title: The effect of antagonist tooth contact on the biomechanical response of custom-fitted mouthguards.
abstract: OBJECTIVE
  Custom-fitted mouthguards are devices used to prevent dental injuries. The aim of this study was to verify the influence of the antagonist contact on the stresses and strains of the anterior teeth, shock absorption and displacement of EVA custom-fitted mouthguards during a horizontal impact.
  
  
  METHODS
  Finite element models of human maxillary central incisors with and without a mouthguard for different occlusion conditions (with and without antagonist contact) were created based on tomography. A nonlinear dynamic impact analysis using the single-step Houbolt method was performed in which a rigid object hit the model at 1 m s-1. Strain and stress were evaluated by means of Von Mises and Critical modified Von Mises criterion and shock absorption during impact were calculated as well as the mouthguard displacement.
  
  
  RESULTS
  The model without mouthguard and without antagonist contact showed the highest stress and strain values at the enamel and dentin in the tooth crown on impact compared to the model without mouthguard and with antagonist contact. Mouthguard presence reduced the stress and strain values regardless of the occlusion condition. The mouthguard displacement decreased with the mandibular antagonist contact.
  
  
  CONCLUSIONS
  Mouthguards are efficient at decreasing the stress and strain values on the tooth in front of an impact reaching more than 90% of shock absorption. A mouthguard with balanced occlusion and maximum number of contacts with mandibular anterior teeth should be considered because it reduces mouthguard displacement.
authors.affiliation: Department of Operative Dentistry and Dental Materials, School of Dentistry, Federal University of Uberlândia, Minas Gerais, Brazil.
authors.forename: Crisnicaw
authors.identifier: http://orcid.org/0000-0002-8146-9606
authors.initials: C
authors.lastname: Veríssimo
authors.affiliation: Department of Operative Dentistry and Dental Materials, School of Dentistry, Federal University of Uberlândia, Minas Gerais, Brazil.
authors.forename: Aline Aredes
authors.initials: AA
authors.lastname: Bicalho
authors.affiliation: Department of Operative Dentistry and Dental Materials, School of Dentistry, Federal University of Uberlândia, Minas Gerais, Brazil.
authors.forename: Priscilla Barbosa Ferreira
authors.initials: PB
authors.lastname: Soares
authors.affiliation: Department of Restorative Dentistry, College of Dentistry, University of Tennessee Health Science Center, Memphis, TN, USA.
authors.forename: Daranee
authors.initials: D
authors.lastname: Tantbirojn
authors.affiliation: Department of Bioscience Research, College of Dentistry, University of Tennessee Health Science Center, Memphis, TN, USA.
authors.forename: Antheunis
authors.initials: A
authors.lastname: Versluis
authors.affiliation: Department of Operative Dentistry and Dental Materials, School of Dentistry, Federal University of Uberlândia, Minas Gerais, Brazil.
authors.forename: Carlos J
authors.initials: CJ
authors.lastname: Soares
mesh_terms: D001696:Biomechanical Phenomena; D003766:Dental Occlusion; D003799:Dental Stress Analysis; D004867:Equipment Design; D020342:Finite Element Analysis; D006801:Humans; D007180:Incisor / Q000000981:diagnostic imaging; D003765:Models, Dental; D009064:Mouth Protectors; D013314:Stress, Mechanical; D014057:Tomography, X-Ray Computed; D018677:Tooth Injuries / Q000517:prevention & control*
keywords: finite element analysis; mouthguard; strain; stress