How does toothpaste work?
Toothpaste works in a number of ways to achieve specific goals:
Food debris and plaque removal is achieved by the detergent and abrasive ingredients in toothpaste. The detergent neutralises the food debris and the abrasives remove the plaque which otherwise sticks to the surface of teeth.
Toothpaste freshens the breath by removing the food debris and bacteria which cause bad breath. The flavouring of toothpaste ensures that the mouth is infused with a more pleasant smell.
Protection against plaque is ensured by the fluoride which helps strengthen enamel, thus protecting teeth from future decay. Brushing your teeth also stimulates the production of saliva so that the mouth is moist, making it harder for plaque to stick to teeth.
Of course the motion of actually brushing is crucial to this process too. If you just put toothpaste into your mouth and didn't rub it into your teeth, the effects would only be limited. The abrasives need to be rubbed onto the surfaces of your teeth and saliva is best stimulated by the motion of brushing.
It is important to spread the toothpaste around your mouth while you are brushing so that the active ingredients can work on all of your teeth.