title: Radiopacity of Nonmetallic CAD/CAM Restorative Blocks.
abstract: OBJECTIVE
  This study determined the radiopacity of a group of computer-aided design/computer-assisted manufacture blocks using digital radiography and pixel monitoring.
  
  
  METHODS
  Specimens 2.0 ± 0.05-mm thick were cut from nine different blocks. Longitudinal sections of the same thickness were obtained from molar and premolar. Specimens were assigned to one of two groups, and each group was placed on a digital radiograph sensor together with an aluminum step wedge. Following standardized technique, the sensor was exposed and two images were obtained from each group. Images were analyzed using ImageJ software to determine the number of pixels at five different locations for each specimen. Means and standard deviations were calculated and the data statistically analyzed. Radiopacity values were expressed as equivalent of aluminum thickness.
  
  
  RESULTS
  Analysis of variance revealed significant difference in mean pixels among the blocks (P < .001).
  
  
  CONCLUSIONS
  The majority of blocks had radiopacity values that were higher than that of dentin.
authors.forename: Sherif
authors.initials: S
authors.lastname: Hosney
authors.forename: Mohamed
authors.initials: M
authors.lastname: Kandil
authors.forename: Omar
authors.initials: O
authors.lastname: El-Mowafy
mesh_terms: D000535:Aluminum / Q000737:chemistry; D000538:Aluminum Silicates / Q000737:chemistry; D002516:Ceramics / Q000737:chemistry; D003188:Composite Resins / Q000737:chemistry; D017076:Computer-Aided Design; D003287:Contrast Media / Q000737:chemistry*; D003743:Dental Enamel / Q000000981:diagnostic imaging; D003776:Dental Porcelain / Q000737:chemistry*; D003804:Dentin / Q000000981:diagnostic imaging; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D017680:Potassium Compounds / Q000737:chemistry; D019252:Radiography, Dental, Digital / Q000379:methods*; D015040:Zirconium / Q000737:chemistry
chemical_list: D000538:Aluminum Silicates; D003188:Composite Resins; D003287:Contrast Media; D017680:Potassium Compounds; C454801:ProCAD Ceramic; C082340:Vita Mark II; C493120:lithia disilicate; C452079:paradigm MZ100; D003776:Dental Porcelain; C016447:feldspar; C078519:leucite; C023506:Glass ceramics; D015040:Zirconium; D000535:Aluminum; C028541:zirconium oxide