Evaluation of a dentoalveolar model for testing mouthguards: stress and strain analyses.

BACKGROUND/AIM: Custom-fitted mouthguards are devices used to decrease the likelihood of dental trauma. The aim of this study was to develop an experimental bovine dentoalveolar model with periodontal ligament to evaluate mouthguard shock absorption, and impact strain and stress behavior. METHODS: A pendulum impact device was developed to perform the impact tests with two different impact materials (steel ball and baseball). Five bovine jaws were selected with standard age and dimensions. Six-mm mouthguards were made for the impact tests. The jaws were fixed in a pendulum device and impacts were performed from 90, 60, and 45° angles, with and without mouthguard. Strain gauges were attached at the palatal surface of the impacted tooth. The strain and shock absorption of the mouthguards was calculated and data were analyzed with 3-way anova and Tukey's test (α = 0.05). Two-dimensional finite element models were created based on the cross-section of the bovine dentoalveolar model used in the experiment. A nonlinear dynamic impact analysis was performed to evaluate the strain and stress distributions. RESULTS: Without mouthguards, the increase in impact angulation significantly increased strains and stresses. Mouthguards reduced strain and stress values. CONCLUSIONS: Impact velocity, impact object (steel ball or baseball), and mouthguard presence affected the impact stresses and strains in a bovine dentoalveolar model. Experimental strain measurements and finite element models predicted similar behavior; therefore, both methodologies are suitable for evaluating the biomechanical performance of mouthguards.

Custom-Fitted EVA Mouthguards: what is the ideal thickness? a dynamic finite element impact study.

BACKGROUND/AIM: The aim of this study was to evaluate the tooth stresses and strains, shock absorption, and displacement during impact of custom-fitted mouthguards with different thicknesses. METHODS: Six bar-shaped specimens of the EVA were made and subjected to tensile test for elastic modulus assessment. Two-dimensional plane-strain models of a human maxillary central incisor, periodontal ligament, bone support, soft tissue, and mouthguard (MTG) were created. The mouthguards were modeled in five different thicknesses (2, 3, 4, 5, and 6 mm). One model was created without mouthguard. A nonlinear dynamic impact analysis was performed in which a rigid object hit the model at 1 m s(-1). Strain and stress (von Mises and Critical modified von Mises) distributions were evaluated, and the displacement of the mouthguard with respect to the tooth was calculated. RESULTS: The mean [SD] for the EVA elastic modulus was 18.075 [0.457] MPa. The model without mouthguard showed the highest stress values at the enamel and dentin structures in the tooth crown during the impact. For the MTG models, the location of the stress concentrations changed to the root, regardless of the MTG thickness, but maximum stresses in the enamel and dentin were lower compared with the model without MTG. Increasing the mouthguard thickness did not notably decrease the stress-strain values. CONCLUSION: It was concluded that the use of a mouthguard promoted lower stresses and strains in teeth during an impact with a rigid object. There was no substantial difference in peak stresses and strains and in shock absorption among the different mouthguard thicknesses.

Protetores bucais personalizados: aspectos clínicos e biomecânicos / Custom-Fitted mouthguards: clinical and biomechanical aspects

Protetores bucais são dispositivos utilizados com o objetivo de absorver as tensões geradas pelo impacto e prevenção de traumatismos dentoalveolares durante a prática esportiva. Este artigo apresenta, por meio de associação de evidência científica e relato de caso, uma abordagem crítica dos parâmetros envolvidos na confecção de protetor bucal personalizado em etileno vinil acetato (EVA) e funções durante o uso. A associação de ensaios laboratoriais e computacionais como método de elementos finitos é essencial para o entendimento do comportamento biomecânico dos protetores bucais. O presente estudo apresenta evidência científica sobre a eficiência de protetores bucais personalizados na absorção de choques e prevenção de traumas...

Mouthguards are devices used to absorb stresses generated by the impact and to prevent dental trauma during sport practice. This article presents the association of scientific evidence and a case report on critical parameters for the fabrication of a Ethylene Vinyl Acetate (EVA) custom-fitted mouthguard, and function during its use. The association of laboratory and computational tests such as the finite element method is essential to understand the biomechanical behavior of mouthguards. This study presents scientific evidence that proves the efficiency of EVA custom-fitted mouthguards os shock absorption and prevention of dental trauma...