Postfabrication thickness of single- and double-layered pressure-formed mouthguards

The thickness of a mouthguard (MG) plays an important role in its primary function of preventing injuries. Multi-layered MGs have recently come into prominent use due to the disadvantages associated with single-layered MGs. Whereas researchers have evaluated the postfabrication thickness of single-layered MGs, the effects of fabrication procedures on multi-layered MGs are unknown. This study aimed to evaluate postfabrication thickness of various single-layered and double-layered pressure-formed MGs.

Mouthguards were fabricated using stone models produced from impressions of a phantom model maxillary arch. A total of 50 MGs were fabricated from ethylene vinyl acetate (EVA) sheets and divided into 10 groups of five according to the sheet(s) used in fabrication. The initial thickness of each sheet was recorded prior to fabrication. Following fabrication, MG thickness was measured at seven sites per MG. Data were analyzed using independent t-tests and one-way anova followed by Tukey's test.

Mean reduction in MG thickness was 36-38% for single-layered MGs and 32-34% for double-layered MGs. Significant differences in thickness were seen between measured sites for all MG groups (P < 0.05). Maximum thinning occurred at the incisal edge of the central incisor, whereas minimum thinning was observed in the molar crown fissure sites for all groups.

Clinicians should take into account the effects of fabrication on MG thickness. A loss of thickness of approximately 50% should be expected in critical areas of both single-layered and double-layered MGs made from EVA.