title: Fracture resistance and marginal discrepancy of porcelain laminate veneers influenced by preparation design and restorative material in vitro.
abstract: OBJECTIVE
  The purpose of this investigation is to evaluate marginal discrepancy and fracture resistance of two veneering materials using two preparation designs.
  
  
  METHODS
  Two veneer preparation designs (full and traditional) were restored with leucite-reinforced ceramic (ProCAD, Ivoclar Vivadent, Amherst, NY) milled by CAD/CAM (Cerec 3D milling system, Serona Dental Systems), and conventional sintered feldspathic porcelain (Noritake Super Porcelain EX3, Noritake Dental Supply Co). Forty-eight specimens were analysed with a sample size of n=12 per group. The thickness of each veneer was measured on four specific surfaces. Marginal discrepancy was evaluated with a replica technique and cross-sectional view using a digital microscope. The fracture resistance of veneers cemented on standardised composite resin dies was evaluated using a universal testing machine. Results were analysed with ANOVA, Tukey-Kramer post hoc testing, and linear regression.
  
  
  RESULTS
  The results of this investigation revealed no correlation between the thickness and marginal discrepancy of the veneers. The full preparation design with ProCAD and the traditional preparation design with feldspathic porcelain manifested smaller gap. Fracture resistance was decreased for the full preparation design with feldspathic porcelain.
  
  
  CONCLUSIONS
  In terms of marginal discrepancy and fracture resistance, the most favourable combination was a traditional veneer preparation design with conventional sintered feldspathic porcelain. For the full veneer preparation, a stronger ceramic material such as ProCAD is suggested.
authors.affiliation: Department of General Dentistry, Chang Gung Memorial Hospital, Taipei, Taiwan.
authors.forename: Tai-Min
authors.initials: TM
authors.lastname: Lin
authors.forename: Perng-Ru
authors.initials: PR
authors.lastname: Liu
authors.forename: Lance C
authors.initials: LC
authors.lastname: Ramp
authors.forename: Milton E
authors.initials: ME
authors.lastname: Essig
authors.forename: Daniel A
authors.initials: DA
authors.lastname: Givan
authors.forename: Yu-Hwa
authors.initials: YH
authors.lastname: Pan
mesh_terms: D000538:Aluminum Silicates / Q000737:chemistry; D002484:Cementation; D017076:Computer-Aided Design; D018772:Dental Marginal Adaptation; D003776:Dental Porcelain / Q000737:chemistry*; D017267:Dental Prosthesis Design; D003799:Dental Stress Analysis / Q000295:instrumentation; D003801:Dental Veneers; D006801:Humans; D008422:Materials Testing; D008853:Microscopy; D017680:Potassium Compounds / Q000737:chemistry; D016628:Replica Techniques; D013314:Stress, Mechanical; D013499:Surface Properties; D013696:Temperature; D013997:Time Factors; D019231:Tooth Preparation, Prosthodontic / Q000379:methods; D014867:Water / Q000737:chemistry
chemical_list: D000538:Aluminum Silicates; D017680:Potassium Compounds; C454801:ProCAD Ceramic; D014867:Water; D003776:Dental Porcelain; C016447:feldspar; C078519:leucite