title: [Detection of marginal leakage of Class V restorations in vitro by micro-CT].
abstract: OBJECTIVE
  To evaluate the reliability and superiority of micro-CT in marginal leakage assessment of Class V restorations.
  
  
  METHODS
  Class V preparations with gingival margins in dentin and occlusal in enamel were made in sixteen extracted non-carious human molars and restored with dental bonding agents and composite resin. All teeth were then immersed in 50% ammonia-silver nitrate solution for 12 hours, followed by developing solution for 8 hours. Each restoration was scanned by a micro-CT and silver leakage was measured and three-dimensional image of the silver leakage alone cavity wall were reconstructed. Afterward, all restorations were sectioned and examined for leakage depth using a microscope. The silver leakage depth of each restoration obtained by micro-CT and microscope were compared for equivalency.
  
  
  RESULTS
  The silver leakage depths in gingival wall obtained with micro-CT (0.78 mm) and microscope (0.74 mm) showed no significant difference (P > 0.05), while the judgment of leakage depths in occlusal wall in micro-CT image (0.40 mm) was affected by adjacent enamel structure, giving less leakage depths compared to microscope (0.72 mm)(P < 0.01). The three-dimensional shapes of the microleakages displayed clearly by micro-CT alone wall of Class V restorations were multiform and some leakages showed channels on their way to spreading.
  
  
  CONCLUSIONS
  Micro-CT can detect precisely the silver leakage in the dentin wall of a restoration and display its three-dimensional shape fully. Enamel structure affects the detection of the silver leakage next to it.
authors.affiliation: Department of Dental Materials, College of Stomatology, The Fourth Military Medical University, Xi'an 710032, China.
authors.forename: Lin-juan
authors.initials: LJ
authors.lastname: Gu
authors.forename: Xin-yi
authors.initials: XY
authors.lastname: Zhao
authors.forename: Shi-bao
authors.initials: SB
authors.lastname: Li
mesh_terms: D003737:Dental Cavity Preparation; D003743:Dental Enamel / Q000000981:diagnostic imaging / Q000473:pathology; D003763:Dental Leakage / Q000000981:diagnostic imaging / Q000473:pathology; D003793:Dental Restoration, Permanent / Q000379:methods*; D006801:Humans; D021621:Imaging, Three-Dimensional; D008853:Microscopy; D008964:Molar, Third / Q000000981:diagnostic imaging / Q000473:pathology; D055114:X-Ray Microtomography / Q000379:methods*