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Objective To evaluate clinical effect of the handling ProTaper Nickel-titanium rotary instruments in preparation of canals of posterior teeth.Methods 96teeth with pulpitis or periapical periodontitis were instrumented by handling ProTaper rotary instruments using step-down technique,and by K files using step-back technique for control.All teeth were obturated with lateral condensation methods.The efficiency of preparation was analyzed with ra-diographs before and after operation.

目的 评价手用ProTaper预备后牙根管的临床效果方法选取患有牙髓炎和根尖周炎的后牙96例，随机分成试验组和对照组各48例，试验组用手用ProTaper 锥度镍钛旋转器械逐步伸入法预备根管，对照组用K锉，逐步后退法预备根管，两组均用侧向加压充填法充填根管，根据治疗后的X线片，评价后牙根管预备效果。

Methods 96teeth with pulpitis or periapical periodontitis were instrumented by handling ProTaper rotary instruments using step-down technique,and by K files using step-back technique for control.All teeth were obturated with lateral condensation methods.The efficiency of preparation was analyzed with ra-diographs before and after operation.

选取患有牙髓炎和根尖周炎的后牙96例，随机分成试验组和对照组各48例，试验组用手用ProTaper多锥度镍钛旋转器械逐步伸入法预备根管，对照组用K锉，逐步后退法预备根管，两组均用侧向加压充填法充填根管，根据治疗前后的X线片，评价后牙根管预备效果。

objective to evaluate clinical effect of the handling protaper nickel-titanium rotary instruments in preparation of canals of posterior teeth.methods 96teeth with pulpitis or periapical periodontitis were instrumented by handling protaper rotary instruments using step-down technique,and by k files using step-back technique for control.all teeth were obturated with lateral condensation methods.the efficiency of preparation was analyzed with ra-diographs before and after operation.results no transportation,apical blockage and ledge were found in test.the technique could keep canals smooth.there were two ledge,one instrument fracture and nine transportation in control.the operative time was shorter and post treatment pain seldom occurred in handling protaper group.conclusion the handling protaper niti rotary instruments can prepare the canals effectively and safety.after the preparation,the canals could be easily washed,sterilized and filled.it is an efficient instrumentation method for posterior teeth's canals and be used widely.

目的 评价手用protaper预备后牙根管的临床效果。方法选取患有牙髓炎和根尖周炎的后牙96例，随机分成试验组和对照组各48例，试验组用手用protaper多锥度镍钛旋转器械逐步伸入法预备根管，对照组用k锉，逐步后退法预备根管，两组均用侧向加压充填法充填根管，根据治疗前后的x线片，评价后牙根管预备效果。结果试验组无根管偏移、根尖阻塞、台阶，且根管壁平滑流畅，无器械折断等并发症发生。对照组有2例台阶形成，器械折断1例，根管偏移9例。试验组操作时间短且术后疼痛轻微。结论应用手用protaper预备后牙根管快速、安全，成形效果好，易于根管冲洗消毒及填充，可视为临床上预备后牙根管的有效方法。

With Death guitarist Schuldiner adopting vocal duties, the band made a major impact on the scene.

随着死亡的吉他手Schuldiner接受主唱的职务，乐队在现实中树立了重要的影响。

But he could still end up breakfasting on Swiss-government issue muesli because all six are accused of nicking around 45 million pounds they should have paid to FIFA.

不过他最后仍有可能沦为瑞士政府&议事餐桌&上的一道早餐，因为这所有六个人都被指控把本应支付给国际足联的大约4500万英镑骗了个精光。