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Objective@#To analyze effect of fractured file removal from the middle third root canal on root fracture resistance using finite element analysis, which provides a theoretical basis for clinical prognosis evaluation.@*Methods@#Two finite-element models were established, the fractured file removal model (fractured file located in the middle third of root canals, followed by ultrasonic file removal and root canal preparation) and the control model (root canal preparation only), and compressive displacement dependencies on compressive force was computed and compared with experimental data for validation. The validated finite-element models were used to analyze the stress distribution differences during the initiation, propagation and completion of the crack between fractured file removal specimen and control one.@*Results@#The critical breaking force of the fractured file removal specimen was 406 N, and the finite element simulation result was 396 N. The critical breaking force of the control specimen was 502 N, and the finite element simulation result was 483 N. The position of crack initiation in the finite element simulation was basically consistent with that in the experiment. The experimental data of compressive test and the results of finite-element computation were in agreement, thus validating the finite-element model. In the process of continuous pressure, the stress distribution of the control root is relatively uniform, and the location of crack initiation and the direction of propagation have a certain unpredictability. Compared with the control root, the stress concentration on the root with fracture file removal was obvious, especially on edges, and the number of cracks are much more. Because of the thinner radicular wall, the crack propagation rate is faster too. Therefore, the overall root fracture resistant is decreased obviously.@*Conclusions@#During the fractured file removal procedure, amount of dentine removed should be minimized, and the edges and corners which caused by fractured file removal should be shaped to smooth in order to reduce the stress concentration and prevent the root from fracture.
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Objective@#To evaluate the use of dental operating microscope in treating calcified canals. @*Methods@#369 calcified canals were treated with C-Pilot files and ethylene diamine tetraacetic acid (EDTA) under dental operating microscope. The canals were grouped based on the calcified teeth site and calcified location in canals, and then the success rates of negotiating were analyzed with χ2 test.@*Results @#310 of 369 calcified canals were negotiated under dental operating microscope, the negotiating rate was 84.01%. For the anterior, premolar and molar, the negotiating rate were 94.78%, 85.98%, and 74.15% respectively. There were significant differences between anterior and molar teeth (χ2 = 19.658, P<0.05). When the calcification was located in straight canals or above the root canal curvature, canals were negotiated with a success rate of 96.85%. However, it decreased to 39.76% when the calcified portion located below the root canal curvature (χ2 = 156.113, P<0.05).@*Conclusion @# It is an effective way to use dental operating microscope and C-Pilot files to treat calcified canals, but the therapeutic effects might be affected by sites of the teeth and the calcified location in canals.
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Objective To study the therapeutic effect of rheum(Chinese herbal medicine) preparation made by using ultrasonic technique on pro-inflammatory cytokines and sepsis in rats.In order to offer novel measure for the treatment of critically ill patients.Methods Firstly, rheum sterile solution was prepared through ultrasonic technique.Secondly, fifty healthy male SD rats were randomly(random number) divided to CLP group and rheum group.Moderate degree of sepsis model was established by using cecal ligation and puncture(CLP).Rats in group rheum received the liquid rheumpreparation via intragastric administration, while rats in group CLP received saline instead.The 7-day survival rate was recorded and was compared between two groups.In addition, another fifty-four rats were randomly(random number) divided to sham group, CLP group and rheum group(n=18 in each group).CLP was performed to induce sepsis in CLP group and rheum group.Then rats in rheum group received rheum sterile solution via intragastric administration, while rats in CLP group received saline instead.At 12 hours, 24 hours and 48 hours after modeling, six rats in each group were randomly sacrificed.Serum TNF-α and HMGB1 levels were detected by ELISA method.Levels of RAGE, HMGB1 and NF-κB P65 in small intestine were detected by Western Blot.Results Level of anthraquinones extracted from rheum by ultrasonic technique was higher than that by conwentional decoction method.The 7-day survival rate of rats in rheum group(76%) was higher than that in CLP group(48%)(P0.05).At 24 hours and 48 hours after modeling, serum HMGB1 levels were significantly lower in rheum group than those in CLP group(P<0.05).Compared with sham group, protein levels of HMGB1, RAGE and NF-κB in small intestine were elevated in CLP group and rheum group at 48 hours after modeling(P<0.01), while protein levels of above biomarker were higher in CLP group than those in rheum group(P<0.05).Conclusions Rheum sterile solution could down-regulate the level of pro-inflammatory cytokines, modulate the inflammatory response, and improve the survival rate in rats with sepsis.
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The application of transesophageal echocardiography (TEE) in perioperative monitoring was introduced,and its involvement in non-cardiac surgery was described.The advantages and disadvantages of TEE were analyzed when applied to cardiac and non-cardiac operations for congenital heart disease,coronary disease,vascular heart disease,aorta disease and etc.The abuse of vasoactive drug or fluid is avoided due to subjective evaluation on cardiac function and volume load.TEE facilitates the anesthetist in diagnosis and evaluation of the patient with heart diseases,and the surgeon in immediate assessment of the operation,which can be used for real-time monitoring of cardiac function and hemodynamics.
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This paper summarizes 6 cases with multi-fracture of dental instruments in tooth root canal treated in our hospital from June 2011 to July 2013,the creation of a straight pathway,establishment of collateral bypass ,ultrasonic vibration,prevention of root perforation and secondary instrument fracture were emphasized,a reference in dealing with similar situations was provided.
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Objective To evaluate the effect of one-visit endodontic treatment for infected root canals with combination of nickel-titanium instruments and ultrasonic technique and warm vertical technique.Methods According to treatment,90 teeth were randomly divided into experimental and control groups.Two groups were used nickel titarlium root canal preparation.Experimental group:51 teeth for ultrasonic root canal irrigation,and warm vertical technique was employed to fill the root canal.Control group:39 teeth for rinse syringes,and warm vertical technique was employed to fill the root canal.Washing fluid was 2％ sodium hypochlorite.The root canal filling was observed after a week and one year of postoperative pain response.Results A week later,two groups of post-operative pain showed that there was significant difference in responses (x2 =15.525,P ＜ 0.05).One year later,the two groups showed no significant difference in efficacy(x2 =0.085,P ＞ 0.05).Conclusion The combination of nickel-titanium instruments and ultrasonic irrigation technique and warm vertical obturation,for the treatment of infected root canals was a method to complete the root canal filling,could reduce both the number of patients subsquent visits and the postoperative pain response,while it could improve the quality of root canal filling.
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Objective To observe the effect of the dental operative microscope(DOM) and the ultrasonic apparatus in detecting the mesiobuccal root canal orifice of the maxillary first permanent molar(MFPM). Methods According to traditional method,the pulp chamber was opened and the second mesiobuccal root canals(MB2) were explored in 76 MFPM teeth.If MB2 was not found,then we modified the shapes of the pulp chambers and detected the orifices.At last,MB2,not found under naked eyes,was explored with DOM and ultrasonic technique. Results The detection rate of the second mesiobuccal orifice of MFPM was 81.6%.The rate was only 31.6% when using traditional method,while after modifying the shapes of the pulp chambers there was an increase of 30.2% under naked eyes and then another 19.7% increase was obtained by using DOM and ultrasonic apparatus.The distance between two mesiobuccal root canal orifices was(1.42?0.51) mm. Conclusion It is helpful to find some invisible orifice of MB2 by using DOM and ultrasonic technique,and it would be beneficial to improve the root canal therapy.
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0.05).Conclusions:Metronidazole and chlorhexidine were ideal root canal ultrasonic irrigations and they could kill bacteria of root canal and prevent the incidence of postoperative pain,so it can increase success of root canal therapy.
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The principle method and application of the ultrasonic technique are briefly recommended. As compared with acute experiment, this technique has the following merits: the determination is not affected by anesthesia and damage, the animal is in physiologic state, the sensitivity of apparatus is heigher, the result is more accurate, the changes in the contractory state of the ventricular wall and the parameters of cardiac function can be recorded synchronously, and the correlation analysis can be made more accurately. This method is suitable for chronic cardiovascular function experiments of physiology, Pharmacology and pathophysiology.