A mouthguard is a protective device that can buffer impact force and reduce the risk of maxillofacial trauma. A custom-made mouthguard enjoys great popularity owing to its superior comfort and stress dispersion effect. A mouthguard sheet is heated, then becomes soft, and stretches during fabrication; this process makes the mouthguard thinner and less effective. Accordingly, we will make a brief review of the factors(including hardness, shape, and surface design of sheets; thickness and position angle of work model; laminating methods; and shape of holding tray, holding condition, and distance between holding tray and work model) that affect the thickness variation of the incisal region of a custom-made mouthguard.
