title: The Effect of Composite Thickness on the Stress Distribution Pattern of Restored Premolar Teeth with Cusp Reduction.
abstract: OBJECTIVE
  Different thicknesses of restorative material can alter the stress distribution pattern in remaining tooth structure. The assumption is that a thicker composite restoration will induce a higher fracture resistance. Therefore, the present study evaluated the effect of composite thickness on stress distribution in a restored premolar with cusp reduction.
  
  
  METHODS
  A 3D solid model of a maxillary second premolar was prepared and meshed. MOD cavities were designed with different cusp reduction thicknesses (0, 0.5, 1, 1.5, 2.5 mm). Cavities were restored with Valux Plus composite. They were loaded with 200 N force on the occlusal surface in the direction of the long axis. Von Mises stresses were evaluated with Abaqus software.
  
  
  RESULTS
  Stress increased from occlusal to gingival and was maximum in the cervical region. The stressed area in the palatal cusp was more than that of the buccal cusp. Increasing the thickness of composite altered the shear stress to compressive stress in the occlusal area of the teeth.
  
  
  CONCLUSIONS
  The model with 2.5 mm cusp reduction exhibited the most even stress distribution.
authors.affiliation: Dental Research Center, Research Institute of Dental Sciences, Dental School, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: Narges
authors.initials: N
authors.lastname: Panahandeh
authors.affiliation: Iranian Center for Endodontic Research, Research Institute of Dental Sciences, Dental School, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: Hassan
authors.initials: H
authors.lastname: Torabzadeh
authors.affiliation: Department of Periodontics, Dental School, Kermanshah University of Medical Sciences, Kermanshah, Iran.
authors.forename: Nargess
authors.initials: N
authors.lastname: Ziaee
authors.affiliation: Department of Prosthodontics and Digital Technology, Stony Brook, NY.
authors.forename: Mina
authors.initials: M
authors.lastname: Mahdian
authors.affiliation: Dental Research Center, Research Institute of Dental Sciences, Dental School, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: Bahman
authors.initials: B
authors.lastname: Tootiaee
authors.affiliation: Preventive Dentistry Research Center, Research Institute of Dental Sciences, Dental School, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: Amir
authors.initials: A
authors.lastname: Ghasemi
mesh_terms: D001641:Bicuspid / Q000502:physiology*; D003481:Cuspid / Q000033:anatomy & histology / Q000502:physiology / Q000601:surgery*; D003731:Dental Caries / Q000601:surgery; D003793:Dental Restoration, Permanent / Q000009:adverse effects; D003799:Dental Stress Analysis; D006801:Humans; D003765:Models, Dental
keywords: Composite onlay; direct restoration; finite element method