Mouth Formed Protectors or "Boil-and-Bite"
There are two types of mouth-formed protectors: the shell-liner and the thermoplastic mouthguard. The shell-liner type is made of a preformed shell with a liner of plastic acrylic or silicone rubber. The lining material is placed in the player’s mouth and molds to the teeth and then is allowed to set. The preformed, thermoplastic type also has a lining that is immersed in boiling water for 10-45 seconds, transferred to cold water and then adapted to the teeth (also known as “boil-and-bite” guard). This mouthguard seems to be the most popular of the three types and is used by more than 90% of the athletic population.24 In 2015, the ADA gave its first Seal of Acceptance for a sports mouthguard. The mouthguard was created by a New Jersey dentist/pharmacist and an associate professor of chemistry at Rutgers University.52 Currently the ADA has listed only one mouthguard on the ADA Seal Products website -- the Game On Mouthguard by Dental Choice Holdings, LLC. The ADA states that it received acceptance due to meeting the safety and efficacy requirements. They indicate when use as directed, it can help protect teeth from impact trauma.
Figure 8. Boil-and-Bite Mouthguards.