First of all, let me explain what is toothpaste and what is it made from. Toothpaste is basically a gel or paste dentifrice used with toothbrush to maintain oral hygiene and clean our teeth and gum. It can prevent tooth decay and the formation of dental plaque by delivering active ingredients such as fluoride and xylitol.
As you can see, the part which we are brushing everyday is the outermost layer, the enamel. 95% of enamel is made from a hard and strong subtance, called hydroxyapatite, Ca10(PO4)6(OH)2. Although hydroxyapatite is strong and firm, it is easily decay if attacked by acid. The reaction occurs is:
This equation means that the reaction will proceed toward the right side by the addition of acid (H+ ion). Thus, the more acid added, the more hydroxyapatite that is dissolved into the saliva. This reaction is called 'decalcification'. Eventually, the enamel will start to decay and thus, plaque is formed.
You don't want your teeth to look like this right? Okay, continue reading then. =D
Now we shall see how toothpaste works to prevent decalcification or tooth decay! For your information, most of the food we consume are composed of different types of food acid. For instance, malic acid (apple), tannic acid (tea) and tartric acid (carrot).
Toothpaste act as a base which neutralise the acids in our mouth. From the above equation, we know that acids attack the teeth and the enamel diffuses into calcium ions and HPO4 2- ions. When we brush our teeth with toothpaste, fluoride ions are delivered to the enamel and replaces the OH ions in hydroxyapatite, to form fluoroapatite, Ca10(PO4)6F2. The reaction occurs is:
Ca10(PO4)6(OH)2 + 8H+ ---> 10 Ca2++ 6HPO42+2H2O
Last but not least, remember to brush your teeth at least twice a day, and also after meal!
Save your smile! =DThanks for reading and have a good day!