title: A three-dimensional finite element study on anterior laminate veneers with different incisal preparations.
abstract: BACKGROUND
  Mechanical properties are important in the long-term success of restorations, but whether different incisal preparations can affect the behavior of veneers remains controversial.
  
  
  OBJECTIVE
  The purpose of this study was to evaluate the influence of different preparation designs on stress distribution in a maxillary incisor restored with veneers and with regard to different restorative materials and loading conditions.
  
  
  METHODS
  Based on the cone beam computed tomography scanning of a maxillary incisor, 3-dimensional finite element models for 2 different designs were developed. A static load of 50 N was applied with angulations of 60 degrees and 125 degrees to the longitudinal axis at the level of the incisal margin, simulating functional movements. Both porcelain laminate veneer and composite resin veneer were considered. The maximum stress values and stress distribution of the veneer, cement layer, and tooth structure were calculated and analyzed.
  
  
  RESULTS
  The maximum stress values in the veneer and tooth were higher with the butt-joint design. Stresses were distributed more uniformly in the cement layer in the palatal chamfer design for porcelain laminate veneers, whereas a better stress distribution under protrusive movement was observed in the butt-joint design for composite resin veneers.
  
  
  CONCLUSIONS
  The palatal chamfer design for porcelain laminate veneers tolerated stress better, whereas the butt-joint design was favored for composite resin veneers, particularly under protrusive movement.
authors: Postgraduate student, Department of Prosthodontics, West China School of Stomatology, Sichuan University, Chengdu, Sichuan, China.
authors: Zhongjie
authors: Z
authors: Li
authors: Associate Professor, Department of Temporomandibular Joint, West China School of Stomatology, Sichuan University, Chengdu, Sichuan, China.
authors: Zheng
authors: Z
authors: Yang
authors: Graduate student, Department of Prosthodontics, West China School of Stomatology, Sichuan University, Chengdu, Sichuan, China.
authors: Ling
authors: L
authors: Zuo
authors: Associate Professor, Department of Prosthodontics, West China School of Stomatology, Sichuan University, Chengdu, Sichuan, China. Electronic address: yukunmeng@hotmail.com.
authors: Yukun
authors: Y
authors: Meng
mesh_terms: D001732:Bite Force; D003188:Composite Resins / Q000737:chemistry; D054893:Cone-Beam Computed Tomography / Q000379:methods; D003738:Dental Cements / Q000737:chemistry; D003764:Dental Materials / Q000737:chemistry; D003776:Dental Porcelain / Q000737:chemistry; D017267:Dental Prosthesis Design; D003801:Dental Veneers; D055119:Elastic Modulus; D004548:Elasticity; D020342:Finite Element Analysis; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D021621:Imaging, Three-Dimensional / Q000379:methods*; D007180:Incisor / Q000000981:diagnostic imaging; D008437:Maxilla / Q000000981:diagnostic imaging; D013314:Stress, Mechanical; D019231:Tooth Preparation, Prosthodontic / Q000379:methods*
chemical_list: D003188:Composite Resins; D003738:Dental Cements; D003764:Dental Materials; D003776:Dental Porcelain