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BACKGROUND:Studies have shown that chronic apical periodontitis is one of the common inflammatory bone destruction diseases.Icariin can promote osteogenic differentiation,inhibit bone resorption,and may play a protective role in bone destruction caused by chronic apical periodontitis. OBJECTIVE:To investigate the effect of icariin on the proliferation and differentiation of MC3T3-E1 cells in the inflammatory environment stimulated by lipopolysaccharides. METHODS:Lipopolysaccharides were used to stimulate MC3T3-E1 cells to establish an inflammatory environment in vitro,and cell counting kit-8 was used to detect the best concentration and optimal action time of lipopolysaccharides.Cell counting kit-8 was used to detect the optimal concentration of icariin under the stimulation of lipopolysaccharides at a concentration of 1 μg/mL.Alkaline phosphatase detection,Real-time PCR and western blot assay were used to detect the effect of icariin on osteogenic differentiation of MC3T3-E1 cells in the inflammatory environment.Real-time PCR and western blot were used to detect the effects of icariin on the expression of interleukin-1β and interleukin-6 in MC3T3-E1 cells in the lipopolysaccharide-stimulated inflammatory environment. RESULTS AND CONCLUSION:Cell counting kit-8 results showed that the optimal concentration of icariin was 0.1 μg/mL.In the inflammatory environment,icariin enhanced the expression of alkaline phosphatase and promoted osteoblast differentiation.Compared with the lipopolysaccharide group,the expression of osteogenesis-related factors alkaline phosphatase and Runx2 was increased in the lipopolysaccharide+icariin group.Compared with the lipopolysaccharide group,the expression levels of inflammation-related factors interleukin-1β and interleukin-6 decreased in the lipopolysaccharide+icariin group.To conclude,lipopolysaccharides weaken the osteogenic ability of MC3T3-E1 cells and aggravate the inflammatory response,but icariin has a protective effect on them.
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Objective:To investigate the influence of 3 methods of fiber posts on fracture resistance of maxillary anterior teeth with flared root canals.Methods:32 human maxillary central incisors were assigned randomly to 4 groups(n =8).The crowns of the teeth were removed at a level 2 mm incisal to the cementoenamel junction(CEJ).After root canal therapy,flared canals were simula-ted in 3 groups.The flared canals were reinforced with resin cement(group A),resin composite(group B)and accessory posts (group C)respectively.In group D flared canals were not created.The same size fiber posts were cemented with resin cement in all groups.After posts cementation and composite resin core formation,all teeth were restored with metal crowns.Then the roots of the teeth were embedded in acrylic resin blocks up to 2 mm below the CEJ.The samples were loaded in a testing machine until failure occurred.Results:The maximum load value(N)for fracture of group A,B,C and D was 295.94 ±69.11,450.51 ±54.68, 479.37 ±77.81 and 618.51 ±87.42 respectively(F =118.127,P =0.000);group B vs C,P >0.05,between each 2 of the other groups,P 0.05). Conclusion:Reinforcement of flared canal with resin composite and accessory posts can increase the fracture restance of the tooth root and the most of fracture patterns are beneficial for the second repair.
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BACKGROUND:Severely curved root canal preparation is the difficulty during clinical root canal preparation, and improper preparation may induce complications such as stage, root canal offset and apical open, which affect the quality of root canal preparation and apical closure. Therefore, it is important to choose a root canal preparation instrument which has the best cutting and forming ability. OBJECTIVE: To compare the shaping ability of Mtwo nickel-titanium rotary instruments, K3 nickel-titanium rotary instruments and stainless steel K-files for the preparation of curved root canals. METHODS:A total of 30 severely curved root canals of freshly extracted human maxilary molars were randomly divided into three groups, with 10 canals in each group. The canals were prepared by Mtwo instruments, K3 instruments and K-files, respectively. The instrument’s tip location in pre- and post-instrumentation radiographs of the three groups was recorded; the changes of root curvature, working length and working time in the three groups were measured and compared. RESULTS AND CONCLUSION:The root curvature showed no significant difference in the three groups before preparation (P> 0.05). The changes of root curvature after root preparation in Mtwo instrument and K3 instrument groups were significantly less than that in K-files group (P 0.05). The root canal preparation time in the three groups showed significant differences (P 0.05). Mtwo nickel-titanium rotary instruments and K3 nickel-titanium rotary instruments are have high efficacy and strong shaping ability in preparing curved root canals.
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<p><b>OBJECTIVE</b>To detect the ability of Enterococcus faecalis (E. faecalis) biofilm formation and explore the relationship between E. faecalis biofilm formation ability and clinical manifestation.</p><p><b>METHODS</b>96 well plate with the establishment of 53 E. faecalis in vitro biofilm model, combined with crystal violet staining, was used to test the biofilm formation ability of the clinical isolates E. faecalis and analyze the relationship between biofilm formation capacity and clinical manifestation.</p><p><b>RESULTS</b>In total 53 E. faecalis strains, 40 strains(75.47%) had biofilm forming ability. Statistical analysis revealed that the capacities of biofilm formation between E. faecalis isolated from with fistula and without fistula was significantly different (P<0.05).</p><p><b>CONCLUSION</b>In the retreatment of root canal, the ability of biofilm formation of E. faecalis separated from the teeth without fistula is better than those separated from the teeth with fistula.</p>
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Humanos , Biopelículas , Cavidad Pulpar , Enterococcus faecalis , Retratamiento , Tratamiento del Conducto RadicularRESUMEN
Objective To assess the efficacy of NaClO irrigation of root canal at different temperatures.(Methods Thirty) human teeth with single root-canal mandible premolar were instrumented using standard technique,then were divided into 3 groups,carrying on root-canal irrigation.group A: 5.25% NaClO+System B,group B:5.25% NaClO+15% EDTA,group C:5.25% NaClO+System B+15% EDTA.After the teeth root were split,the scanning electron microscope was used to observe the coronal third,middle third and apical third parts.(Results The) amount of remaining debris on root canal wall in group C decreased significantly,compared with group A and B.The differences of coronal third and middle third between group A and B,group B and C,group A and C were significant(P0.05),but there were significant differences between group A,B and C(P
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In order to adapt to the development of society,an innovative talent cultivation system has been explored to train stomatological specialists with active innovation spirit and strong ability to practise.
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Objective:To evaluate the ability of calcium hydroxide removal using different irrigation methods and the effect on canal sealing.Methods:200 human single root canal premolar teeth were prepared.Divided the teeth randomly into 2 groups(each group 96 teeth,8 as control),one group filled with chemical calcium hydroxide and another filled with finished product calcium hydroxide.7 days after,divided each groups randomly into 6 subsets and remove the calcium hydroxide in the root canal(table1).Then each subset group choose 8 teeth randomly,observed by scanning electron microscope.Other specimens were obturated by lateral condensation of cold gutta-percha with a AH-Plus sealer,stained by Indian ink and then made into transparent teeth model.Results:At the same condition,there was no significant difference between group A and group B;the results of groups associated with ultrasonic were better than groups with injection syringe.The rinse solution EDTA was the best,distilled water was the worse.Dye penetration showed that the length of dye staining was no significant difference among all groups.Conclusion:Ultrasonic and sodium hypochlorite associate EDTA is the best method to remove the calcium hydroxide.But none of the methods and rinse solution used in this experiment can remove all of the calcium hydroxide.The calcium hydroxide remained influence on the root canal sealer is not predominance.