title: Energy dispersive x-ray analysis of corrosion products in nondiscolored dentin and a dye-extraction study of Class 2 composite restorations following amalgam removal.
abstract: OBJECTIVE
  To evaluate the effect of corrosion products on the microleakage of composite placed adjacent to nondiscolored dentin after amalgam removal.
  
  
  METHODS
  Sixty Class 2 cavities were prepared on extracted premolars, which were divided into four equal groups according to the manner in which they were restored: group 1, light-cured packable composite (Elite LS) to establish a microleakage baseline; group 2, a high-copper amalgam (World Work) previously stored in 37°C normal saline for 6 months to create amalgam corrosion products; group 3, identical to group 2, but the amalgam was later replaced with composite, leaving the cavity walls intact; and group 4, identical to group 3 except the cavity walls were extended 0.5 mm after amalgam removal prior to insertion of the composite. Groups 1, 3, and 4 were kept in a 37°C normal saline for 1 week. Ten specimens from each of these three groups were randomly selected for dye-extraction testing, while dentin elemental microanalysis of five specimens from all four experimental groups was also conducted. Data were analyzed using ANOVA and the Tukey tests (α = .05).
  
  
  RESULTS
  Corrosion products were not detected in group 4, and no statistically significant difference (P > .05) in microleakage was found between this group and group 1. The highest dye absorbance was associated with group 3 (P < .05).
  
  
  CONCLUSIONS
  After amalgam removal, a 0.5-mm extension of the cavity walls could improve the dentinal marginal seal to replicate that of an initial composite restoration.
authors.affiliation: Operative Dentistry Department, Mashhad Dental School and Dental Materials Research Center, Mashhad University of Medical Sciences, Mashhad, Iran. ghavamnasirim@mums.ac.ir
authors.forename: Marjaneh
authors.initials: M
authors.lastname: Ghavamnasiri
authors.forename: Vahideh
authors.initials: V
authors.lastname: Motamed-Sanaye
authors.forename: Joseph
authors.initials: J
authors.lastname: Chasteen
authors.forename: Hamideh
authors.initials: H
authors.lastname: Ameri
authors.forename: Hila
authors.initials: H
authors.lastname: Hajizadeh
authors.forename: Zahra
authors.initials: Z
authors.lastname: Khashyarmanesh
mesh_terms: D000704:Analysis of Variance; D004396:Coloring Agents; D003188:Composite Resins / Q000032:analysis* / Q000627:therapeutic use; D003343:Corrosion; D003723:Dental Amalgam / Q000737:chemistry; D003736:Dental Cavity Lining / Q000379:methods; D003737:Dental Cavity Preparation / Q000379:methods*; D003763:Dental Leakage / Q000517:prevention & control*; D003793:Dental Restoration, Permanent / Q000379:methods*; D003804:Dentin / Q000737:chemistry*; D006801:Humans; D008855:Microscopy, Electron, Scanning; D019233:Retreatment; D013052:Spectrometry, X-Ray Emission; D018709:Statistics, Nonparametric
chemical_list: D004396:Coloring Agents; D003188:Composite Resins; D003723:Dental Amalgam