In Vitro and In Vivo Toxicity Evaluation of Colloidal Silver Nanoparticles Used in Endodontic Treatments.
INTRODUCTION
Silver nanoparticles have been used for different purposes in dentistry, including endodontic treatments. The aim of this study was to determine the cytotoxicity of different types of silver nanoparticles on mouse fibroblast cell line L929 and the reaction of subcutaneous connective tissue of Wistar rats to these nanoparticles.


METHODS
Silver nanoparticles of an average size of 5 nm were synthesized with ammonia (SNA) or polyvinylpyrrolidone (SNP). L929 was exposed to SNA and SNP (0.1-100 μg/mL), and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide and enzyme-linked immunosorbent assays were performed after 6, 24, and 48 hours. Culture medium was used as the control. Sixteen rats received, individually, 3 polyethylene tubes filled with a fibrin sponge embedded in 100 μL SNA or SNP (1 μg/mL). A fibrin sponge with no embedding was the control. Tissue reaction was performed qualitatively and quantitatively after 7, 15, 30, and 90 days of implantation in the dorsal connective tissue of Wistar rats.


RESULTS
SNA and SNP were cytotoxic to L929 in higher concentrations, with SNA significantly more toxic than SNP. SNA and SNP did not induce significant interleukin-1β and interleukin-6 production. The release of stem cell factor by L929 increased 48 hours after the treatment with SNP at 5 μg/mL. Histologic examination showed that the inflammatory responses caused by SNA and SNP at 1 μg/mL were similar to the control in all experimental periods.


CONCLUSIONS
It was concluded that SNA and SNP were not cytotoxic at 25 μg/mL or lower concentrations. However, for safe clinical use, further studies establishing others points of its toxicologic profile are recommended.
['Takamiya|Aline Satie|AS|', 'Monteiro|Douglas Roberto|DR|', 'Bernabé|Daniel Galera|DG|', 'Gorup|Luiz Fernando|LF|', 'Camargo|Emerson Rodrigues|ER|', 'Gomes-Filho|João Eduardo|JE|', 'Oliveira|Sandra Helena Penha|SH|', 'Barbosa|Debora Barros|DB|']
D000641:Ammonia D000818:Animals D002460:Cell Line D002470:Cell Survival D003238:Connective Tissue D003764:Dental Materials D004305:Dose-Response Relationship, Drug D004797:Enzyme-Linked Immunosorbent Assay D005337:Fibrin D005347:Fibroblasts D007249:Inflammation D053583:Interleukin-1beta D015850:Interleukin-6 D008297:Male D008422:Materials Testing D053768:Metal Nanoparticles D051379:Mice D046529:Microscopy, Electron, Transmission D009504:Neutrophils D010316:Particle Size D011161:Porifera D011205:Povidone D051381:Rats D017208:Rats, Wistar D012834:Silver D019089:Stem Cell Factor D040521:Subcutaneous Tissue D013778:Tetrazolium Salts D013844:Thiazoles D013997:Time Factors D018675:Toxicity Tests
toxicity silver nanoparticles Biocompatibility endodontic materials inflammation