Hesperidin attenuates arsenic trioxide-induced cardiac toxicity in rats

Objective:To explore the cardioprotective effect of hesperidin against arsenic trioxide-induced cardiac toxicity in rats.Methods:Cardiac toxicity was induced by oral administration of 4 mg/kg arsenic trioxide for 30 days.Hematological,biochemical,electrocardiography,echocardiography,and histopathological examinations were performed.Results:Hesperidin decreased the neutrophil-to-lymphocyte ratio,calcium,creatine kinase-myoglobin binding,lactate dehydrogenase,IL-6,and lipid peroxidation,as well as increased sodium and potassium concentration and superoxide dismutase and catalase activity in arsenic trioxide-intoxicated rats.Moreover,it reduced peak systolic velocity and end-diastolic velocity while increasing heart rate.Arsenic trioxide-induced histopathological damage to cardiac tissue was prominently alleviated by hesperidin treatment.Conclusions:Hesperidin attenuates arsenic trioxide-induced cardiac toxicity in rats.Therefore,it can be further explored as a cardioprotective agent.

Plasma synthesis of various polymorphs of tungsten trioxide nanoparticles using gliding electric discharge in humid air:characterization and photocatalytic properties

A gliding electric arc(glidarc)discharge generates a low-temperature plasma at atmospheric pressure.When the discharge occurs in humid air as the feed gas,the chemistry of a glidarc plasma consists of in situ formation of HO°and NO°as the primary chemical species.Tungsten trioxide(WO_(3))nanoparticles were successfully prepared by exposure of a liquid precursor to glidarc plasma.The WO_(3)samples were calcined at three different temperatures(300℃,500℃and 800℃),resulting in different pure polymorphs:γ-WO_(3)(at 300℃),β-WO_(3)(at 500℃)andα-WO_(3)(at 800℃)according to x-ray diffraction analysis.The identification of WO_(3)compounds was also confirmed by attenuated total reflection Fourier transform infrared spectroscopy analysis.Increase in the calcination temperature of WO_(3)induced a decrease in its specific surface area according to Brunauer–Emmett–Teller nitrogen physisorption analysis.The UV-visible results showed that the absorption bands of plasma-WO_(3)samples were more intense than those of WO_(3)samples obtained by a precipitation route,a classical method used for comparison.Consequently,this parameter can improve the photocatalytic properties of WO_(3)under visible light.The photodegradation(in sunlight conditions)of gentian violet,chosen as a model pollutant,confirmed the photocatalytic properties of plasma-WO_(3)samples.This novel synthesis method has great potential to improve the efficiency of advanced tungsten trioxide-based functional material preparation,as well as in pollution-reducing and energy-saving tungsten extractive metallurgy.

Giant saturation absorption of tungsten trioxide film prepared based on the seedless layer hydrothermal method

Nonlinear materials have gained wide interest as saturable absorbers and pulse compression for pulsed laser applications due to their unique optical properties.This work investigates the third-order nonlinear phenomenon of tungsten trioxide(WO_(3))thin films.The giant nonlinear absorption and nonlinear refractive index of WO_(3)thin films were characterized by Z-scan method at 800 nm.We experimentally observed the giant saturable absorption(SA)and nonlinear refractive index of WO_(3)thin films prepared by the seedless layer hydrothermal method,with SA coefficient being as high as-2.59×105cm·GW^(-1).The SA coefficient is at least one order of magnitude larger than those of the conventional semiconductors.The nonlinear refractive index n_(2)of WO_(3)film has been observed for the first time in recent studies and the corresponding coefficient can be up to 1.793 cm^(2)·GW^(-1).The large third-order nonlinear optical(NLO)response enables WO_(3)thin films to be promising candidates for optoelectronic and photonic applications in the near-infrared domain.

Induction of apoptosis by arsenic trioxide and hydroxycamptothecin in gastric cancer cells in vitro

AIM To study the effects of arsenic trioxide andHCPT on different degrees of differentiated gastriccancer cells（SGC-7901,MKN-45,MKN-28）withrespect to both cytotoxicity and induction ofapoptosis in vitro.METHODS The cytotoxicity of As2O3 and HCPTon gastric cancer cells was determined by MTTassay.Morphologic changes of apoptosis ofgastric cancer cells were observed by lightmicroscopy and transmission electron microscopy.Apoptosis and cell cycle changes of gastric cancercells induced by HCPT and As2O3 were investigatedby TUNEL method and flow cytometry.RESULTS As2O3 and HCPT had remarkablecytotoxic effects on different degrees ofdifferentiated gastric cancer cells.The IC50ofAs2O3 on well differentiated gastric cancer cellMKN-28,moderately differentiated gastric cancercell SGC-7901,and poorly differentiated gastriccancer cell MKN-28 were 8.91 μmol/L,10.57μmol/L,and 11.65 μmol/L,respectively.The IC50of HCPT on MKN-28,SGC-7901,and MKN-45 were9.35 mg/L,10.21 mg/L,and 12.63 mg/Lrespectively after 48 h treatment.After 12 h ofexposure to both drugs,gastric cancer cellsexhibited morphologic features of apoptosis,including cell shrinkage,nuclear condensation, and formation of apoptotic bodies.A typicalsubdiploid peak before G0/G1 phase was observedby flow cytometry.The apoptotic rates of SGC-7901,MKN-45,and MKN-28 were 13.84%,22.52%,and 9.68%,respectively after 48 hexposure to 10 μmol/L As2O3.The apoptotic ratesof SGC-7901,MKN-45,and MKN-28 were 21.88%,12.35%,and 30.26%,respectively after 48 hexposure to 10 mg/L HCPT.The apoptotic indicewere 7%-15% as assessed by TUNEL method.The effect of As2O3 on SGC-7901 showedremarkable cell cycle specificity,which inducedcell death in G1 phase,and blocked G2/M phase.HCPT also showed a remarkable cell cyclespecificity,by inducing cell death and apoptosis inG1 phase and arrest of proliferation at S phase.CONCLUSION As2O3 and HCPT exhibitsignificant cytotoxicity on gastric cancer cells byinduction of apoptosis.As2O3 and HCPT mighthave a promising prospect in the treatment ofgastric cancer,which needs to be further studied.

A study on arsenic trioxide inducing in vitro apoptosis of gastric cancer cell lines

INTRODUCTION Cell apoptosis,which involves the biologic regulation of the numbers and vital activity of cells,is an important metaboloc process in both normal cells and tumor cells.

Effect of arsenic trioxide on human hepatoma cell line BEL-7402 cultured in vitro

AIM To study the effect of a varyingconcentrations of arsenic trioxide on humanhepatoma cell line BEL-?402 cultured in vitro andits mechanism of action.METHODS The BEL-7402 cells were treatedwith arsenic trioxide（at the concentrations of0.5,1,2 μmol/L,respectively）for 4 successivedays.The cell growth and proliferation wereobserved by cell counting and cell-growth curve.Morphologic changes were studied withelectronmicroscopy.Flow cytometry was usedto assay celI-DNA distribution and the proteinexpression of Bcl-2 and Bax detected byimmunocytochemical method.RESULTS The cell growth was significantlyinhibited by varying concentrations of arsenictrioxide as revealed by cell counting and cell-growth curve,which was dose- and time-dependent.Arsenic trioxide treatment at 0.5,1and 2 μmol/L resulted in a sub-G1 cell peak,theapoptosis rate of the control group was 9.31%and that of 0.5 μmol/L arsenic trioxide 15.53%,no significant difference was seen between thetwo.The apoptosis rates of 1,2 μmol/L arsenictrioxide were 19.10% and 21.87% respectively,which were much higher（both P【0.05）.Decrease of G0/G1 phase cells and increase of Sphase cells were observed by flow cytometry,suggesting the inhibition effect of 0.5,1,2 μmol/L arsenic trioxide on BEL-7402 cell lay in the G0/G1 phase.Morphologic changes such asintact cell membrane,nucleic condensation,apoptotic body formation were seen undertransmission electronmicrescopy,whereas the0.5 mol/L arsenic trioxide-treated BEL-7402cells showed decrease of nucleocytoplasmicratio,round nucleus,well-differentiatedorganelles in the cytoplasm.The processes andmicrovilli on the cell surface of the experimentalgroups under scanning electron microscopy weresignificantly decreased.High expressions ofBcl-2 and Bax were detected in 1 and 2 μmol/Larsenic trioxide-treated cells,these were 46%,87.33% and 83.08%,95.83% respectively,among which that of Bax was more significant.Arsenic trioxide treatment at 0.5 μmol/Lresulted in a higher expression level of Bcl-2 andlower expression level of Bax,which were8.81% and 3.83% respectively,as comparedwith that of the control group（15.33%）（P1【0.01,P2【0.01）.CONCLUSION Arsenic trioxide not onlyinhibited proliferation but also induced apoptosisof human hepatoma cell line BEL-7402.Theinduced-apoptosis effect of 1,2 μmol/L arsenictrioxide was related to the expression level ofBcl-2 and Bax.

Recent advances in arsenic trioxide encapsulated nanoparticles as drug delivery agents to solid cancers

Since arsenic trioxide was first approved as the front line therapy for acute promyelocytic leukemia 25 years ago,its anti-cancer properties for various malignancies have been under intense investigation.However,the clinical successes of arsenic trioxide in treating hematological cancers have not been translated to solid cancers.This is due to arsenic＇s rapid clearance by the body＇s immune system before reaching the tumor site.Several attempts have henceforth been made to increase its bioavailability toward solid cancers without increasing its dosage albeit without much success.This review summarizes the past and current utilization of arsenic trioxide in the medical field with primary focus on the implementation of nanotechnology for arsenic trioxide delivery to solid cancer cells.Different approaches that have been employed to increase arsenic＇s efficacy,specificity and bioavailability to solid cancer cells were evaluated and compared.The potential of combining different approaches or tailoring delivery vehicles to target specific types of solid cancers according to individual cancer characteristics and arsenic chemistry is proposed and discussed.

Arsenic trioxide induces apoptosis of human gastrointestinal cancer cells

AIM:To investigate the changes in apoptosis in gastrointestinal cancer cells from patients with gastrointestinal cancers treated with arsenic trioxide(As2O3);and to study the possible molecular mechanisms of such changes by detecting the expression levels of p53and Bcl-2.METHODS:Twenty patients with gastrointestinal adenocarcinoma based on endoscopic and biopsy findings(ten patients with gastric cancer and ten patients with colorectal cancer)who received treatment in our hospital between August 2007 and December 2008were included in this study.None of the patients had received anti-tumour agents prior to As2O3 treatment.As2O3 was administered intravenously at a dose of 0.01g/d diluted with 5%glucose in normal saline for 2-3h for 3 consecutive days before surgery.Morphological changes associated with apoptosis of gastrointestinal cancer cells were observed by light microscopy.Changes in the apoptotic index induced by As2O3 were investigated using the terminal deoxynucleotidyl transferase dUTP nick end labelling method.Expression levels of p53 and Bcl-2 proteins in gastrointestinal cancer tissues were determined by immunohistochemistry.RESULTS:The apoptotic index of human gastrointestinal cancer cells was higher in cells from patients treated with As2O3 than in those not treated(P<0.05).p53 protein expression in gastrointestinal tissues was unchanged by As2O3(P>0.05).However,Bcl-2 protein expression in gastrointestinal tissues was downregulated by As2O3(P<0.01).CONCLUSION:These results demonstrate that As2O3treatment in patients with gastrointestinal cancers can induce apoptosis in gastrointestinal cancer cells and down-regulate Bcl-2 protein expression.

Long-term observation of the mineral trioxide aggregate extrusion into the periapical lesion:a case series

One-step apexification using mineral trioxide aggregate(MTA) has been reported as an alternative treatment modality with more benefits than the use of long-term calcium hydroxide for teeth with open apex.However,orthograde placement of MTA is a challenging procedure in terms of length control.This case series describes the sequence of events following apical extrusion of MTA into the periapical area during a one-step apexification procedure for maxillary central incisor with an infected immature apex.Detailed long-term observation revealed complete resolution of the periapical radiolucent lesion around the extruded MTA.These cases revealed that direct contact with MTA had no negative effects on healing of the periapical tissues.However,intentional MTA overfilling into the periapical lesion is not to be recommended.

Effect of diboron trioxide on the crushing strength and smelting mechanism of high-chromium vanadium–titanium magnetite pellets

The effect of diboron trioxide(B_2O_3) on the crushing strength and smelting mechanism of high-chromium vanadium–titanium magnetite pellets was investigated in this work. The main characterization methods were X-ray fluorescence, inductively coupled plasma–atomic emission spectroscopy, mercury injection porosimetry, X-ray diffraction, metallographic microscopy, and scanning electron microscopy–energy-dispersive X-ray spectroscopy. The results showed that the crushing strength increased greatly with increasing B_2O_3 content and that the increase in crushing strength was strongly correlated with a decrease in porosity, the formation of liquid phases, and the growth and recrystallization consolidation of hematite crystalline grains. The smelting properties were measured under simulated blast furnace conditions; the results showed that the smelting properties within a certain B_2O_3 content range were improved and optimized except in the softening stage. The valuable element B was easily transformed to the slag, and this phenomenon became increasingly evident with increasing B_2O_3 content. The formation of Ti(C,N) was mostly avoided, and the slag and melted iron were separated well during smelting with the addition of B_2O_3. The size increase of the melted iron was consistent with the gradual optimization of the dripping characteristics with increasing B_2O_3 content.

Arsenic trioxide encapsulated liposomes prepared via copper acetate gradient loading method and its antitumor efficiency

In this study, arsenic trioxide(ATO) was encapsulated in liposomes via copper acetate(Cu(OAc)2) gradients and high entrapment efficiency of over 80% was obtained. The average particle size and the zeta-potential of the liposomes were detected to be 115.1 ± 29.1 nm and-21.97 ± 0.6 m V, respectively. The TEM images showed rod-like precipitates in the inner aqueous phase, which was supposed be due to the formation of insoluble ATO–Cu complex.The in vitro drug release of ATO–Cu liposomes exhibited a sustained release over 72 h, and the release rates decreased with the increase of the p H of release media. Pharmacokinetic and tissue distribution studies of ATO liposomes showed significantly reduced plasma clearance rate, increased AUC0–12h and T1/2, and improved tumor distribution of As compared to iv administration of ATO solution. The anti-tumor effect of ATO loaded liposomes to S180 tumor-bearing mice was significantly improved with a tumor inhibition rate of 61.2%,meanwhile the toxicity of encapsulated ATO was greatly decreased. In conclusion, ATO can be effectively encapsulated into liposomes by remote loading method via Cu(OAc)2 gradients;the co-administration of ATO and Cu(Ⅱ) via liposomal formulation may find wide applications in the treatment of various tumors.

A Simple Method of Electrospun Tungsten Trioxide Nanofibers with Enhanced Visible-Light Photocatalytic Activity

The present study involves the fabrication of tungsten trioxide(WO3) nanofibers by an electrospinning technique using polyvinyl pyrrolidone(PVP)/citric acid/tungstic acid as precursor solution. It was found that the PVP concentration was one of the most crucial processing parameters determining the final properties of WO3 nanofibers. The optimum concentration of PVP was from 75 to 94 g L-1. The average diameter of the nanofibers increases with increasing the PVP concentration, whereas it is decreased after sintering and orthorhombic structure were formed at 500 °C. The photocatalytic properties of the as-synthesized nanofibers were also investigated by degrading methylene blue and twofold efficiency was obtained compared with that of commercial WO3 microparticles.

Arsenic Trioxide Inhibits Proliferation in K562 Cells by Changing Cell Cycle and Survivin Expression

To study the mechanisms involved in the inhibition of chronic myeloid leukemic cells (K562) proliferation induced by arsenic trioxide (As 2O 3) and to explore the potential role of Survivin, an inhibitor of apoptosis protein, in the regulation of As 2O 3 induced cell apoptosis, K562 cells were cultured with As 2O 3 of different concentrations. Cells were collected for proliferation analysis by MTT assay. Cell cycle distribution and cell apoptosis were analyzed by flow cytometry. Expression of Survivin protein and mRNA were detected by flow cytometry and RT-PCR, respectively. Our results showed that As 2O 3 (2-10 μmol/L) inhibited K562 cells growth effectively, but it did not induce cells apoptosis significantly. The percentage of K562 cells at G 2/M phase increased in proportion to As 2O 3 concentrations, and the expression of Survivin mRNA and content of Survivin protein was up-regulated accordingly. It is concluded that As 2O 3 inhibited K562 cells growth by inducing cell cycle arrest mainly at G 2/M phase. Over-expression of Survivin gene and protein might be one of the possible mechanisms contributing to K562 cells' resistance to As 2O 3-induced apoptosis.

Metallic vanadium trioxide intercalated with phase transformation for advanced aqueous zinc-ion batteries

Aqueous zinc-ion batteries have broad application prospects due to the eco-friendliness,cost-economy and high safety.However,the scarcity of high-performance cathodes with outstanding rate capability and long lifespan has affected their development.Herein,we report a metallic vanadium trioxide material intercalated with phase transformation as cathode applied in aqueous zinc-ion batteries.It offers satisfactory electrochemical performances with a high specific capacity(435 mAh g^(-1) at 0.5 A g^(-1)),decent power density(5.23 kW kg^(-1))and desired energy density(331 Wh kg^(-1)),as well as good cyclability.The superior performance originates from the stable structure and fast Zn^(2+)diffusion,enabled by the pre-intercalation of Zn^(2+)and water molecules.

Effect of acid etching on marginal adaptation of mineral trioxide aggregate to apical dentin:microcomputed tomography and scanning electron microscopy analysis

The present investigation assessed the effect of acid etching on marginal adaptation of white- and gray-colored mineral trioxide aggregate （MTA） to apical dentin using microcomputed tomography （micro-CT） and scanning electron microscopy （SEM）. Sixty-four extracted single-rooted human maxillary teeth were used. Following root-end resection and apical preparation, the teeth were equally divided into four groups according to the following root end filling materials： （i） white-colored MTA （WMTA）, （ii） etched WMTA （EWMTA）, （iii） gray-colored MTA （GMTA） and （iv） etched GMTA （EGMTA）. After 48 h, the interface between root-end filling materials and the dentinal walls was assessed using micro-CT and SEM. Data were statistically analyzed using the KruskaI-Wallis and Dunn tests. Micro-CT analysis revealed gap volumes between the apical cavity dentin walls and EGMTA, GMTA, EWMTA and WMTA of （0.007 1±0.004） mm3, （0.053±0.002） mm3, （0.003 6±0.001） mm3 and （0.005 9±0.002） mm3 respectively. SEM analysis revealed gap sizes for EGMTA, WMTA, EWMTA and GMTA to be （492.3±13.8） μm, （594.5±17.12）μm, （543.1±15.33） μm and （910.7±26.2）μm respectively. A significant difference in gap size between root end preparations filled with GMTA and EGMTA was found （P〈O.05）. No significance difference in gap size between WMTA and EWMTA were found in either SEM or micro-CT analysis. In conclusion, pre-etching of apical dentin can provide a better seal for GMTA but not for WMTA.

Role of Low Dosage Arsenic Trioxide on Pulmonary Dendritic Cells in Asthmatic Mice

Objective: To investigate the distribution and recruitment of pulm onary dendritic cells (DCs) and the influence of low dosage arsenic trioxide (As 2O 3) on them in the airway of asthmatic mice. Methods: Thirty BALB/c mice were randomly divided into 3 groups: the control group, the asthmat ic group and the As 2O 3 treated group. The mice asthmatic model was induced v ia sensitizing with peritoneal injection of ovalbumin (OVA) for two times and th en provocated with aerosol inhalation of OVA for a week. The treated group was p eritoneally injected with 0.2 ml solution of As 2O 3 (4mg/kg) 0.5h after each provocation. The immunohistochemistry and computerised image analysis were appli ed to detect quantitatively the DCs in the lung and airway of mice. Resul ts: All intraepithelial nonlymphoid dendritic cells 145 (NLDC 145) throughout the respiratory tree in the mice of the control group formed a netwo rk with the density of DCs varying from (575±54) cells/mm 2 epithelial surface in the large airway, to (68±12) cells/mm 2 epithelial surface in the small ai rway. The distribution of airway NLDC 145 + in the asthmatic group was simil ar to that in the control group, but its density was significantly upregulated ( P <0.01). The distribution of airway NLDC 145 in the treated group was sim ilar to that in the asthmatic group, only its density was significantly downregu lated ( P <0.01). Conclusion: There is an integral network of N LDC 145 + throughout the respiratory tree. To downregulate the density but n ot change the distribution of pulmonary DCs could be an important therapeutic me chanism of low dosage As 2O 3 in treating asthma.

Mechanism of apoptosis of human osteosarcoma M-G63 induced by arsenic trioxide

Objective To observe the apoptosis of osteosarcoma MG-63 cells induced by As2O3 and to explore its possible mechanisms. Methods The flowcytometric analysis and transmission electronmicroscope were performed to investigate the inducing apoptosis and inhibitative of As2O3 on osteosarcoma MG-63 cells. In order to study mechanism of apoptosis in MG-63 cells treated with As2 O3, microarray was performed. The down-regulated gene was confirmed by RT-PCR, Northern-blotting. Results After treated with As2O3, hypodiploid peak before G0/G1 phase was observed in MG-63 cells through FCM analysis. Loss of microvilli, condensation and fragmentation of nuclear chromatin, condensation of cytoplasmic organelles, dilatation of the endoplasmic reticulum shrinkage of cells and alterations in cell membranes and apoptosis bodies which were observed in MG-63 cells treated with As2O3 by transmission electronmicroscope. The results of microarray show that As2 O3 induced MG-63 cell apoptosis involves down-regulation of IEX-1 and the down-regulated gene is confirmed by RT-PCR and Northern-blotting.Conclusion The results show that As2 O3 selectively inhibits growth of the solid tumor MG-63 cells by triggering apoptosis and indicates MG-63 induced by As2O3 cell apoptosis may through the IEX-1 pathway.

ARSENIC TRIOXIDE DOWNREGULATES TELOMERASE ACTIVITY IN HL-60 CELLS

Objective: To evaluate whether arsenic trioxide (AS2O3) could downregulate human telomerase reverse transcriptase (hTERT) gene expression and telomerase activity during induction of apoptosis of HL-60 cells. Methods: Apoptosis was detected by morphological observation and flow cytomertric cell cycle analysis. The expression of hTERT at mRNA and protein levels was analyzed by reverse transcriptase polymerase chain reaction (RT-PCR) and immunofluorescence using fluoresce isothiocyanate (FITC) label, respectively. Telomerase activity was determined by polymerase chain reaction enzyme-linked immunoassay (PCR-ELISA). Results: Treatment of 2 μmol/L at As2O3 could induce apoptosis of HL-60 cells. hTERT was decreased at both mRNA and protein levels during apoptosis of HL-60 cells. Telomerase activity of HL-60 cells was significantly inhibited. Conclusion: It is suggested that telomerase activity of HL-60 cells might be specifically inhibited by AS2O3 through the downregulation of hTERT gene expression.

Preliminary Study of the in vitro Growth Inhibition of Human Bladder Cancer Cell Line BIU-87 by Arsenic Trioxide

To study the effects of arsenic trioxide (As2O3) on the in vitro growth of human bladder cancer cells and the mechanisms. The growth inhibition rates of human bladder cancer cell line BIU87 by various concentrations of As2O3 were detected by using MTT method. Cell apoptosis was detected by in situ terminally labeled transferase technique and bcl-2 gene expression of BIU-87 cells was observed by SABC immunohistochemical method. The results showed that As2O3 could inhibit the growth of BIU-87 effectively in a dose-dependent manner. After drug's action, the apoptotic bladder cancer cells were obviously increased, which depended on the prolongation of the action time and Bcl-2 expression of BIU-87 cells was decreased significantly. It was suggested that As2O3 could significantly inhibit the growth of bladder human cancer cells. Inducing cell apoptosis by down- regulating the expression of hcl-2 gene might be one of its action mechanisms.

Microscopic removal of type Ⅲ dens invaginatus and preparation of apical barrier with mineral trioxide aggregate in a maxillary lateral incisor:A case report and review of literature

BACKGROUND Invaginated teeth pose greater challenges in clinical management because of their complex configuration.With advancements in equipment and materials,such as the dental operation microscope,cone-beam computed tomography and mineral trioxide aggregate,the preservation rate of type Ⅲ dens invaginatus could be greatly increased.CASE SUMMARY This case report presented a 31-year-old woman with complaints of spontaneous swelling and pain in the right maxillary lateral tooth.With the aid of cone-beam computed tomography,type Ⅲ dens invaginatus with apical periodontitis was diagnosed and confirmed.Three-visit endodontic treatment was performed.In the first visit,the invagination was carefully removed under the dental operation microscope,and chemomechanical preparation was done.In the second visit,mineral trioxide aggregate apical barrier surgery was performed in this tooth.In the third visit,the canal was finally obturated with thermoplastic gutta-percha to recover the crown morphology.A 26-mo follow-up revealed a satisfied outcome both in the radiographic and oral examinations.CONCLUSION In this case,removal of the entire abnormal structure provided great convenience for the follow-up treatment.When confronted with the same clinical case in the future,we can take a similar approach to address it.