Effectiveness of hard inserts in sports mouthguards: a systematic review

Objectives To improve the protective capacity of conventional ethylene-vinyl acetate mouthguards, some authors have suggested reinforcement with a hard material to distribute impact energy more widely. The research question for this systematic review was: 'does the inclusion of a hard insert in mouthguards improve the protection of anterior teeth from a direct blow?'Data sources Three bibliographic databases (PubMed/Medline, Ovid/Embase and the Cochrane CENTRAL databases) were searched up to 20 February 2021. Additional searches included hand searching of key articles and journals.Data selection A systematic search of the literature included studies where the intervention was the incorporation of hard material into sports mouthguards and where the comparator was conventional mouthguard material. Eligibility required the use of anatomical specimens or anatomical analogues which included or represented anterior maxillary teeth. Twelve eligible publications were identified.Data extraction Data extraction was first carried out independently by two reviewers. Discrepancies were resolved by discussion.Data synthesis Results of individual studies were conflicting and methodological diversity created difficulty in making a synthesis of results. All studies employed low-energy impacts that did not represent the potentially high-energy impacts encountered in sport.Conclusion The efficacy of hard inserts in sports mouthguards has not been demonstrated.