| Part1:Cytotoxicity of MetaSEAL and RealSeal SE to MC3T3-E1osteoblast cell lineObjective:The cytotoxicity of two new self-adhesive endodontic sealers MetaSEAL and RealSeal SE to mice MC3T3-E1osteoblast cell line were evalutated and compared with a traditional epoxy resin?based sealer AH Plus.Material&Methods:The sterile cylindrical Teflon tubes were filled with three tested sealers and then placed into a light-resistant container for7days to allow the sealers set completely. A series of concentrations (100%,50%,25%and12.5%) of elutes of three sealers were exposed to MC3T3-E1osteoblast cell cultures for24hours to evaluate the cell survival rates. The cell viability of osteoblast was evaluated by Cell Counting Kit-8assay. The data were analysed for statistically significant differences by one-way ANOVA analysis and Bonferroni multiple comparison (?=0.05). The effects of concentrations were analysed by t-test (?=0.05).Result:The cell viabilities of MetaSEAL in different diluted concentrations were significantly lower than those of RealSeal SE and AH Plus (P<0.05). The cell viabilities of RealSeal SE were significantly lower than those of AH Plus in100%,50%,25%concentrations (P<0.05), whereas silimlar to that of AH Plus in12.5%concentration. AH Plus sealer showed nontoxicity to MC3T3-El osteoblastic cells with the cell survival rates similar to those of negative control in100%,50%concentrations and significantly lower than those of control group in25%,12.5%concentrations (P<0.05). The cell viability of RealSeal SE in low concentration (25%>12.5%) group was significantly higher than the high concentrations (100%, 50%) group (P<0.05), whereas that of MetaSEAL and AH Plus between the high and low concentrations had no significant difference.Conclusions:With the limitation of this study, MetaSEAL sealer showed severe cytotoxicity to MC3T3-El osteoblastic cells, whereas AH Plus exhibited nontoxicity. RealSeal SE demonstrated severe cytotoxicity when osteoblastic cells exposed to higher concentrations but nontoxicity in lower exposed concentrations. Part2:Push-out Bond Strength of MetaSEAL and RealSeal SE to Root DentinObjective:The adhesive strength of two self-adhesive methacrylate resin-based sealers (MetaSEAL and RealSeal SE) was evaluated and compared to that of AH Plus.Material&Methods:A total of36extracted human single-rooted teeth were used. A0.9-mm thick longitudinal tooth slice was prepared from each tooth. Standardized simulated canal spaces of uniform dimensions were prepared in the middle of radicular dentin. Each tooth slice was treated with5.25%sodium hypochlorite (NaOCl) and17%EDTA. Then the slices were randomly divided into three groups. For each sealer,12tooth slabs were used. The sealers were dispensed into the simulated canal spaces respectively. In each group, there were10slabs with20simulated canal spaces (n=20) used for push-out testing. The data were collected and analysed for statistically significant differences by Kruskal-Wallis analysis and Mann-Whitney Post hoc comparisons (a=0.05). The failure modes were investigated under a stereomicroscope. The ultrastructures of fractured sealer-dentin interfaces were investigated under a scanning electron microscope (SEM). The balance of2slabs in each group were observed for ultrastructure of resin tags.Results:1> The results indicated MetaSEAL had the highest push-out test values (12.01±4.66MPa)(P<O.05) among the three sealers. Between RealSeal SE (5.43±3.68MPa) and AH Plus (7.34±2.83MPa), there was no statistically significant difference in the push-out strength. Mixed failures were predominated in MetaSEAL and AH Plus groups, while adhesive failures were frequently found in RealSeal SE. 2, Various amounts of sealer remnants and patent tubular orifices could be seen along the simulated root canal dentinal walls in all specimens under a SEM. Some resin tags had been sheared off but remained in some dentinal tubules.The residual sealant and sheared-off tags were more frequencely left on dentin wall in MetaSEAL group and those of RealSeal SE group were the least. The tags formation and presence of interfacial separation along the dentin-sealer interface also could be obsevered in all groups. In specimens filled with MetaSEAL, large quantities of resin sealer infiltrated into dentinal tubulars deeply and formed long, continuous and densely tags. In specimens obturated with AH Plus, the relative long, densely arranged resin tags were seemed to be discontinuous. In specimens bulkly filled with RealSeal SE, the tags were less frequent and appeared short and sparse.Conclusion:Under the condition of completely remove smear layer, MetaSEAL showed spectacular bond ability to root dentin. Compared with AH Plus, RealSeal SE's bond ability has no distinguished difference. From the viewpoint of material science, this study suggested truly potential bondability to root dentin of self-adhesive methacrylate resin-based sealer. |
PDF Full Text Request