title: Does magnetic resonance imaging affect the microleakage of amalgam restorations?
abstract: BACKGROUND
  The effect of MRI on microleakage of amalgam restorations is an important health issue that should be considered. If MRI application causes increase of microleakage, amalgam fillings should be reassessed after MRI and replaced if necessary.
  
  
  OBJECTIVE
  The aim of this study is to compare the effect of magnetic resonance imaging (MRI) on microleakage of class II bonded amalgam versus classical amalgam restorations.
  
  
  METHODS
  Class II cavities (3 mm width × 1.5 mm depth) with gingival margins ending 1 mm below the cementoenamel junction (CEJ) were prepared in 40 permanent molar teeth. The teeth were randomly divided into four groups. Cavities in the first and second groups were restored with dentin adhesive and amalgam (bonded amalgam), and those in the third and fourth groups with amalgam only. MRI was performed with the teeth specimens from the first and third groups. All specimens were then thermocycled at 5° to 55° C with a 30-second dwell time for 1000 cycles. The samples were then immersed in 0.5% methylene blue dye for 24 hours and sectioned longitudinally. Dye penetration at the occlusal and gingival margins was quantified by 15× stereomicroscopy. IBM SPSS Statistics ver. 21.0 (IBM Corp., Released 2012., IBM SPSS Statistics for Windows, Armonk, NY: IBM Corp.) and MS-Excel 2007 programs were used for statistical analyses and calculations. "nparLD" module was used for F2_LD_F1 design analysis at R program. P<0.05 was considered statistically significant.
  
  
  RESULTS
  In teeth with amalgam filling, there were no significant differences of occlusal and gingival surface microleakage after MRI exposure. Occlusal and gingival surface microleakages were also similar with and without MRI in teeth with bonded amalgam filling.
  
  
  CONCLUSIONS
  The results of this study suggest that MRI does not increase microleakage of amalgam restorations.
authors.affiliation: Department of Pediatric Dentistry, Gulhane Medical Academy, Ankara, Turkey.
authors.forename: Ozlem Marti
authors.initials: OM
authors.lastname: Akgun
authors.affiliation: Department of Pediatric Dentistry, Gulhane Medical Academy, Ankara, Turkey.
authors.forename: Gunseli Guven
authors.initials: GG
authors.lastname: Polat
authors.affiliation: Department of Radiology, Izmir Mevki Military Hospital, Izmir, Turkey.
authors.forename: Ahmet
authors.initials: A
authors.lastname: Turan Illca
authors.affiliation: Department of Pediatric Dentistry, Gulhane Medical Academy, Ankara, Turkey.
authors.forename: Ceren
authors.initials: C
authors.lastname: Yildirim
authors.affiliation: Department of Biostatistics and Medical Informatics, Yildirim Beyazit University, Ankara, Turkey.
authors.forename: Pervin
authors.initials: P
authors.lastname: Demir
authors.affiliation: Department of Pediatric Dentistry, Gulhane Medical Academy, Ankara, Turkey.
authors.forename: Feridun
authors.initials: F
authors.lastname: Basak
keywords: Dental Amalgam; Magnetic Resonance Imaging; Microleakage