title: Accuracy of digital subtraction radiography in combination with a contrast media in assessment of proximal caries depth.
abstract: OBJECTIVE
  Radiography is used to diagnose the demineralization process and carious lesions; however, conventional radiography and direct digital images do not show these lesions when the amount of demineralization is less than 40%. Digital subtraction radiography has recently been used to improve the diagnostic quality of these le-sions. The purpose of this study was to compare the caries depth estimated by digital subtraction radiog-raphy in combination with barium sulfate in diag-nosing proximal dental caries with histopathologic evaluation.
  
  
  METHODS
  In this study 30 molars and premolars (24 demineralized lesions with cavity, 8 without cavity) were studied. Direct digital images were taken (kVp: 68, mA: 8; t: 0.12 for premolars and t: 0.16 for molars) whereas the position of X-ray tube and CCD receptor and teeth was fixed. To prepare the second images 135 gr/L barium sulfate was used. The images obtained with the same exposure and geometry and then subtracted. The depth of the lesions in direct digital and subtracted images were assessed and compared with the depth measured in histopathologic assessments.
  
  
  RESULTS
  The mean depths (± SD) of the lesions were 1.80 ± 0.77 mm in direct digital radiography, 2.32 ± 0.76 mm in subtracted images after barium sulfate treatment, and 2.51 ± 0.43 mm in histopathologic sections. The statistical difference between direct digital radiography and the other methods was significant (P < 0.05). However, the differences were not statistically significant between subtracted images and histopathologic sections. The average intra-class correlation coefficient was 0.7241 (CI: 95%).
  
  
  CONCLUSIONS
  The present study has demonstrated that digital subtraction radiography images have the potential to measure the depth of proximal caries with no significant difference with histopathologic evaluation.
authors.affiliation: Assistant Professor, Department of Oral and Maxillofacial Radiology, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: Solmaz
authors.initials: S
authors.lastname: Valizadeh
authors.forename: Sara
authors.initials: S
authors.lastname: Ehsani
authors.forename: Farzad
authors.initials: F
authors.lastname: Esmaeili
authors.forename: Mohammad Amin
authors.initials: MA
authors.lastname: Tavakoli
keywords: Barium sulfate; dental caries; digital subtraction radiography