If you plan to spar as part of your boxing training, having a mouth guard, or mouthpiece as they are sometimes called, is a must.
There are two different designs. One design fits over the top row of teeth. The other design fits over both rows of teeth, with a hole in the middle for breathing purposes.
The purpose of a mouth guard is to protect your teeth as well prevent a boxer from being knocked out, to an extent. Mouth guards can be purchased at any sporting goods store, but don't go too cheap on the price. But don't pay big money unnecessarily, either. I had a salesperson in one of those big, popular sporting good chain stores try to talk me into getting up off of $75.00 for a mouth guard. If I was a professional boxer, I might have considered paying that much, but as an amateur boxer, no.
Most mouth guards are the boil and bite type. Let a pot of water boil, stick the mouth guard in the water for as long as the instructions say to do that, then put it in the mouth. Allow it mold to the teeth for a few, then take it out and stick it in cold water to set the mold. Repeat if it's not a comfortable fit.
Another reason the mouth guard may not feel comfortable is that it is too long. I've had to take an Exacto knife and cut a little off of the ends of mouth guards so I wouldn't feel like I was gagging and choking while I wore it. Even if the mouth guard is a good fit after the boil and bite method, it may still take awhile to get used to wearing.
The main way to get used to a mouth guard is to wear it. Wear it during boxing training at the gym. Wear it for short periods of times while you're at home. If you're sparring, you'll have to wear it.
If any dental work has been done like tooth extractions and teeth being capped for example, it may be a good idea to replace the mouth guard. The old mouth guard may not fit properly after work has been done on the teeth.
Protection is needed for other spots of the body, too, such as the chest.