title: [Evaluation method with radiographic image quality indicator for internal defects of dental casting metallic restoration].
abstract: OBJECTIVE
  To develop a new kind of dental radiographic image quality indicator (IQI) for internal quality of casting metallic restoration to influence on its usage life.
  
  
  METHODS
  Radiographic image quality indicator method was used to evaluate the depth of the defects region and internal quality of 127 casting metallic restoration and the accuracy was compared with that of conventional callipers method.
  
  
  RESULTS
  In the 127 cases of casting metallic restoration, 9 were found the thickness less than 0.7 mm and the thinnest thickness only 0.2 mm in 26 casting metallic crowns or bridges' occlusal defects region. The data measured by image quality indicator were consistent with those measured by conventional gauging. Two metal inner crowns were found the thickness less than 0.3 mm in 56 porcelain crowns or bridges. The thickness of casting removable partial denture was more than 1.0 mm, but thinner regions were not found. It was found that in a titanium partial denture, the X-ray image of clasp was not uniform and there were internal porosity defects in the clasp.
  
  
  CONCLUSIONS
  Special dental image quality indicator can solve the visual error problems caused by different observing backgrounds and estimate the depth of the defects region in the casting.
authors.affiliation: Dental Material Laboratory, Peking University School and Hospital of Stomatology; National Engineering Laboratory for Digital and Material Technology of Stomatology, Beijing 100081, China.
authors.forename: Y
authors.initials: Y
authors.lastname: Li
authors.affiliation: Dental Material Laboratory, Peking University School and Hospital of Stomatology; National Engineering Laboratory for Digital and Material Technology of Stomatology, Beijing 100081, China.
authors.forename: G
authors.initials: G
authors.lastname: Zheng
authors.affiliation: Dental Material Laboratory, Peking University School and Hospital of Stomatology; National Engineering Laboratory for Digital and Material Technology of Stomatology, Beijing 100081, China.
authors.forename: H
authors.initials: H
authors.lastname: Lin
mesh_terms: D003442:Crowns; D003735:Dental Casting Technique; D003832:Denture, Partial, Removable; D006801:Humans; D016062:Porosity; D019984:Quality Indicators, Health Care; D011861:Radiography, Dental; D014025:Titanium
chemical_list: D014025:Titanium