title: Modifying the biomechanical response of mouthguards with hard inserts: A finite element study.
abstract: OBJECTIVE
  To investigate the influence of a high elastic modulus material insert on the stress, shock absorption and displacement of mouthguards.
  
  
  METHODS
  Finite element models of a human maxillary central incisor with and without mouthguard were created based on cross-sectional CT-tomography. The mouthguard models had four designs: without insert, and middle, external, or palatal hard insert. The hard inserts had a relatively high elastic modulus when compared to the elastic modulus of ethylene vinyl acetate (EVA): 15 GPa versus 18 MPa. A non-linear dynamic impact analysis was performed in which a heavy rigid object hit the model at 1 m/s. Strain and stress (von Mises and critical modified von Mises) distributions and shock absorption during impact were calculated as well as the mouthguard displacement.
  
  
  RESULTS
  The model without mouthguard had the highest stress values at the enamel and dentin structures in the tooth crown during the impact. It was concluded that the use of a mouthguard promoted lower stress and strain values in the teeth during impact. Hard insertion in the middle and palatal side of the mouthguard improved biomechanical response by lowering stress and strain on the teeth and lowering mouthguard displacement.
authors.forename: Crisnicaw
authors.initials: C
authors.lastname: Verissimo
authors.forename: Paulo César Freitas
authors.initials: PC
authors.lastname: Santos-Filho
authors.forename: Daranee
authors.initials: D
authors.lastname: Tantbirojn
authors.forename: Antheunis
authors.initials: A
authors.lastname: Versluis
authors.forename: Carlos José
authors.initials: CJ
authors.lastname: Soares
mesh_terms: D019412:Anatomy, Cross-Sectional; D001696:Biomechanical Phenomena; D003198:Computer Simulation; D003743:Dental Enamel / Q000502:physiology; D003804:Dentin / Q000502:physiology; D055119:Elastic Modulus; D004867:Equipment Design; D020342:Finite Element Analysis; D006244:Hardness; D006801:Humans; D007180:Incisor / Q000502:physiology; D008437:Maxilla / Q000502:physiology; D008954:Models, Biological; D009064:Mouth Protectors; D017711:Nonlinear Dynamics; D011145:Polyvinyls / Q000737:chemistry; D013314:Stress, Mechanical; D013499:Surface Properties; D014057:Tomography, X-Ray Computed / Q000379:methods; D019228:Tooth Crown / Q000502:physiology
chemical_list: D011145:Polyvinyls; C016438:ethylenevinylacetate copolymer