title: Assessment of nickel release from stainless steel crowns.
abstract: OBJECTIVE
  Adverse effects of dental materials, especially metals, have been an important issue in recent decades.
  
  
  OBJECTIVE
  The purpose of this study was to determine the amount of nickel released from stainless steel crowns in artificial saliva.
  
  
  METHODS
  In this in-vitro study, 270 stainless steel crowns were divided into five groups, each with nine subgroups. Each group (I to V) was comprised of four, five, six, seven and eight crowns, respectively. Each subgroup was placed in a polyethylene jar containing artificial saliva and held in an incubator at 37°C for four weeks. The amount of released nickel was determined on days 1, 7, 14, 21 and 28, using an atomic absorption spectrophotometer. Wilcoxon Signed-Rank and Kruskal-Wallis with Dunn's post hoc tests (SPSS software, v. 18) were used for statistical analysis at a significance level of 0.05.
  
  
  RESULTS
  The mean level of nickel on day 1 was more than that of day 7; this difference was statistically significant for all groups (P < 0.05), except for group II (P = 0.086). Also, the mean difference of released nickel between the groups was significant on day 1 (P = 0.006) and was insignificant on day 7 (P = 0.620). The nickel levels were zero on days 14, 21, and 28.
  
  
  CONCLUSIONS
  The amount of nickel was below the toxic level and did not exceed the dietary intake.
authors: Assistant Professor, Children and Adolescent Health Research Center, Department of Pediatric Dentistry, Faculty of Dentistry, Zahedan University of Medical Sciences, Zahedan, Iran.
authors: Nahid
authors: N
authors: Ramazani
authors: Assistant Professor, Department of Pediatric Dentistry, Faculty of Dentistry, Shahed University, Tehran, Iran.
authors: Rahil
authors: R
authors: Ahmadi
authors: Dentist, Zahedan University of Medical Sciences, Zahedan, Iran.
authors: Mansure
authors: M
authors: Darijani
keywords: Nickel; Saliva; Stainless Steel
references: Biol Trace Elem Res. 2010 Nov;137(2):127-38
references: 20013356
references: Am J Orthod Dentofacial Orthop. 2002 Aug;122(2):217-20
references: 12165778
references: Am J Orthod Dentofacial Orthop. 2010 Jun;137(6):809-15
references: 20685537
references: J Prosthet Dent. 1992 Oct;68(4):692-7
references: 1403951
references: Int Dent J. 1986 Mar;36(1):30-4
references: 3457765
references: Am J Orthod Dentofacial Orthop. 2011 Jun;139(6):730-4
references: 21640878
references: Dent Mater. 2009 Aug;25(8):976-81
references: 19303629
references: J Mater Sci Mater Med. 2010 Feb;21(2):675-83
references: 19826928
references: J Indian Soc Pedod Prev Dent. 2010 Jan-Mar;28(1):6-12
references: 20215665
references: J Clin Pediatr Dent. 2012 Spring;36(3):235-8
references: 22838223
references: Dent Mater. 2008 Feb;24(2):216-20
references: 17544102
references: Dent Mater. 2010 Mar;26(3):249-56
references: 20005564
references: Int J Dent. 2010;2010:326124
references: 21274429
references: Am J Orthod Dentofacial Orthop. 1993 Feb;103(2):115-9
references: 8427215
references: Dermatol Online J. 2011 Mar 15;17(3):12
references: 21426878
references: Braz Oral Res. 2009 Oct-Dec;23(4):399-406
references: 20027447
references: Angle Orthod. 2009 Jan;79(1):102-10
references: 19123703
references: Eur J Orthod. 2006 Jun;28(3):292-7
references: 16415086
references: Anal Chim Acta. 2010 Feb 5;659(1-2):60-7
references: 20103106
references: Orthod Craniofac Res. 2009 Feb;12(1):43-51
references: 19154274