In May 2019 researchers from the USA published their review of the medical scientific literature to assess the effectiveness of mouthguards to prevent sports related injuries to the mouth, jaws and face and concussions. A total of 26 studies were included in the review. An analysis of these studies revealed a variety of study designs with multiple methodological weaknesses, different types of mouthguards being used and a wide variety of injury definitions. However, despite this results showed that mouthguards reduced the overall risk of injuries involving the mouth, jaws and face whereas the effect of mouthguards on the incidence of concussion was only modest.
Knapik JJ et al. Effectiveness of Mouthguards for the Prevention of Orofacial Injuries and Concussions in Sports: Systematic Review and Meta-Analysis. Sports Med. 2019 May 30. [Epub ahead of print]