Stock. Stock mouthguards are preformed mouthguards that can be found over the counter, and although they come in a variety of sizes, they are not molded to your mouth, so they can be bulky and fit poorly, making it difficult to talk and breathe. Stock mouthguards are the most inexpensive but are best suited for occasional use.
Boil-and-bite. Boil-and-bite mouthguards are made of a thermoplastic material that can be softened and shaped to fit your mouth by “boiling” the mouthguard and then “biting” into it. This will provide a somewhat better fit than stock mouthguards, but not as snug as a custom-fitted one. Slightly more expensive, these mouthguards can also be found off the shelf and are more suitable for regular use in sports or other high-impact activities.
Custom-fitted. These mouthguards, available only from a dental or orthodontic professional, are just that—custom-fitted to your mouth. They are made with a mold of your teeth for a mouthguard that fits the structure of your mouth and teeth perfectly. They do cost more, but they offer the best fit and protection and can be designed to fit your specific need, whether that’s protection from injury or for night use to prevent teeth grinding and clenching.