What is oral hygiene?
Like any other part of your body, your mouth has to be kept healthy and clean.  Oral hygiene means taking care of your teeth, gums, and mouth in general so they don’t become dirty, smelly, or infected. Maintaining a healthy mouth helps to keep your breath fresh and your smile beautiful. It also helps to prevent things like plaque build-up, which is a residue that coats teeth and leads to the growth of unhealthy bacteria (which can lead to halitosis, a big word that means bad breath), gingivitis, which is a bacteria that makes your gums bleed, and cavities, which are what happens when your teeth start to rot, and even simple toothaches. 

What are cavities?
Cavities are little wholes in your teeth that happen when you don’t brush and keep them clean. Cavities usually happen when you eat too much sugar and don’t brush enough. There are several known bacteria that live in every person’s mouth. Some of these bacteria are good and help us to digest food. Other ones are not so good – like the ones usually associated with cavities. 

Every person has plaque, a filmy substance that coats our teeth and houses bacteria. If we don’t brush the plaque away, the bacteria that live there multiply.  One of the bacterium that develops feeds on sugar. As it eats the sugar left in our mouths from sugary foods, it gives off an acid that actually bores through the top layer of our teeth, called enamel. Eventually, the hole can reach the nerve, which can be both painful and dangerous – the exposed nerve can become infected.  If a dentist finds a cavity in the early stages, he or she will plug up the hole by using filling. First, the dentist removes the decayed part of the tooth (enter scary dentist drill), then the hole is jammed with filling. Filling can be made of several materials, such as silver or gold.