Dental plaque is the soft, sticky bacterial film that builds up on teeth — the probable cause of caries and gum disease. It forms within hours of brushing: oral bacteria colonise the tooth surface, glue themselves together with sugary polymers, and create a structured biofilm. When dietary sugars arrive, plaque bacteria ferment them into acids that dissolve enamel — the caries process — while the film itself irritates the gums into gingivitis. If left undisturbed, plaque mineralises with calcium from saliva into tartar, a hard deposit that only professional scaling removes. Control is mechanical and dietary: thorough brushing and interdental cleaning disrupt the film daily, and limiting the frequency of sugar intake starves the acid attacks. Fluoride helps by hardening enamel against the acids plaque produces.