Background/Aim The use of custom‐fitted mouthguards can effectively prevent dentoalveolar trauma during sports practice. The aims of this study were to (1) Evaluate the elastic modulus of different EVA commercial brands used for custom‐fitted mouthguards, and (2) Evaluate whether the different EVA brands can influence the stress and strain generated during an impact simulated by three‐dimensional finite element analysis. Methods The elastic modulus of five EVA commercial brands (Essence®, Bio‐Art®, Proform®, PolyShok®, and Erkodent®) were calculated through uniaxial tensile tests. The obtained values were evaluated statistically by Kruskal–Wallis and Dunn's test. A three‐dimensional model of the anterior maxilla was created using the Rhinoceros 5.0. A 3 mm custom‐fitted mouthguard was simulated. The three‐dimensional volumetric mesh was generated using the Patran software (MSC.Software) with isoparametrics, 4‐noded tetrahedral elements, and exported to Marc/Mentat (MSC.Software) as element number 134. A non‐linear dynamic impact analysis was performed in which a rigid object struck the central incisor at a speed of 5 m/s. The stresses were evaluated by the modified von Mises criteria, and the strains were also recorded. Results Statistically significant differences were observed for elastic modulus values (p < .001). Median values and the results of the Dunn's test were Essence® (38.1 A), Bio‐Art® (34.9 AB), Proform® (20.8 BC), PolyShok® (17.4 CD), and Erkodent® (15.0 D) (different capital letters mean statistical differences among the groups). Stresses and strains generated in the model with mouthguards were significantly lower than the model without a mouthguard regardless of the commercial brand. There was no significant difference in the stress and strain on the enamel and dentin with the different EVA brands. The shock absorption ability was high for all the brands (more than 80%). Conclusion The custom‐fitted mouthguards, independently of the commercial brand, reduced stresses and strains during the impact.

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The aim of this study was to evaluate the effect of different die materials used in the indirect resin composite restorative technique on the fracture resistance and failure mode of restored molars and compare it with the direct resin composite restorative technique. Two flexible die silicone materials for dental models (Die Silicone -Voco and Scan die -Yller) and a type IV dental stone material (Fujirock EP -GC) were evaluated. Sixty third molars were selected and divided into four groups: indirect resin composite restoration -Die silicone (IRCR-DS); indirect resin composite restoration -Scan die (IRCR-SD); indirect resin composite restoration -Fujirock EP (IRCR-FR), and direct resin composite restoration (DRCR). Class II MOD cavities were prepared with 5 mm of buccolingual width and depth. The specimens were restored and subjected to an axial compression load until fracture, and the data were analyzed by one-way ANOVA and Tukey's HSD test (α=.05). The fracture mode was classified into restorable and unrestorable fractures. Fracture resistance values were influenced by the die material used for the IRCR fabrication and by the restorative technique (p<.001). Fracture resistance mean values and standard deviation were: