To protect against tooth decay, we are advised to brush our teeth regularly. The chemical nature of the toothpaste commonly used is:

Tooth decay occurs when bacteria inside the mouth break down food debris and produce acids that lower the mouth's $\text{pH}$ below $5.5$, causing demineralization of tooth enamel. Standard commercial toothpastes are formulated to be basic (alkaline) to safely neutralize these destructive residual acids.