| Objective:Effective root canal disinfection and establishment of a microenvironment conducive to the proliferation and differentiation of stem cells are the necessary prerequisites to successful pulp treatment of immature permanent teeth.Root canal disinfection should control of infection effectively while having no cytotoxicity effect on dental stem cells,restoring the potential of root continual development of immature permanent teeth.Traditionally,the most widely used intracanal medicaments are calcium hydroxide[Ca（OH）2]and triple antibiotic paste（TAP）.They have detrimental effect of dental stem cells although they can provide satisfied disinfection.iRoot FM,as a novel bioceramic material,was introduced in endodontic treatment,especially in immature permanent teeth.An advantage of i Root FM is its excellent biocompatibility and stable in chemical properties.In this study,we evaluated the antibacterial activities of iRoot FM against Porphyromonas endodontalis（P.endodontalis）ATCC35406 and investigated the proliferation and differentiation of SCAP exposed to iRoot FM.Materials and Methods:1.Bacteriological test:the agar diffusion test model was established to compare the antimicrobial efficacy of iRoot FM with two traditional intracanal medicaments,Ca（OH）2 and TAP according to the inhibition zones against P.endodontalis;The antibacterial broth test was used to detect the minimum bactericidal concentrations of i Root FM,Ca（OH）2 and TAP.2.Cytology test:first of all,we prepared series of concentrations conditioned medium of i Root FM,Ca（OH）2 and TAP,measured the pH levels of these samples,and then cultured SCAP,separately.The CCK-8 assay was used to assess the proliferation rate of SCAP when exposed to the three intracanal medicaments after 1,3,5 d.The expression levels of ALP and DMP-1were used to evaluate the osteo-/odontogenic differentiation of SCAP,as assessed by real-time PCR,Western blotting.And the capacity to form mineralized nodules was assessed by alizarin red S staining.The experimental data were analyzed statistically using SPSS 17.0 software package,and comparisons between each of two groups were analyzed by the least significance difference（LSD）method.P values less than0.05 were considered statistically significant.Results:The zone of inhibition against P.endodontalis produced by iRoot FM was20.74±4.35 mm,while the zones of inhibition of Ca（OH）2 and TAP were 24.89±3.84 mm and 34.51±1.20 mm.TAP had the strongest antibacterial capacity.iRoot FM also had a strong antibacterial capacity,and was similar to that of Ca（OH）2（P>0.05）.The MBC of iRoot FM,Ca（OH）2,and TAP were 12.5 mg/mL,2.5 mg/mL,and0.01 mg/mL,respectively.The pH value of different concentrations of iRoot FM was stable,while those of Ca（OH）2 and TAP were significantly increased or decreased with increasing concentrations.We found that low doses of iRoot FM significantly elevated the proliferation rate of SCAP,and high doses of iRoot FM had no significant effects.While high doses of Ca（OH）2markedly decreased the proliferation rate.We found that iRoot FM was significantly increased the expression levels of DMP-1 and ALP of SCAP.Ca（OH）2 had no significant effect on the expression levels of DMP-1and ALP,while TAP markedly reduced the expression levels of both DMP-1 and ALP.SCAP,cultured in conditioned medium with iRoot FM showed higher capacity of mineralization than that in Ca（OH）2 and TAP（P<0.05）.Conclusions:iRoot FM,the novel bioceramic material,exhibited strong antibacterial activity against P.endodontalis and had no cytotoxicity effect on SCAP,also could improve the proliferation and osteo-/odontogenic differentiation of SCAP in low doses.The findings provide valuable evidence that i Root FM is a promising intracanal medicament for endodontic procedures in immature permanent teeth. |
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