Mouthguards Melbourne do not come in a one-size-fits-all style. The size and form of our teeth, jaw, and mouth varies from person to person. Pre-formed or mouth-formed guards are commonly found at sporting goods and department stores. Pre-formed guards will have the worst fit. To keep them in place, the lips must be closed, making breathing and speech difficult. Mouthguards that are mouth-formed, also known as "boil-and-bite" mouthguards, will fit better and have less bulk. They will not, however, conform to the teeth as closely or as pleasantly as a custom-fitted mouthguard.