Cytotoxicity and genotoxicity of orthodontic bands with or without silver soldered joints.
Stainless steel bands, with or without silver soldered joints, are routinely used in orthodontics. However, little is known about the toxic biological effects of these appliances. The aims of this study were to evaluate the cytotoxic, cytostatic, genotoxic and DNA damage-inducing effects of non-soldered bands (NSB) and silver soldered bands (SSB) on the HepG2 and HOK cell lines and to quantify the amount of ions released by the bands. The 24-h metallic eluates of NSBs and SSBs were quantified by atomic absorption spectrophotometry. An MTT reduction assay was performed to evaluate the cytotoxicity, alkaline and modified comet assays were employed to measure genotoxicity and oxidative DNA damage effects, and cytokinesis-block micronucleus cytome (CBMN-Cyt) assays were used to verify DNA damage, cytostasis and cytotoxicity. Ag, Cd, Cr, Cu and Zn were detected in SSB medium samples, and Fe and Ni were detected in both the SSB and NSB medium samples. The SSB group induced stronger cytotoxic effects than the NSB group in both evaluated cell lines. NSB and SSB induced genotoxicity as evaluated by comet assays; stronger effects were observed in the SSB group. Both groups induced similar increases in the number of oxidative DNA lesions, as detected by the FPG and Endo III enzymes. Nucleoplasmic bridges, biomarkers of DNA misrepair and/or telomere end fusions, were significantly elevated in the SSB group. The SSB eluates showed higher amounts of Ni and Fe than NSB, and all the quantified ions were detected in SSB eluates, including Cd. The SSB eluates were more cytotoxic and genotoxic than the NSB samples. Based on these results, we propose that other brands, materials and techniques should be further investigated for the future manufacture of orthodontic appliances.
Department of Orthodontics, Pontifical Catholic University of Rio Grande do Sul, Porto Alegre, RS, Brazil. Electronic address: tatianasiqueiragoncalves@gmail.com.
Tatiana Siqueira
TS
Gonçalves
Department of Orthodontics, Pontifical Catholic University of Rio Grande do Sul, Porto Alegre, RS, Brazil. Electronic address: luciane.menezes@pucrs.br.
Luciane Macedo de
LM
Menezes
Instituto de Educação para Pesquisa, Desenvolvimento e Inovação Tecnológica - ROYAL Unidade GENOTOX - ROYAL/Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil. Electronic address: cristiano.trindade17@gmail.com.
Cristiano
C
Trindade
Instituto de Educação para Pesquisa, Desenvolvimento e Inovação Tecnológica - ROYAL Unidade GENOTOX - ROYAL/Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil. Electronic address: mirianamachado@gmail.com.
Miriana da Silva
Mda S
Machado
Commonwealth Scientific and Industrial Research Organisation, Animal, Food and Health Sciences, Adelaide, SA, Australia. Electronic address: Philip.Thomas@csiro.au.
Philip
P
Thomas
Commonwealth Scientific and Industrial Research Organisation, Animal, Food and Health Sciences, Adelaide, SA, Australia. Electronic address: Michael.Fenech@csiro.au.
Michael
M
Fenech
Instituto de Educação para Pesquisa, Desenvolvimento e Inovação Tecnológica - ROYAL Unidade GENOTOX - ROYAL/Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil; Instituto de Biotecnologia - Universidade de Caxias do Sul; Laboratório de Reparação de DNA em Eucariotos, Departamento de Biofísica/Centro de Biotecnologia, UFRGS, Porto Alegre, RS, Brazil. Electronic address: pegas.henriques@gmail.com.
João Antonio Pêgas
JA
Henriques
D002412:Cations; D018929:Cell Culture Techniques; D002470:Cell Survival / Q000187:drug effects; D020552:Comet Assay; D003470:Culture Media; D004249:DNA Damage; D056945:Hep G2 Cells; D006801:Humans; D015603:Keratinocytes / Q000187:drug effects / Q000473:pathology; D048629:Micronuclei, Chromosome-Defective / Q000139:chemically induced*; D015162:Micronucleus Tests; D009967:Orthodontic Appliances; D012834:Silver / Q000633:toxicity*; D013193:Stainless Steel / Q000633:toxicity*; D018675:Toxicity Tests / Q000379:methods
D002412:Cations; D003470:Culture Media; D013193:Stainless Steel; D012834:Silver
Cell viability; Genotoxicity; Metal ion toxicity; Mutagenicity; Orthodontics