Tooth Discoloration Resulting from a Nano Zinc Oxide-Eugenol Sealer

Introduction: A desirable quality of any endodontic sealer is its ability to be tooth color friendly. Therefore the aim of the present study was to evaluate the tooth discoloration potential of a nano zinc oxide-eugenol (NZOE) sealer. Methods and Materials: In order to evaluate tooth discoloration, the pulp chamber of 60 human maxillary central and lateral incisors were filled with one of the sealers, naming AH-26 (resin-based sealer), Pulpdent sealer (ZOE-based) and a NZOE experimental sealer. Color measurements was assessed at the baseline (before placement of sealers) (T0), 24 h (T1) and 72 h (T2) h, 1-week (T3), and 1-month (T4) after the placement of sealers using the Easy Shade spectrophotometer. Data were analyzed in SPSS software using one-way ANOVA, and repeated measured ANOVA. Results: No significant differences were observed when the paired comparison test was performed (P>0.05). Conclusion: The tested nZOE sealer had similar tooth discoloration potential in comparison with AH-26 and ZOE sealer.Keywords: Nano Particle; Root Canal Sealer; Tooth Discoloration; Spectrophotometry; Zinc-Oxide Eugenol

Assembling of Fluid Filtration System for Quantitative Evaluation of Microleakage in Dental Materials

INTRODUCTION: There are several methods for evaluating microleakage in dentistry, for example dye or bacterial leakage, electro-chemical methods, radioisotope labeling and fluid filtration. The purpose of this study was to assemble the fluid filtration system for quantitative evaluation of microleakage in dental materials. MATERIALS AND METHODS: The roots were connected to a tube filled with an underwater pressure supply. A bubble was introduced into the water to measure endodontic leakage. A digital camera and professional software were utilized to record and measure the bubble displacement. RESULTS: Our system was constructed successfully and functioned correctly. CONCLUSION: In this pilot study we found this system efficient for the evaluation of microleakage of dental materials

Cytotoxicity of a New Nano Zinc-Oxide Eugenol Sealer on Murine Fibroblasts

Introduction: The aim of this study was to evaluate the cytotoxicity of a new nano zinc-oxide eugenol (NZOE) sealer in comparison with AH-26 and Pulpdent root canal sealers. Methods and Materials: The L929 mouse fibroblast cells were cultivated and incubated for 24, 48 or 72 h with different dilutions (1/1, 1/2, 1/4, 1/8, 1/16 and 1/32) of culture media previously exposed to either of the test sealers naming NZOE, AH-26 or Pulpdent. At the end of incubation period, the effect of sealers on cell viability was evaluated using Mosmann’s Tetrazolium Toxicity (MTT) colorimetric assay. The data was compared using the one-way analysis of variance (ANOVA) followed by the Tukey’s post hoc test for multiple comparisons. Results: After 24, 48 or 72 h, both NZOE and Pulpdent sealers inhibited cell viability at 1/1, 1/2 and 1/8 dilutions. Within the 24 and 48 h, the AH-26 sealer reduced the cell viability at all dilutions except the 1/32 solution; however after 72 h even the 1/32 dilution was cytotoxic. Conclusion: The biocompatibility of the nano zinc-oxide eugenol sealer was comparable to Pulpdent sealer and lower than AH-26.Keywords: Cytotoxicity; MTT Assay; Nanoparticles; Root Canal Sealer; Zinc-Oxide Eugenol

In Vitro Cytotoxicity of a New Nano Root Canal Sealer on Human Gingival Fibroblasts

Introduction: The aim of this in vitro study was to evaluate the cytotoxicity of a new nano zinc-oxide eugenol (NZOE) sealer on human gingival fibroblasts (HGFs) compared with Pulpdent (micro-sized ZOE sealer) and AH-26 (resin-based sealer). Methods and Materials: The Pulpdent, AH-26, and NZOE sealers were prepared and exposed to cell culture media immediately after setting, and 24 h and one week after setting. Then, the primary cultured HGFs were incubated for 24 h with different dilutions (1:1 to 1:32) of each sealer extract. Cell viability was evaluated by methyl thiazolyl diphenyl tetrazolium bromide (MTT) assay. The results were compared using two-way analysis of variance followed by Tukey’s post hoc test. The level of significance was set at 0.05. Results: All sealer extracts, up to 32 times dilutions, showed cytotoxicity when exposed to HGF immediately after setting. The extracts obtained 24 h or one week after setting showed lower cytotoxicity than extracts obtained immediately after setting. At all setting times, NZOE showed lower cytotoxicity than Pulpdent and AH-26. While one-week extracts of NZOE had no significant effect on the viability of HGF at dilutions 1:4 to 1:32, both Pulpdent and AH-26 decreased the cell viability at dilutions of 1:4 and 1:8. Conclusion: NZOE exhibited lower cytotoxicity compared to Pulpdent and AH-26 on HGF and has the potential to be considered as a new root canal filling material.Keywords: Cytotoxicity; Human Gingival Fibroblast; MTT assay; Nano; Seale

External root resorption: Arrested or progressing?

External root resorption may be an uncontrolled phenomenon, and the most known interventions have no effect. Even progressive external root resorption may not be controlled by long term Ca(OH)2 therapy. Currently, there are no treatment options for vital tooth that suffer from root resorption. This invasive resorption can lead to extraction of the tooth. The use of new technologies such as low power laser may control this type of resorption

A New Approach to Root Formation

In endodontics, treatment of an open apex tooth with necrotic pulp is a problem. It seems that with promotion of remnants of Hertwig’s epithelial sheath or rest of malassez accompany with a good irrigation of root canal we can expect root formation

Subcutaneous Connective Tissue Reaction to a New Nano Zinc-Oxide Eugenol Sealer in Rat Model

Introduction: The aim of this animal study was to evaluate the histological response of the new nano zinc-oxide eugenol (NZOE) sealer in comparison with Pulp Canal Sealer (ZOE based) and AH-26 (epoxy resin sealer). Methods and Materials: A total of 27 Wistar rats were used. Four polyethylene tubes were implanted in the back of each rat (three tubes containing the test materials and an empty tube as a control). Then, 9 animals were sacrificed at each interval of 15, 30 and 60 days, and the implants were removed with the surrounding tissues.Samples were evaluated for the presence of inflammatory cell (mononuclear cell), vascular changes, fibrous tissue formation and present of giant cell. Comparisons between groups and time-periods were performed using the Kruskal-Wallis and Mann-Whitney U non-parametric tests. The level of significance was set at 0.05. Results: No significant difference was observed in tissue reactions and biocompatibility pattern of three sealers during 3 experimental periods (P<0.05). In all groups the tissue behavior showed tendency to decrease the irritation effect over time. Conclusion: The new nano zinc-oxide eugenol sealer has histocompatibility properties comparable to conventional commercial sealers.Keywords: Biocompatibility; Nanoparticle; Tissue Reaction; Zinc-Oxide Eugeno

Direct Immobilization of Coagulation Factor VIII on Au/Fe3O4 Shell/Core Magnetic Nanoparticles for Analytical Application

Protein-coated nanoparticles have diverse applications in biomedical science. The protein hydrophobic domains or surface electrostatic charge conducts adsorption of proteins to different surfaces. This property can be customized to immobilize specific molecules on solid supports for experimental screenings or purification processes. To develop highly selective affinity ligands—such as aptamers—against specific protein targets, protein-coated magnetic particles have been successfully applied. This approach could be highly efficient in affinity ligand development against coagulation factor VIII.In this study, magnetic nanoparticles were prepared by co-precipitation method and, then, a gold coating was run on the MNPs’ surface. The gold coating could add some attractive specifications to the protein immobilized nanoparticles during the aptamer selection process, such as simultaneous affinity determination of aptameric oligonucleotides by fluorescence-based methods. The gold surface has been indicated as a specific feature for covalent binding to the sulphur functional groups of various molecules. In proteins, sulphur units of cysteine or methionine might be bound covalently to the gold surface. In addition, nonspecific and non-covalent attachment of proteins to the gold particles may be performed. Therefore, a series of samples containing different mass ratios of protein to gold magnetic nanoparticles (GMNPs) were evaluated to find the best conditions for coagulation factor VIII immobilization. The results showed that the best condition for high coating efficiency was 48 h incubation at 4 ºC of protein and GMNPs with a mass ratio of 0.5% in PBS 25mM, with pH=7 as binding buffer.Highlights:Magnetic nanoparticles are the most attractive nanostructures in biomedical and bio-analytical fields.The protein coating on MNPs has been found to have wide clinical and analytical applications.Coagulation factor VIII (FVIII) is a valuable therapeutic human protein in the market.Attachment of a large protein like F VIII to GMNPs is affected by various environmental factors

An In vitro Evaluation of Antimicrobial Efficacy of new Nano-zinc Oxide Eugenol (NZOE)

Introduction: This interventional in-vitro study aimed to evaluate the antimicrobial activity of a new Nano Zinc OxideEugenol (NZOE) sealer in comparison with AH26 and Pulpdent common root canal sealers against endodontic pathogens. Methods: The antimicrobial efficacy of three sealers(NZOE, AH26 and Pulpdent)  against Enterococcus faecalis (ATCC 29212), Escherichia coli (ATCC 25922), Streptococcus mutans (ATCC700610), Candida albicans (ATCC 90028), and Staphylococcus aureus (ATCC 25923)  were evaluated by Direct Contact Test (DCT) at five  different time intervals 0, 2, 14, 48 hours and 7 days. The results were statistically analyzed using SPSS software and Kruskal–Wallis at 5% significance level. Results: All three tested sealers had antimicrobial activity against microorganisms involved in this study. Fresh NZOE sealer eliminated all microorganisms tested, except the strain of E. faecalis colony which was reached to zero after 2 hours. However, AH26 and Pulpdent failed to completely kill all of the E. faecalis colony during the entire observation period. Also, NZOE showed a significant antimicrobial action (