ABSTRACT
Objective@#To explore effect on the remineralization of demineralized enamel surfaces with glycine-guided carboxymethyl chitosan (CMC)/amorphous calcium phosphate (ACP).@*Methods@# Remineralized solultion at different stages were prepared: ①reactive CMC/ACP (CMC/ACP nanoparticles treated with NaClO), ②reactive CMC/ACP+glycine; transmission electron microscopy was used to detect the morphology of the remineralized solution particles. Twenty teeth were randomly divided into two groups: group A and group B. Reactive CMC/ACP was applied to the enamel surface of group A and group B was treated with reactive CMC/ACP remineralization solution containing glycine. Scanning electron microscopy was used to detect the enamel surface morphology before and after remineralization, and nanoindentation was used to detect the mechanical strength (including nanoindentation depth, hardness and elastic modulus) of the enamel surface.@*Results@#Under a transmission electron microscope, the particles in the reactive CMC/ACP remineralization solution were smooth, and the increase in particle size was approximately 100-300 nm. After the addition of glycine, the particles in the reactive CMC/ACP remineralization solution particles showed a linear ordered arrangement, and microcrystals were formed in the solution 15 min later, with a crystal length of approximately 5-15 μm. Remineralization in group A was granular and heterogeneous. In group B, the crystal morphology of the demineralized enamel was homogeneous and ordered, similar to that of natural enamel. The nanoindentation depth of group B after remineralization was smaller than that of group A, and it was closest to that of natural enamel, there was no significant difference between group B and natural enamel in terms of the hardness and elastic modulus of the enamel surface after remineralization.@*Conclusion@# CMC/ACP nanoparticles treated with NaClO can rapidly and specifically form directional and ordered remineralization on the enamel surface of a model of glycine-guided rapid remineralization of enamel caries. The surface structure of remineralized enamel is similar to that of natural enamel in terms of nanoindentation depth, hardness and elastic modulus.
ABSTRACT
Objective@#To compare the efficacy of different methods in the removal of calcium hydroxide from root canals and to provide a reference for clinical treatment. @*Methods@# A total of 160 extracted single-rooted mandibular premolars were instrumented up to ProTaper Universal F4. The roots were split longitudinally, and standardized groove and depression models were prepared and filled with calcium hydroxide. The samples were randomly divided into 4 groups (n=40) according to different irrigation methods: syringe needle irrigation, passive ultrasonic irrigation, XP-endo finisher (XPF) irrigation, and M3-Max irrigation. Each group was then divided into 2 subgroups (n=20) according to the irrigation protocol: NaOCl and NaOCl+EDTA. Photos of grooves and depressions were taken under a microscope after irrigation, and the residual calcium hydroxide was scored to compare the removal effects of different irritation methods and solutions.@*Results@#In the groove and depression model, when sodium hypochlorite is used as the irrigation fluid, ultrasound irrigation, XPF and M3-Max are better than syringe needle irrigation in removing calcium hydroxide (P < 0.05); when sodium hypochlorite combined with EDTA flushing, the effect of removing calcium hydroxide with ultrasound irrigation, XPF and M3-Max is better than that of syringe needle irrigation (P < 0.05); but there is no statistically significant difference between ultrasound, XPF and M3-Max (P > 0.05); when compared with the use of sodium hypochlorite, the combined use of EDTA irrigation could enhance the effect of ultrasonic irrigation, XPF and M3 Max on the removal of calcium hydroxide (P < 0.05), but there was no significant improvement in the syringe needle irrigation group (P > 0.05). @*Conclusion @#Sodium hypochlorite combined with EDTA can enhance the effect of ultrasonic irrigation, XPF and M3 Max on the removal of calcium hydroxide, and there is no significant difference among these approaches, which are more effective than syringe needle irrigation.
ABSTRACT
90 extracted single rooted human teeth were inoculated with E.faecalis.The cannals of the teeth were irrigated with MTAD, 5.25% NaClO,compound chlorhexidine gargle,tinidazole mouthwash,distilled H2 O(infection control)and autoclave followed by distilled H2 O(autoclaving control),respectively(n =1 5).Then E.faecalis infection of the samples were examined.The results showed that MTAD had significantly greater antibacterial effects than 5.25% NaClO,tinidazole mouthwashes,compound chlorhexidine gargle and tinidazole mouthwash(P <0.05).There was no significant difference between each 2 of the other 3 irrigants.