Do you know that your mouth is the site of some very cool chemistry? And that it’s home to the hardest substance in your body? Let’s know something.
The crown of a mature tooth is composed of two unique layers. The outermost layer is the enamel.
It is the hardest and most highly mineralized substance in the human body. It is even harder than bone. But it is tissue and not a bone. This tissue has high mineral content which makes it the hardest substance.
Enamel is mainly made up of approximately 96% crystalline form of calcium phosphate known as Hydroxyapatite (Ca₁₀(PO₄)₆(OH)₂) and the other 4% is water & organic material particularly enamel-specific proteins called enamelins. That crystalline calcium phosphate is not pure crystal, because this inorganic material substituted with carbonate ions(CO3^2-) and contain trace minerals such as strontium, magnesium, lead & fluoride. The second layer underlying the rigid enamel is tougher mineralized protein-rich tissue known as Dentin, which is flexible.
However, your teeth are pretty hard but the enamel can be weakened by bacteria. We all have some bacteria in our mouths. These bacteria convert foods like sugars & starches into acids; mainly
Lactic acid (CH3CH(OH)COOH).
When there is enough acid in the mouth that the pH level drops below 5.5(a pH of 5.5 is an important pH level for teeth), then the acid begins to dissolve the Hydroxyapatite through a process called demineralization.
Ca10(PO4)6(OH)2 + 14H^+ ↔ 10Ca^2+ + 6H2PO4^- + 2H2O
(dihydrogen phosphate)
So, we do something that helps slow down the dissolution of the minerals in the demineralization phase. If we brush our teeth with toothpaste, the alkaline in the toothpaste will neutralize the acids and the lost minerals are replaced in the process called re-mineralization. And brushing our teeth is one of two everyday uses of Neutralization. The other is taking antacids.
Toothpaste’s most well-known ingredient is Sodium Fluoride (NaF), a white odorless solid that plays a large role in keeping our teeth clean. It was first used in toothpaste in
1914 and still is in toothpaste today as it keeps our tooth enamel hard & healthy.
Mohammad Masfiqul Alam Evan
Dept.of chemistry
University of Rajshahi.
Comments
Post a Comment