title: [Preliminary analysis about influence of porcelain thickness on interfacial crack of PFM].
abstract: OBJECTIVE
  This study was about the influence of porcelain thickness on crack at interface.
  
  
  METHODS
  The effect of porcelain thickness on the flaw at the interface between porcelain and metal was studied in three groups with porcelain thickness of 0.5 mm, 1.5 mm and 2.5 mm (metal thickness of 0.5 mm) by means of moire interferometre and interfacial fracture mechanics. The parameter Jc was compared among the three groups and the growing of the flaw was observed.
  
  
  RESULTS
  Jc and the extreme strength of group with porcelain thickness of 0.5 mm (2.813 N/m and 9.979 N) were lower than those of the groups with porcelain thickness of 1.5 mm and 2.5 mm (5.395 N/m, 19.134 N and 5.429 N/m, 19.256 N). Flaws extend along the interface in the groups with porcelain thickness of 1.5 mm and 0.5 mm.
  
  
  CONCLUSIONS
  (1) Fracture resistance of the interface in the groups with porcelain thickness of 1.5 mm and 2.5 mm is similar and it decreases in the group with 0.5 mm thick porcelain. (2) When porcelain is 1.5 mm or 0.5 mm thick, flaws will extend along the interface. When porcelain is 2.5 mm thick, flaws will extend into the porcelain layer.
authors.affiliation: Department of Prosthodontics, School of Stomatology, Shanghai Second Medical University, Shanghai 200011, China.
authors.forename: Ziyuan
authors.initials: Z
authors.lastname: Zhu
authors.forename: Baowei
authors.initials: B
authors.lastname: Zhang
authors.forename: Xiuyin
authors.initials: X
authors.lastname: Zhang
authors.forename: Kan
authors.initials: K
authors.lastname: Xu
authors.forename: Ruhua
authors.initials: R
authors.lastname: Fang
authors.forename: Dongmei
authors.initials: D
authors.lastname: Wang
mesh_terms: D003776:Dental Porcelain; D003799:Dental Stress Analysis; D006801:Humans
chemical_list: D003776:Dental Porcelain