3种器械预备弯曲根管的比较研究

目的 :比较不锈钢K型锉、镍钛合金K型锉以及镍钛合金X型锉预备弯曲根管的根尖偏移。方法 :将 4 5个 15°～ 35°的弯曲前磨牙根管按弯曲度排序后均匀分成 15个区组 ,每区组 3个根管 ,再随机分配至3个不同器械处理组。根管冠部用GG钻预处理后 ,行常规法预备根管 ,拍摄数字化X线片记录预备至不同锉号时根管器械尖端所在位置。最后 ,将根管预备前后器械尖端相应位置描记后 ,在立体显微镜下测量不同锉号根管预备后的根尖偏移。结果 :3组标本的根尖偏移均随锉号的增大而增大 ,# 35和 # 4 0不锈钢K型锉根管预备所致的根尖偏移与另外两组标本相比有显著性差异 (P <0 .0 5 ) ,另有两个标本根管侧穿 ;两组镍钛合金锉之间的根尖偏移无显著性差异 (P >0 .0 5 )。结论 :对于弯曲根管 ,用镍钛合金锉预备 ,其效果优于不锈钢锉。     

三种器械预备磨牙弯曲根管成形能力的比较

目的　研究手用ProTaper与不锈钢K锉、镍钛合金K锉预备磨牙弯曲根管对根管弯曲度和根尖偏移的影 响。方法　45个弯曲度为20°~40°的磨牙根管,按弯曲度大小排序后分成15个区组,每区组3个根管,再随机分配 至3个不同处理组,每组15个根管。A组采用手用ProTaper系统行冠根向深入法根管预备;B、C组分别采用不锈钢 K锉和镍钛合金K锉行改良逐步后退法预备根管。记录3组根管预备前后根管影像及器械尖端所在位置,测量并 比较3组间根管弯曲度的变化、根尖偏移指数(ATI)和操作时间。结果　A组的根管弯曲度在根管预备前后仅改变 0·28°,明显低于B、C组,ATI亦小于B、C组(P<0·05);B组根管弯曲度的变化和ATI均大于A、C组(P<0·05);A组 的操作时间最短。结论　与不锈钢K锉、镍钛合金K锉比较,采用手用ProTaper预备磨牙弯曲根管成形效果较好, 效率较高。     

三种根管器械预备弯曲根管的效果比较

目的:比较不锈钢K型锉(K-file)、手动镍钛合金锉(N i-Ti flex)和机动镍钛锉Profile(PF)预备弯曲根管时,保持原根管解剖走向的能力。方法:选择45个离体下颌单根管前磨牙,弯曲度为20°~45°,随机分为3组,分别用不锈钢K锉(SS-K锉)、手动镍钛器械(N i-Ti flex)、机动镍钛器械Profile进行根管预备。治疗前后分别拍摄可高度重叠的X线片,通过计算机扫描和放大,分析比较各组之间维持原根管形态的差异,并记录各组的操作时间和器械分离的发生率。结果:镍钛手动器械和机动器械都能较好地保持原根管解剖走向,SS器械所致的根管偏移的数目随器械号数的增大而增加,#30以上的器械,镍钛组(包括手动和机动)保持根管解剖走向能力与SS组相比有显著差异性(P<0.05),两镍钛锉之间无显著性差异。机动镍钛组有一器械分离,操作时间机动组比手动组快(P<0.01)。结论:对于弯曲根管,当根尖部预备大于#30时,镍钛锉保持根管原解剖走向的能力优于不锈钢锉,机动器械比手动器械操作时间短。     

弯曲根管用镍钛器械预备后根管偏移的研究

目的:研究3种镍钛根管预备器械预备后牙弯曲根管产生根管偏移的情况。方法:选择48个弯曲度>25°的下颌第一、二磨牙近中根包埋于Branmante模型中,分别用机动Hero642、Profile和手用ProTaper、不锈钢K锉进行根管预备。拍摄根管预备前后根尖、根中段横截面的影像,测定根管偏移的量、方向和轴中心率。结果:Hero642和Profile在根尖段和根中段根管的偏移显著小于不锈钢K锉,手用ProTaper仅在根尖段小于不锈钢K锉; 3种镍钛器械的轴中心率均低于不锈钢K锉,而镍钛器械组间无显著性差异;镍钛器械和不锈钢器械在根尖段根管中心偏向近中侧,而在根中段不锈钢K锉和手用ProTaper根管中心多数偏向远中侧,与Hero642和Profile有显著性差异。结论:Hero642、Profile和ProTaper在预备弯曲根管时有较小的偏移及良好的中心定位作用,尤其是Hero642和Profile对根尖和根中段成形能力较佳。     

ProFile ProTaper镍钛根管器械与不锈钢K锉预备弯曲根管的比较研究

目的：比较ProFile镍钛机用根管器械，ProTaper镍钛手用根管器械和不锈钢K锉用于弯曲根管预备时的根管拉直和根尖偏移，为ProFile和ProTaper的临床应用提供实验依据。方法：将正畸前减数拔除的30个下颌第一前磨牙随机分为3组，分别用不锈钢K锉、ProTaper镍钛手用根管器械、ProFile镍钛机用根管器械做根管预备，分析评价其根管拉直和根尖偏移情况。结果：不锈钢K锉组的根管拉直、根尖偏移显著大于ProTaper和ProFile预备组。结论：ProFile和ProTaper镍钛根管预备器械与传统的不锈钢器械相比更适合弯曲根管的根管预备。     

不同根管器械预备弯曲根管的实验研究

目的比较手用不锈钢K锉、手用ProTaper锉、机用ProTaper锉在预备中、重度弯曲根管时的成形能力及其对根尖孔形态特征的影响。方法将40个树脂根管模型分为A、B、C、D组，A、B、C组各12个树脂根管模型，其中每组20°根管和30°根管各6个；D组4个树脂根管模型，均为小于5°根管。分别以手用不锈钢K锉、手用ProTaper锉、机用ProTaper锉预备根管，数码相机摄片，运用专业图像分析软件Auto-CAD比较根管偏移及根尖孔形态。结果B组中轴偏移明显高于A组和C组（P<0.05），其中C组与A组在个别根管段有显著差异（P<0.05）。预备后根尖孔B组各项值均显著高于其他各组，B3组根管值显著高于B2组（P<0.05）。相同根管弯曲度下C组值高于A组；不同弯曲度下30°根管值高于20°根管值，但均无显著性差异（P>0.05）。结论两种镍钛器械均产生根管偏移，根管弯曲度是偏移产生的主要原因；与不锈钢器械相比，镍钛器械能较好地保持原根管走向及根尖孔形态。     

ProTaper与不锈钢K锉预备弯曲根管的对比研究

目的：对比ProTaper镍钛手用根管器械和不锈钢K锉进行弯曲根管预备时的根尖偏移和根充后密度。方法：将正畸减数拔除的下颌第一前磨牙20个随机分为2组,每组10个。分别用不锈钢K锉、ProTaper镍钛手用根管器械做根管预备,对比分析并评价根尖偏移和根充后密度情况。结果：两组根管偏移发生率和根充密度存在显著性差异。结论：ProTaper镍钛根管预备器械与不锈钢器械相比更适合弯曲根管的预备。     

三种不同器械预备弯曲根管时根管偏移的实验研究

目的 :研究镍钛合金 (Nickel-titanium ,NiTi)根管预备器械与不锈钢 (stainlesssteel,SS)器械预备弯曲根管时保持原根管解剖走向的能力。方法 :选择离体的人下颌单根管前磨牙 45个 ,弯曲度为 2 0°～40°。随机分为 3组 ,分别用SS -K锉、手用NiTi器械NiTiflex、机用NiTi器械ProFile .0 4进行根管预备 ,对根管偏移结果进行对比分析。结果 :NiTi器械无 1例出现根管偏移 ,而SS器械自 # 2 5开始均可发生根管偏移 ,且随器械号的增大而增加。结论 :NiTi器械保持原根管解剖走向的能力优于SS器械 ,SS器械使偏移根管的数目随号数的增大而增加     

3种根管扩大器械预备弯曲根管的体外实验

目的：运用手持根管扩大器械预备弯曲根管，观察根尖偏移发生率，方法：选取57颗弯曲单根管离体前磨牙作为研究对象，随机分成三组，A组19颗用Lightspeed镍钛合金器械预备根管，B组运用K锉，C组运用H锉，C组运用H锉，预备方法均为逐步后退技术，使用双曝光技术判断根尖偏移情况，结论：A组中有19％的根管发生了根尖偏移，B组中有82％发生了根尖偏,C且中有88％发生了根尖偏移，结论：运用Lightspeed镍钛器械预备弯根管可以减少根尖偏移的发生。     

镍钛与不锈钢器械预备根管的比较研究

目的:观察比较手用不锈钢锉和镍钛合金机用锉预备根管的临床效果。方法:选择牙髓炎需进行去髓术的病人384例,随机分成手用不锈钢锉预备根管组(不锈钢组)、镍钛合金机用锉预备根管组(镍钛组)各192例,比较观察2组器械预备根管的临床效果。结果:①镍钛组预备后根尖偏移、根尖孔敞开等不良结果比不锈钢组显著减少(P<0.001)。②镍钛组平均弯曲度为28.8°±8.5°,显著高于不锈钢组平均弯曲度21.5°±5.5°(P<0.001)。③镍钛组预备根管的时间平均为(20.5±2.5)min,显著少于不锈钢组(30.5±5.5)min(P<0.001)。结论:应用镍钛合金机用锉预备根管,成形效果好,并发症少,操作时间短,具有良好的临床应用前景。     

Canal preparation with Hero 642 rotary Ni-Ti instruments compared with stainless steel hand K-file assessed using computed tomography

AIM: To compare ex vivo root canal preparation with conventional stainless steel K-files and Hero 642 rotary Ni-Ti instruments. METHODOLOGY: Mesiobuccal canals of 20 maxillary first molars (with angles of curvature between 25 degrees and 35 degrees ) were used. After preparation with Hero 642 rotary instruments and stainless steel K-files, the amount of transportation that occurred was assessed using computed tomography. The teeth were scanned by computed tomography before instrumentation. One millimetre thick slices were prepared from the apical end point to the pulp chamber. The first two sections were 3 mm from the apical end of the root (apical level) and 3 mm below the orifice (coronal level). A further section (mid-root level) was recorded, dividing the distance between the sections of apical and coronal levels into two equal lengths. Ten teeth were instrumented using Hero 642 rotary instruments and another 10 teeth were instrumented using stainless steel K-files. Following the completion of the instrumentation, the teeth were again scanned and compared with the cross-sectional images taken prior to canal preparation. Amount of transportation and centreing ability was assessed. Student's t-test was used for statistical analysis. RESULTS: Less transportation occurred with Hero 642 rotary instruments than stainless steel K-files at the mid-root and coronal levels (mid-root: P < 0.05 and coronal: P < 0.001). Hero 642 rotary instruments had better centreing ability than K-files at all three levels (apical: P < 0.05, mid-root: P < 0.05 and coronal: P < 0.001). CONCLUSIONS: Hero 642 rotary instruments transported canals less, especially at the middle and coronal thirds of the root canals than stainless steel K-files. Hero 642 instruments had better centreing ability.     

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目的    研究根管冠部预处理对预备磨牙弯曲根管根尖偏移的影响。方法    从2006—2008年就诊于沈阳市口腔医院颌面外科121例患者因牙周病拔除的135颗磨牙中选取72个12  ~ 35°的弯曲磨牙根管，按照Schneider测量根管弯曲方法分成中度弯曲组（12  ~ 20°）和重度弯曲组（21 ~ 35°），每组36个根管，各组再按随机原则分为试验组和对照组，各18个根管。试验组：根管冠部用GG钻预处理，常规用10 ~ 35号不锈钢K锉进行根管预备；对照组：直接行常规法根管预备。记录各组根管预备至不同锉号时的根管影像，测量并比较各组不同锉号预备后的根尖偏移指数（ATI）。结果    中度弯曲组和重度弯曲组中，经冠部预处理的试验组ATI均明显小于对照组，差异有统计学意义（P < 0.05）；随锉号的不断增大，根尖偏移指数也逐渐增大，且试验组根管侧穿数明显小于对照组。结论    磨牙弯曲根管预备时经冠部预处理的根管预备效果优于常规处理。     

Curved molar root canal preparations using Hero 642 rotary nickel–titanium instruments

AIM: The Bramante method was used to study how the natural curvature of root canals was modified when using the Hero 642 nickel-titanium rotary system. METHODOLOGY: Twenty-four canals were selected in freshly extracted human mandibular molars. Every root canal had an angle of curvature greater than 20 degrees. Roots were embedded in clear casting resin using a plaster mould. Cross-sectional cuts were made in the apical, middle and coronal thirds of each root. A first group (control) of 12 curved root canals was prepared using stainless steel hand instruments and the step-back technique. A second group of 12 curved root canals was instrumented using the Hero sequence according to the manufacturer's instructions. For each sectioning level, the amount of dentine removed, the change of shape factor and the canal centre displacement were calculated with the aid of a digital image analysis system. The results were subjected to the Mann-Whitney U-test. RESULTS: No significant difference occurred in the amount of dentine removed, change of shape factor or canal centre displacement in the coronal and middle thirds of the curved canals. In the apical third, transportation was significantly higher (P=0.0171) with stainless steel hand instruments than with the Hero system. CONCLUSIONS: The original canal shape was maintained better in the apical third of curved canals when using the Hero system in a crown-down technique when compared to a hand preparation technique with stainless steel instruments.     

Root canal instruments for manual use: a review

Abstract Root canal instruments can be subdivided into instruments made of different alloys (stainless steel, nickel–titanium and nickel–aluminium) and instruments with different geometric forms (e. g., instruments with short cutting segments). Several types of stainless steel and titanium-based instruments are presented and assessed by a review of the current literature. In summary, flexible stainless steel instruments with noncutting tips seem to be a decisive improvement in the development of an ideal root canal instrument. They are superior to titanium–based instruments in both cutting efficiency and instrumentation of curved root canals.     

不锈钢K锉预备弯曲根管时根管不良形态形成的实验研究

目的:探讨弯曲根管预备时根管不良形态形成的特点与规律。方法:使用手用不锈钢K锉,按逐步后退法预备8个弯曲人工根管,根管预备过程中对根管及根尖孔进行微距摄影,用图像分析软件Image-ProPlus对根管的形态与位置变化进行测量、分析;实验数据采用SPSS10.0统计软件包进行统计学分析,选用配对t检验比较组间差异。结果:根管预备完毕,根管弯曲角度均值从预备前的36.21°(Schneider法)逐渐减小至21.98°,弯曲半径均值从6.28mm增大至11.35mm;根管长轴发生了偏移,与预备前原根管长轴形成2个交点,3个相交区。根管的连续锥度被破坏,并出现一系列预备缺陷。结论:弯曲根管预备时,根管器械在弯曲应力与切削力的共同作用下发生动态的根管偏移,是导致一系列根管不良形态的根本原因。     

Endodontic hand instruments: cutting efficiency, instrumentation of curved canals, bending and torsional properties

Abstract In an assessment of the usefulness of different root canal instruments, two aspects are of particular interest for the endodontist: the cutting efficiency of the instruments and their ability id enlarge curved canals without undesirable changes of the canal shape such as the formation of zips and elbows. This review paper is based on own investigations on the cutting efficiency and instrumentation of curved canals. Additionally, two parameters which are described in ISO 3630-1, resistance to bending and resistance to fracture, are discussed. With regard to cutting efficiency in rotary motion, flexible stainless steel reamers and K-files clearly display the best results and are superior to conventional stainless steel as well as titanium-based reamers and K-files. Regarding cutting efficiency in linear motion, stainless steel Hedström files made by certain manufacturers are significantly superior to stainless steel and titanium-based Hedström files of other brands. Flexible stainless steel instruments with modified noncutting lips clearly produce the best canal shape in curved canals. With only rare exceptions, all the instruments tested fulfilled the requirements of the ISO standard concerning resistance to fracture and resistance to bending.