An In Vitro Comparison of Nickel and Chromium Release from Crown and Loop Space Maintainers

Abstract

Introduction: The oral cavity provides the proper environment for the corrosive interaction between metals and saliva. Hazards of metals include hypersensitivity, dermatitis, etc. Stainless steel has been used routinely as a component of orthodontic appliances. In pediatric dentistry, stainless steel crowns have been used for a long time to restore mutilated primary teeth. Stainless steel crowns comprise base metal alloys that consist primarily of nickel (7-22%), chromium (11.5-27%), and carbon (0.25%). The increasing prevalence of early childhood caries and mutilated dentition compels the pedodontist to use multiple stainless steel crowns and space maintainers. The leaching of nickel and chromium, therefore, is a cause for concern from the crowns, bands, and wires.

Aim: The aim of the study was to compare and evaluate the in vitro biodegradation of nickel and chromium from crowns to loop space maintainers made of crowns from three different companies in artificial saliva.

Materials and methods: About 30 crown and loop space maintainers fabricated from Kids Crowns, 3M ESPE Crowns, and Hu-Friedy Pedo Crowns were used. The number of space maintainers in each group was 1, 2, 3, and 4, respectively. These were placed in separate glass beakers containing 100 mL of artificial saliva at 37°C for 4 weeks. Analysis for nickel and chromium ions was done on days 1, 7, 14, 21, and 28 using an inductively coupled plasma-optical emission spectrophotometer.

Results: The total release of nickel and chromium from all crown and loop space maintainers ranged from 0.0 to 0.10 ppm and 0.0 to 0.019 ppm, respectively.

Statistical analysis used: The data analysis was done using SPSS software, version 16. The comparison was done using a one-way ANOVA test. The post hoc Bonferroni test was used for multiple comparisons.

Conclusion: The overall maximum release of nickel ions was seen from Hu-Friedy Pedo Crowns and was least for Kids Crowns. Chromium showed the maximum release from 3M ESPE Crowns, whereas Kids Crowns and Hu-Friedy Pedo Crowns showed the least. These values were well below the average dietary intake of these metals.

How to cite this article: Kour M, Anand A, Agarwal N, et al. An In Vitro Comparison of Nickel and Chromium Release from Crown and Loop Space Maintainers. Int J Clin Pediatr Dent 2025;18(2):203-209.

Keywords: Artificial saliva; Chromium; Crown and loop space maintainer; Nickel; Spectrophotometer.

Fig. 1

Kids Crowns

Fig. 2

3M ESPE Crowns

Fig. 3

Hu-Friedy Pedo Crowns

Fig. 4

KC Smith 19-gauge wire

Fig. 5

Crown and loop space maintainers (Kids Crowns) immersed in artificial saliva

Fig. 6

Crown and loop space maintainers (3M ESPE Crowns) immersed in artificial saliva

Fig. 7

Crown and loop space maintainers (Hu-Friedy Pedo Crowns) immersed in artificial saliva

Fig. 8

Inductively coupled plasma optical emission spectrophotometer