title: [Effects of different class II cavity designs on stresses in restoration].
abstract: OBJECTIVE
  To assess effects of different class II cavities on stresses of amalgam and composite resin restoration.
  
  
  METHODS
  Five kinds of class II MO cavities were prepared on the first molars of mandibles. The cavities were filled by amalgam and composite resin, respectively. The stresses were analyzed by using three-dimensional finite element method, after vertical and lateral pressures were loaded on the teeth.
  
  
  RESULTS
  The stresses were greater in traditional cavities than those in reformed cavities when 100 N vertical and lateral pressures were loaded on the teeth. But the pressing stress and shearing stress in cavities filled by amalgam were smaller in traditional cavities than those in reformed cavities. The stresses were smaller in cavities filled by resin than those in cavities filled by amalgam significantly, when the cavities were designed with slot retention groove, without slot retention groove and as plate form. The stresses were smaller in two kinds of slot and plate cavities than those in traditional and reformed cavities.
  
  
  CONCLUSIONS
  It is better to design cavity with slot retention groove for amalgam restoration and to design cavity without slot retention groove for composite resin restoration.
authors.affiliation: Department of Oral Medicine, School of Stomatology, Shanghai Second Medical Universiy, Shanghai 200011, China.
authors.forename: Xiao
authors.initials: X
authors.lastname: Xu
authors.forename: Zhe
authors.initials: Z
authors.lastname: Sun
authors.forename: Lan
authors.initials: L
authors.lastname: Tao
authors.forename: Huanguo
authors.initials: H
authors.lastname: Xiong
mesh_terms: D003188:Composite Resins / Q000592:standards; D003723:Dental Amalgam / Q000592:standards; D003737:Dental Cavity Preparation / Q000379:methods*; D003793:Dental Restoration, Permanent / Q000379:methods*; D003799:Dental Stress Analysis / Q000379:methods*; D020342:Finite Element Analysis; D006801:Humans; D008334:Mandible; D003765:Models, Dental; D008963:Molar
chemical_list: D003188:Composite Resins; D003723:Dental Amalgam