it turns into a hard deposit called tartar that becomes trapped at the base of the tooth. Plaque and tartar irritate and inflame the gums. Bacteria and the toxins they produce cause the gums to become: br br Infected br Swollen br Tender br By taking good care of your teeth and gums, you can help prevent problems such as tooth decay and gum disease (periodontitis). You should also teach your children how to brush and floss from an early age to help them protect their teeth.