被动超声冲洗对弯曲根管的碎屑清理能力和根管形态的影响

目的: 评价被动超声冲洗在弯曲根管内碎屑清理能力和根管偏移量。方法: 选取下颌磨牙近中弯曲根管36个,弯曲度在25°以上,以机用 XP-endo Shaper根管锉预备根管。根据弯曲长度（curved length,CL）和冲洗方式分为A1组（CL>3 mm,注射器冲洗）、B1组（CL>3 mm,超声K锉冲洗）、C1组（CL>3 mm,irrisafe超声锉冲洗）、A2组（CL<3 mm,注射器冲洗）、B2组（CL<3 mm,超声K锉冲洗）和C2组（CL<3 mm,irrisafe超声锉冲洗）,每组6个样本。对所有样本冲洗前、后进行Micro-CT扫描,计算冲洗后根管内体积增加量和根管偏移量。采用SPSS 22.0软件包对数据进行统计学分析。结果: 在CL>3 mm的根管根尖区,PUI+irrisafe组的根管体积增量显著高于PUI+K锉和注射器冲洗（P<0.05）,并且在距离根尖孔5 mm处PUI+irrisafe形成的根管偏移量显著低于PUI+K锉（P<0.05）;与注射器冲洗相比无显著差异（P>0.05）。在CL<3 mm的根管中,PUI+irrisafe组和PUI+K锉组的根管体积增量均显著高于注射器冲洗（P<0.05）,但根管偏移量与注射器冲洗无显著差异（P<0.05）。结论: 在弯曲长度较大的根管中,被动超声冲洗结合预弯锉可获得更好的清理效果;而在弯曲长度较小的根管中,被动超声冲洗结合K锉和预弯锉均安全有效。     

Hero 642对弯曲根管根管成形能力的评价

目的：评价机用镍钛锉Hero 642预备弯曲根管时的根管成形能力。方法：利用自主研制的《牙齿模拟根管辅助分析测量系统》软件,定量检测8个模拟根管在用Hero 642以冠下法预备前后的形态变化,并进行统计学分析。结果：机用镍钛锉Hero 642能够很好地保持根管的原始弯曲度。在预备至0.02锥度25#銼和30#锉时,Hero 642对弯曲根管的各部位切割均衡,根管几何中心线基本不移位。结论：机用镍钛锉Hero 642具有良好的根管成形能力。对于高度弯曲的根管,预备主锉仍可选择0.02锥度30^#锉。     

根管预备锥度对根管桩固位力的影响的实验研究

目的:评价离体牙根管预备的不同锥度对根管桩固位力的影响.方法:成人离体上颌切牙40 颗,随机分为4 组,并按以下方法预备根管:A:SS(不锈钢手用k型锉)15~40#/0.02;B:PF(ProFile)OS 3#/0.06 PF 25#/0.06;C:PF OS 4#/0.07 PF 30#/0.06;D:PF OS 5#/0.08 PF 35#/0.06.垂直加压法充填根管尖部5 mm,直接法制作铸造镍铬合金根管桩,粘固48 h 后进行固位力的测试.结果:各组间的固位力均数不完全相同(P<0.05).A 组与B 组间的差异无显著性;A 组与C、D 组的差异均有显著性.结论:在一定锥度范围内,根管预备锥度的增大可增强根管桩的固位力.     

镍钛器械联合应用于磨牙弯曲根管预备的临床效果

目的 比较ProTaper联合镍钛K锉、S3锉、ProTaper锉3组镍钛器械在预备磨牙重度弯曲根管中的临床效果.方法 选取重度弯曲根管的磨牙150颗,随机分为3组(n=50个),分别使用ProTaper联合镍钛K锉(A组)、S3锉(B组)、ProTaper锉(C组)预备根管,侧压法充填根管,比较3组器械的根管成形效果、器械分离情况、术后疼痛反应情况.结果 3组器械预备根管后成形效果良好率分别为82.0％、86.0％、62.0％,A、B组两组器械的根管成形效果均优于C组,差异有统计学意义(P<0.05).B组的器械分离数最少,B组与C组差异有统计学意义(P<0.05).3组的术后疼痛反应发生率为分别6.0％、4.0％和4.0％,差异无统计学意义(P>0.05).结论 在磨牙重度弯曲根管中,ProTaper联合镍钛K锉和S3锉均有良好的临床效果.     

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。     

三种新型连续运动机用镍钛器械对重度弯曲模拟根管成形能力的体外研究

目的:比较3种新型连续运动机用热处理镍钛器械在重度弯曲模拟根管预备过程中的成形能力。方法:将18个树脂模拟根管随机分成3组(n=6),分别使用ROTATE^TM,ProTaper Next(下述PTN)及GPS-File Gold(下述GPS-Gold)机用镍钛锉预备根管,预备前后分别对树脂块进行micro-CT扫描,并计算预备前后根管全长及多个测量水平体积增量比、表面积增量比及根管偏移量,分析各镍钛锉的切削能力及中心定位能力。结果:GPS-Gold组在根上段及全长的体积和表面积增量比大于ROTATE^TM组(P<0.05),在根尖区体积和表面积增量比大于PTN组(P<0.05);ROTATE^TM组在根管最弯曲段造成根管向弯曲内侧偏移(P<0.05),GPS-Gold组在根尖段和根上段造成根管向弯曲外侧偏移(P<0.05);3组器械在根管偏移量上的组间差异均无统计学意义(P>0.05)。结论:3种镍钛器械对模拟弯曲树脂根管成形能力良好,可满足临床需求。     

Micro-CT评价WaveOne预备根管后根管偏移的实验研究

目的以Micro-CT为研究工具评价Wave One镍钛器械对根管偏移的控制能力和中心定位能力。方法将40颗离体前磨牙随机分为A、B、C、D 4组,Wave One(A组)、机用Protaper(B组)、手用Protaper(C组)3组采用根向技术预备根管;手用不锈钢K锉(D组)按照标准技术预备根管。预备前、后均用Micro-CT扫描并对近中、远中根管壁(双根管以颊侧根管计)的厚度进行测量,然后利用Gambill提出的公式进行根管偏移和轴中心率的计算。结果根管预备后根管偏移量:A组小于其它3组(P<0.05);轴中心率:A组大于其它3组(P<0.05)。结论 Wave One在预备根管时,能够较好的维持根管原始走向,减少根管中心的偏移,具有临床使用价值。     

相同横截面的单支锉弯曲根管成形能力的体外研究

目的:比较相同横截面的不同往复运动机用镍钛器械对模拟弯曲根管的预备成形能力。方法:采用42个树脂模拟重度弯曲根管，随机分成S形横截面组(A组)与平行四边形横截面组(B组)。A组树脂块随机分为3组(n=7),分别使用Reciproc Blue、O-Blue、O-Gold单支锉根管预备；B组树脂块随机分为3组(n=7),分别使用WaveOne GOLD、WF File(New)、WF File(Old)单支锉根管预备。预备后根尖直径0.25 mm。预备前后分别使用微计算机断层扫描(micro-computed tomography, micro-CT)扫描树脂块并计算根管全长及多个不同测量水平体积增量比、表面积增量比及根管偏移量。结果:在根尖段，O-Blue组体积增量比和表面积增量比大于Reciproc Blue组(P<0.01&P<0.05),表面积增量比小于O-Gold(P<0.05),O-Gold组体积增量比和表面积增量比大于Reciproc Blue组(P<0.001);在根中段，O-Blue的体积增量比大于O-Gold组(P<0.01);在根...     

大锥度根管预备混合法在树脂模拟弯曲根管中预备效率的研究

目的观察手用不锈钢K型锉与ProTaper手用镍钛锉联合应用的大锥度根管预备混合法的预备效率。方法采用树脂模拟根管60例,随机分为2组,大锥度根管预备混合法组(简称C组):手用不锈钢K型锉与ProTaper手用F2镍钛锉联合应用;Protaper手用镍钛锉序列组(简称P组)。比较其器械折断情况、操作时间、所用费用和根管预备效果。结果2组均形成冠方大、根端小的连续大锥形根管;C组无断针情况,P组断针率为10%;根管预备时间C组为平均6.37min,P组为平均11.32min(P<0.05);所用成本P组约为C组的4倍。结论大锥度根管预备混合法(C组)预备根管成形效果好,操作时间短,不易断针,且经济实用。     

机用镍钛锉去除根管旧充填物能力的体外研究

目的研究0.04锥度的镍钛锉去除根管旧充填物的能力.方法将30颗单根管前牙分成A、B、C三组,每组10颗.用K型锉行根管颈备、牙胶尖+氧化锌侧压法充填.放置30天后用不同的方法去除根管旧充填物A组为K型锉+氯仿组;B组为镍钛锉+氯仿组;C组为单纯应用镍钛锉组.记录操作时间、氯仿用量.将牙根纵劈,立体镜下观察牙根整体及其不同水平的残留物情况,将结果进行统计学分析.结果对于根管整体的残留物量,C组少于A组,存在显著性差异(P=0.007),其余的实验组间无显著性差异(P＞0.05).对于操作时间,B、C两组均少于A组(P＜0.05),B、C两组间无显著性差异(P＞0.05).B组的氯仿用量少于A组(P＜0.05).结论同K型锉相比,机用镍钛锉去除根管旧充填物更为完善且操作时间显著减少.     

Comparative study on the shaping ability and cleaning efficiency of rotary Mtwo instruments. Part 2. Cleaning effectiveness and shaping ability in severely curved root canals of extracted teeth

AIM: To compare the cleaning effectiveness and shaping ability of Mtwo, K3, and RaCe nickel-titanium rotary instruments during the preparation of curved root canals in extracted human teeth. METHODOLOGY: A total of 60 root canals of mandibular and maxillary molars with curvatures ranging between 25 degrees and 35 degrees were divided into three groups of 20 canals. Based on radiographs taken prior to instrumentation with the initial instrument inserted into the canal, the groups were balanced with respect to the angle and the radius of canal curvature. Canals were prepared using a low-torque control motor. Using pre- and post-instrumentation radiographs, straightening of the canal curvatures was determined with a computer image analysis program. The amount of debris and smear layer was quantified on the basis of a numerical evaluation scale. The data established for scoring the debris and the smear layer was separately recorded and analysed statistically using the Kruskal-Wallis test. RESULTS: During preparation no instrument separated. Completely clean root canals were never observed. For debris removal Mtwo instruments achieved significantly better results (P < 0.001) than K3 and RaCe instruments. The results for remaining smear layer were similar and not significantly different (P > 0.05). Mtwo instruments maintained the original canal curvature significantly better (P < 0.05) than the other instruments. Instrumentation with Mtwo files was significantly faster than with K3 or RaCe instruments (P < 0.05). CONCLUSIONS: Under the conditions of this study, Mtwo instruments resulted in good cleaning and maintained the original curvature significantly better than K3 or RaCe files.     

A comparison of three Ni-Ti rotary instruments in apical transportation

The purpose of this study was to compare apical transportation and changes in canal curvature of three nickel-titanium (Ni-Ti) rotary instruments: Hero 642, RaCe, and ProTaper. Mesiobuccal canals of 60 maxillary first molars (with angles of curvature between 25 degrees and 35 degrees) were prepared with a torque-control, low-speed engine. Canals were prepared using the crown-down technique to the size of #30. Using a radiographic platform, reproducible preinstrumentation and postinstrumentation radiographs were taken. A computer analysis allowed magnification and superimposition of the images. The central axes of initial and final instruments were radiographically superimposed to measure transportation at 1 mm from WL. Data were analyzed using repeated-measures ANOVA. A statistically significant difference in apical transportation was found in ProTaper group. The results suggest that ProTaper file system be implemented in combination with other less tapered more flexible systems, like RaCe, in preparing curved canals.     

The shaping effects of three nickel-titanium rotary instruments in simulated S-shaped canals

The purpose of this study was to compare the shaping effects of three nickel-titanium rotary instruments, ProTaper, K3, and RaCe, with emphasis on canal transportation. Simulated canals with an S-shaped curvature in clear resin blocks were prepared with a torque-control, low-speed engine. Canals were prepared using the crown-down technique to the size of #30. Canal aberrations were assessed by comparing the pre- and postinstrumentation images under a stereomicroscope. ProTaper instruments caused greater widening of canals compared to K3 or RaCe. Furthermore, ProTaper files showed a tendency to ledge or zip formation at the end-point of preparation. These canal aberrations may be caused by ProTaper finishing files, which appear to be less flexible than other files of the same tip-size, because of their greater taper-size. These results suggest that nickel-titanium file systems including less tapered, more flexible instruments, like K3 and RaCe should be used in the apical preparation of canals with a complicated curvature.     

Deformation and fracture of RaCe and K3 endodontic instruments according to the number of uses

AIM: To evaluate, by scanning electron microscopy, the deformation and fracture of NiTi RaCe and K3 size 25, 0.04 taper instruments. METHODOLOGY: Ten sets of instruments from RaCe and K3 NiTi rotary systems were used to prepare 100 simulated canals in epoxy resin blocks with 20 or 40 degree curvatures beginning 8 or 12 mm from the orifice. Each instrument set was used to prepare five simulated canals using a crowndown technique. The size 25, 0.04 taper instruments were analysed by SEM when new and again after each use. Three observers scored images of the instruments after each use for distortion of the spirals (no distortion, distortion of one spiral or distortion of more than one spiral), wear (no wear, small, moderate or severe wear) and fracture (yes or no). Two-way anova was used to analyse differences between instruments for distortion and wear; Fisher's exact test looked for differences related to fracture of instruments. RESULTS: No fractures occurred with K3 instruments, whereas six RaCe instruments fractured (P = 0.005). A statistically significant difference occurred between RaCe and K3 instruments in terms of distortion of spirals and surface wear (P < 0.001). Distortion of spirals and wear increased with progressive use of RaCe instruments, whereas K3 instruments remained relatively undamaged after their fifth use. The simulated canals with smaller radii of curvature were positively associated with fracture of RaCe instruments. CONCLUSIONS: A significant difference was found between RaCe and K3 in terms of deformation and fracture of size 25, 0.04 taper instruments; K3 instruments had more favourable results.     

Comparative investigation of two rotary nickel-titanium instruments: ProTaper versus RaCe. Part 2. Cleaning effectiveness and shaping ability in severely curved root canals of extracted teeth

AIM: To determine the cleaning effectiveness and shaping ability of ProTaper and RaCe nickel-titanium rotary instruments during the preparation of curved root canals in extracted human teeth. METHODOLOGY: A total of 48 root canals of mandibular and maxillary molars with curvatures ranging between 25 degrees and 35 degrees were divided into two groups of 24 canals each. Based on radiographs taken prior to instrumentation with the initial instrument inserted into the canal, the groups were balanced with respect to the angle and the radius of canal curvature. Canals were prepared using a crown-down preparation technique. After each instrument, the root canals were flushed with a 2.5% NaOCl solution and at the end of instrumentation with NaCl. Using pre- and post-instrumentation radiographs, straightening of the canal curvatures was determined with a computer image analysis program. After splitting the roots longitudinally, the amount of debris and smear layer was quantified on the basis of a numerical evaluation scale, using a scanning electron microscope (SEM). The data established for scoring the debris and the smear layer were separately recorded and analysed statistically using the Wilcoxon test. RESULTS: Two ProTaper and three RaCe instruments fractured; there was no significant difference between instrument types (P > 0.05). Completely clean root canals were never observed. For debris removal, RaCe files achieved significantly better results (P < 0.001) than ProTaper instruments. The results for remaining smear layer were similar and not significantly different (P > 0.05). RaCe instruments maintained the original canal curvature significantly better (P < 0.05) than ProTaper instruments. No significant differences were detected between the instruments (P > 0.05) for the time taken to prepare the canals. CONCLUSIONS: Under the conditions of this study, RaCe instruments resulted in relatively good cleaning and maintained the original curvature significantly better than ProTaper did.     

Comparative investigation of two rotary nickel-titanium instruments: ProTaper versus RaCe. Part 1. Shaping ability in simulated curved canals

AIM: To compare the shaping ability of ProTaper with Reamer with Alternating Cutting Edges (RaCe) instruments. Part 1 of this two-part report describes the efficacy of these two nickel-titanium instruments in simulated curved root canals. METHODOLOGY: Simulated canals with 28 degrees and 35 degrees curves in resin blocks were prepared with ProTaper and RaCe instruments using a crown-down preparation technique (n = 24 canals in each case). Pre- and postinstrumentation images were recorded, and assessment of canal shape was completed with a computer image analysis program. Material removal was measured at 20 measuring points, beginning 1 mm from the apex. Incidence of canal aberrations, preparation time, changes of working length and instrument failures were also recorded. The data were analysed statistically using the Mann-Whitney U-test or the chi-square test. RESULTS: On average, canals prepared with RaCe instruments remained better centred compared with those enlarged with ProTaper files. Three RaCe instruments and two ProTaper files fractured during preparation (P > 0.05). Between both the canal types, RaCe was significantly faster (P < 0.001) than ProTaper and maintained working length significantly better (P < 0.05). CONCLUSION: Both instruments prepared curved canals rapidly and were relatively safe. RaCe respected original canal curvature better than ProTaper, which tended to transport towards the outer aspect of the curve.     

Comparative study on the shaping ability and cleaning efficiency of rotary Mtwo instruments. Part 1. Shaping ability in simulated curved canals

AIM: To compare the shaping ability of Mtwo instruments with K3 and RaCe instruments. Part 1 of this two-part report describes the efficacy of these nickel-titanium instruments in simulated curved root canals. METHODOLOGY: Simulated canals with 28 degree and 35 degree curves in resin blocks were prepared with Mtwo instruments using a single length technique and with K3 and RaCe instruments using a crowndown preparation technique (n = 20 canals in each case). Pre- and post-instrumentation images were recorded and assessment of canal shape was completed with a computer image analysis program. Material removal was measured at 20 measuring points, beginning 1 mm from the endpoint of preparation. Incidence of canal aberrations, preparation time, changes of working length and instrument failures were also recorded. The data were analysed statistically using ANOVA and Student-Newman-Keuls test. RESULTS: On an average, canals prepared with Mtwo instruments remained better centred compared with those enlarged with K3 or RaCe instruments. Six RaCe instruments, four K3 files and none of the Mtwo instruments fractured during preparation (P > 0.05). In both of the canal types, Mtwo was significantly faster (P < 0.001). It was possible with all types of instruments to control working length as well. CONCLUSIONS: Mtwo instruments prepared curved canals rapidly, respected original canal curvature well and were safe to use.     

手用ProTaper器械预备弯曲根管的研究

目的 使用牙髓立体模型(Endodontic Cube)评价手用ProTaper预备不同弯曲根管的能力.方法 按纳入标准筛选离体牙样本,根据根管弯曲度(α)将根管分3组,A组0°≤α＜25°,B组25°≤α＜40°,C组40°≤α＜55°,每组18个根管.灌制Endodontic Cube模型,用低速锯将样本分为根管上、中、下段,组装模型,手用ProTaper预备根管,体视显微镜获取预备前、后根管的断面形态.统计学分析预备前后各段根管截面积之差AS、面积比、根管偏移距离X1、中心比CR值.结果 ①B、C组的牙本质切削量和预备前后根管截面积差比较大[B组根中部△S为(0.46±0.25)mm2,C组根中部△S为(0.48±0.30)mm2],显著大于A组[A组根中部AS为(0.28±0.13)mm2,P＜0.05];②C组的根管偏移距离最大,在根尖部[(0.23±0.10)mm]、根中部[(0.36±0.16)mm]及根上部[(0.31±0.15)mm]均显著大于A组[根尖部(0.19±0.07)mm、根中部(0.20±0.08)mm、根上部(0.18±0.08)mm,与C组相比P＜0.05],在根管中段的偏移距离显著大于B组[(0.28±0.11)mm,P＜0.05];③C组根管中部的维持能力显著差于A、B组(P＜0.01).结论 随着根管弯曲度的增加,手用ProTaper对牙本质的切削量增加,定位中心的能力降低.     

Comparison of root canal preparation using RaCe and ProTaper rotary Ni-Ti instruments

AIM: To compare various parameters of root canal preparation using RaCe (FKG Dentaire, La-Chaux-de-Fonds, Switzerland) and ProTaper (Dentsply Maillefer, Ballaigues, Switzerland) nickel-titanium (Ni-Ti) instruments. METHODOLOGY: Fifty extracted mandibular molars with mesial root canal curvatures between 20 degrees and 40 degrees were embedded in a muffle system. All root canals were prepared to size 30 using RaCe or ProTaper rotary instruments in low-torque motors with torque control and constant speed of 300 r.p.m. (ProTaper with ATR Tecnika, Advanced Technology Research, Pistoia, Italy; RaCe with EndoStepper, S.E.T., Olching, Germany). In both groups irrigation was performed with 2 mL NaOCl (3%) after each instrument size. Calcinase-Slide (lege artis, Dettenhausen, Germany) was used as a chelating agent with each instrument. The following parameters were evaluated: straightening of curved root canals, postoperative root canal cross-sections, safety issues and working time. Cleanliness of the root canal walls was investigated under the SEM using 5-score indices for debris and smear layer. Statistical analysis was performed using the following tests: Wilcoxon's test for straightening and working time was used (P < 0.05); Fisher's exact test for comparison of cross-sections and root canal cleanliness (P < 0.05). RESULTS: Both Ni-Ti systems maintained curvature well; the mean degree of straightening was less than 1 degrees for both systems. Following preparation with RaCe, 49% of the root canals had a round or oval diameter and 50% an irregular diameter, ProTaper preparations resulted in a round or oval diameter in 50% of the cases. For debris, RaCe and ProTaper achieved 47 and 49% scores of 1 and 2, respectively; there was no significant difference. For smear layer, RaCe and ProTaper achieved 51 and 33% scores 1 and 2, respectively; no statistically significant differences were apparent for the coronal and middle sections of the root canals, but RaCe performed significantly better in the apical region (Fisher's exact test, P = 0.0392). Two roots lost working length with RaCe instruments, whilst ProTaper preparation resulted in two roots loosing working length and one fractured instrument. Mean working time was shorter for ProTaper (90.9 s) than for RaCe (137.6 s); the difference was significant (Wilcoxon's test, P = 0.011). CONCLUSIONS: Both systems respected original root canal curvature well and were safe to use. Cleanliness was not satisfactory for both systems.     

冠部预处理对磨牙重度弯曲根管工作长度影响的研究

目的：观察根管冠部预处理对磨牙重度弯曲根管工作长度的影响。方法：选择磨牙根管弯曲度在25°～45°的牙髓炎、根尖炎的460颗患牙588个重度弯曲根管,随机分为A、B、C组,A组153颗磨牙192个根管不预处理冠部,手用不锈钢K锉逐步后退法预备根管,分别测量预备前、后根管长度;B、C组分别用GG钻、机用ProTaper成形锉进行冠部预处理后测量根管工作长度,之后B组151颗磨牙196个根管手用不锈钢K锉逐步后退法预备根管;C组156颗磨牙200个根管机用ProTaper器械完成锉预备根管,两组预备完成后测量根管长度,并对数据进行统计学分析。结果：A组磨牙重度弯曲根管预备前后长度有明显改变（P＜0．01）,B、C组经根管冠部预处理后长度改变差异无统计学意义（P＞0．05）。结论：磨牙重度弯曲根管冠部预处理后测量根管工作长度可以提高根管工作长度测量的准确性。