上颌第一前磨牙根管预备后根管壁厚度的研究

上颌第一前磨牙的牙根解剖形态较复杂 ,多有双分叉根、根面沟和近中凹面[1] 。所以根管预备后 ,根管壁厚度变薄 ,可能出现牙本质壁薄弱 ,甚至根折 ,将影响根管治疗术后修复效果。本实验对上颌第一前磨牙根管预备后 ,根管壁厚度进行测量研究 ,以对根外形有更多的了解。1　材料和方法10 6个上颌第一前磨牙 ,于釉牙骨质界最高点截去牙冠。然后作根管预备 ,根管工作长度距根尖 2ｍｍ[2 ] ,用ＴＲ -ＺＸ电动旋转根管锉预备根管至 # 40 ,用 3 0ｍＬ/Ｌ过氧化氢液和生理盐水交替冲洗 ,吸干 ,氧化锌丁香油糊剂加牙胶尖侧方加压充填根管 ,氧化锌丁香…     

即刻桩腔预备对三种根管预备方法预备的直根管根尖封闭性的影响

目的 研究三种不同根管预备方法根管预备、根管充填后即刺桩腔预备对直根管根尖封闭性的影响.方法 离体直单根管上前牙124个,其中120个随机平均分为3组(n=40),A组:不锈钢根管锉常规法;B组:G 型钻根管冠部预处理 不锈钢根管锉常规法;C组:手用Pr01raper镍钛根管锉冠向下法,刺余4个随机平均分为阴性对照组和阳性对照组.所有根管均用侧方加压法充填,即刻手持垂直加压器去除部分充填材料,然后P型钻桩腔预备.用染料渗透法评价各组根尖封闭能力.结果 B组G型钻根管冠部预处理 不锈钢根管锉常规法预备的根管和C组手用ProTaper镍钛根管锉冠向下法预备的根管即刻桩腔预备后,其根尖微渗漏较A组常规法预备的轻(P<0.05).结论 大锥度根管预备,根管充填后即刻桩腔预备的根尖封闭性较好.     

不同根管预备方法对直根管即刻桩腔预备根尖封闭性影响的研究

目的观察直根管不同根管预备方法根管充填后即刻桩腔预备对根尖封闭性的影响。方法离体直单根管上前牙84个,其中80个按根管预备方法随机平均分为2组(n=40),A组:不锈钢根管锉常规法;B组:G型钻根管冠部预处理+不锈钢根管锉常规法,其余4个随机平均分配为阴性对照组和阳性对照组。所有根管均用侧方加压法充填,即刻垂直加压器去除部分充填材料,然后P型钻桩腔预备。用染料渗透法评价各组根尖封闭能力。结果B组的根管进行即刻桩腔预备后,其根尖微渗漏较A组轻(P<0.05)。结论大锥度根管预备,根管充填后即刻桩腔预备根尖封闭性较好。     

第一前磨牙桩道预备后剩余根管壁厚度的研究

目的 采用解剖学方法,测量第一前磨牙桩道预备前后根管壁厚度,指导临床合理选择桩道预备器械.方法 收集上下颌第一前磨牙各30颗作为实验样本,用游标卡尺测量原始及分别用1、2、3号P型钻桩道预备后末端剩余根管壁的厚度.结果 牙根各项指标测量值均呈正态分布,对于双根管上颌第一前磨牙和单根管下颌第一前磨牙,3号P型钻预备后,近...     

比较2种根管充填糊剂对根尖封闭性的作用

目的用染料渗透法测量根管微渗漏的程度,比较2种根管充填糊剂在根管充填后不同时间进行桩腔预备后对根尖部的封闭能力。方法选取90颗成人的上颌中切牙,逐步后退法预备根管,侧向加压技术充填根管,充填剂分别用Cortisomol糊剂（A组）和氧化锌丁香油糊剂（B组）,每组45颗上颌中切牙。根据根管充填后桩腔预备时间将A组上颌中切牙随机分为A1组、A2组和A3组,每组15颗,A1组为根管充填后即刻进行桩腔预备,A2组为根管充填后2周进行桩腔预备,A3组为根管充填后4周进行桩腔预备。根据根管充填后桩腔预备时问将B组上颌中切牙随机分为B1组、B2组和B3组,每组15颗,B1组为即刻进行桩腔预备,B2组为根管充填后2周进行桩腔预备,B3组为根管充填后4周进行桩腔预备。进行桩腔预备后用染料渗透法评价各组根尖渗透能力。结果Cortisomot组（A组）与氧化锌丁香油组（B组）在根管充填后相同时间进行桩腔预备后,根尖微渗漏的差异具有统计学意义（P〈0．01）。A组在根管充填后即刻、2周、4周时进行桩腔预备,其根尖微渗漏的差异具有统计学意义（P〈0．01）。B组在根管充填后即刻、2周、4周时进行桩腔预备,其根尖微渗漏的差异无统计学意义（P〉0．05）。结论Cortisomol根管充填糊剂的封闭作用效果比氧化锌丁香油糊剂好。     

上颌前磨牙桩道预备后剩余根管壁厚度和抗折强度的研究

目的:探讨上颌前磨牙桩道预备后剩余根管壁厚度及对抗折强度的影响。方法:对100颗单、双根管上颌 前磨牙,用1#～5#P型钻进行桩道预备,用光学显微镜分别测量各组牙冠方和根方剩余根管壁厚度,并观察桩道预 备对抗折强度的影响。结果:单根管上颌前磨牙,1#～2#P型钻预备后,各壁剩余厚度均大于1mm;而对于双根管 上颌前磨牙,1#～3#P型钻预备后,各壁剩余厚度均大于1mm。另外,1#～5#P型钻预备后,牙根抗折强度逐渐变小 (P 0.01),且相同直径器械预备后,双根管抗折强度大于单根管(P 0.01)。结论:用P型钻预备桩道时,单根 管牙最大可用2#P型钻预备,双根管牙最大可用3#P型钻预备,且剩余牙质的量与牙齿的抗折强度成正相关。     

上颌第一磨牙不同根管预备方法的三维影像分析

目的:通过建立上颌第一磨牙模型,三维分析根管预备后根管中心的偏移。方法:7个离体上颌第一磨牙,随机分为2组。ProTaper预备组(n=4)和K锉预备组(n=3),根管预备前和预备后行Micro-CT扫描,建立三维模型及根管中心线模型,比较预备前、后根管中心线之间的三维空间距离。统计分析采用t检验。结果:建立了上颌第一磨牙的三维模型及根管中心线模型,腭根和近颊根管距离根尖1 mm层面上,Pro-Taper组根管中心线偏移明显小于K锉组,远颊根管距离根尖2 mm层面上,K锉组根管中心线偏移明显小于ProTaper组(P<0.05)。结论:上颌第一磨牙三维模型及根管中心线模型的建立,能三维测量、比较根管预备后的中心偏移,为根管预备效果的评价提供有效的量化数据参考。     

桩腔预备后剩余充填材料封闭根管能力的实验研究

目的:采用葡萄糖微渗漏模型检测桩腔预备后剩余充填材料封闭根尖的能力。方法:选取70颗单根管上颌前牙,随机分为4个实验组和2个对照组。采用逐步后退技术预备根管,AHp lus糊剂和牙胶尖侧向加压充填根管,然后G钻进行桩腔预备。实验组根管内剩余充填物长度分别为3、5、7、10 mm。用葡萄糖微渗漏模型检测第1、2、3和4周根管冠根向渗漏出的葡萄糖量。结果:实验第1周各组的葡萄糖微渗漏值无显著性差异(P>0.05),第2周起,第1组的微渗漏值高于第3、4组(P<0.05),而第1、2组之间无显著性差异(P>0.05)。结论:在保证桩核固位的前提下,应尽量多的保留根管内剩余充填物的长度。     

现代根管预备技术

根管预备是决定根管治疗质量的关键步骤．其目的是彻底清除根管系统内的有机残渣、微生物和感染牙本质．成形根管至根尖部的牙本质一牙骨质界处．预备成遵循原有根管形态的流畅锥形以利于根管冲洗、消毒和严密的三维充填。     

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。     

Residual dentin thickness in bifurcated maxillary first premolars after root canal and post space preparation with parallel-sided drills

STATEMENT OF PROBLEM: The primary factor that determines the prognosis of endodontically treated and restored teeth is preservation of sound dentin. The potential of these teeth to fracture is directly related to the amount of dentin removed. PURPOSE: The purpose of this study was to measure residual dentin thickness of bifurcated maxillary first premolars, in vitro, after root canal and conservative post space preparation. MATERIAL AND METHODS: Human premolars (n=13) with bifurcation at the junction of cervical and middle root thirds were embedded in a muffle device and horizontally sectioned 2, 4, and 6 mm apically to the cement-enamel junction. Residual dentin thickness was measured at the buccal, lingual, mesial, and distal aspects, apically to the bifurcation, and at the buccal or lingual, mesial, and distal aspects, coronally to the bifurcation. This procedure was repeated at baseline, after endodontic preparation (K-40 file), and after preparing the post space (ParaPost drills Nos. 3 and 4). Residual dentin thickness was analyzed using 3- or 4-way repeated measures ANOVA (alpha=.05). RESULTS: Endodontic therapy and post preparation reduced more dentin in the bifurcation aspects of both roots compared to outer aspects (P=.001). Post space preparation jeopardized the roots due to a residual dentin thickness of less than the recommended minimum 1-mm thickness in 61% (lingual) and 77% (buccal) of roots. CONCLUSIONS: Lack of residual dentin thickness after post preparation implies that the use of posts in maxillary first premolars should be limited. When mandatory, it is recommended that the lingual root be used and the buccal root be avoided.     

The effect of maintaining apical patency on canal transportation

Aim To evaluate, ex vivo, the effect of maintaining apical patency on the original canal shape during preparation of curved roots by two different techniques. Methodology Forty extracted human maxillary and mandibular molars were evaluated. Occlusal surfaces were ground and roots sectioned to the level of the cemento‐enamel junction to allow only one root to remain for evaluation in each tooth. Specimens were divided into four experimental groups (10 canals each): Group 1 – root canals prepared using the balanced force technique with stainless steel K‐files, and patency established with size 10 K‐files between each instrument; Group 2 – same as Group 1 but without the use of a patency file; Group 3 – canals instrumented with LightSpeed® instruments and patency established with size 10 K‐files between each instrument; and Group 4 – same as Group 3 but without the use of a patency file. Specimens were mounted and a series of radiographs taken. Initial and post‐preparation digital images were superimposed and the distance between two central axes at 1, 2 and 4 mm from the working length (WL) was measured to obtain an indication of the degree of apical transportation. Results were subjected to statistical analysis using two‐way analysis of variance (anova ). Results No significant differences were found in degree of apical transportation at different levels of the root canal (P > 0.05) nor in loss of WL between groups (P > 0.05). Conclusion In this laboratory study, maintaining apical patency did not influence canal transportation in the apical 4 mm.     

手用ProTaper镍钛锉与不锈钢H锉根管预备的临床疗效

目的比较手用ProTaper镍钛锉与标准手用不锈钢H锉根管预备的临床疗效。方法选择100例患者需作根管治疗的120颗患牙随机分为实验1组和实验2组,每组60颗患牙。实验1组使用标准手用不锈钢H锉和逐步后退法预备根管;实验2组使用手用ProTaper镍钛锉和冠向下预备技术预备根管。根管治疗完成后,随访3个月,观察临床疗效。结果实验2组根管治疗后疗效明显优于实验1组,其差异有统计学意义(P<0.05)。结论手用ProTaper锉系统柔韧性好,治疗成功率高,值得临床推广应用。     

Residual dentin thickness in mandibular premolars prepared with gates glidden and ParaPost drills

STATEMENT OF PROBLEM: The main factor that determines the prognosis of restored pulpless teeth is preservation of sound dentin. PURPOSE: This study evaluated the residual dentinal thickness (RDT) of mandibular premolars after preparation of post space with Gates Glidden and ParaPost drills. MATERIAL AND METHODS: Twelve extracted single canal mandibular premolars were embedded in clear polyester resin to the cementoenamel junction (CEJ) in a muffle device. Three horizontal sections were made 1, 3, and 5 mm apical to the CEJ. Mesiodistal (MD) and faciolingual (FL) axes were carefully marked and the RDT was measured for each slice. Each tooth slice was reassembled in the muffle device with orientation pins, then secured with stabilizing pins. This procedure was repeated after enlarging the root canal to K-40 file and preparing the coronal root canal space with Gates Glidden drills and ParaPost drills Nos. 3, 4, and 5. RESULTS: Residual dentinal thickness in a MD direction was 3.77 +/- 0.51 mm in the unprepared upper slice and 2.23 +/- 0.31 mm in the No. 5 ParaPost drill prepared lower slice, for a difference of 41%. The corresponding values for the FL direction were 4.35 +/- 0.51 mm and 4.08 +/- 0.46 mm, respectively (6%). CONCLUSION: The average dentinal thickness 5 mm below the CEJ in the mesial and distal directions after post space preparation approached the accepted minimal 1 mm. A conservative approach to post space preparation was advocated.     

机用镍钛器械TF和Protaper用于根管治疗的临床比较

目的:比较机用镍钛器械TF和Protaper用于根管治疗的临床效果。方法:随机选择牙髓炎或根尖周炎需进行根管治疗的患牙90颗,均分为3组:T组使用镍钛器械TF,冠向下技术预备根管;P组采用镍钛器械Protaper,冠向下技术预备根管,以上两组均采用热牙胶垂直加压技术充填根管;K组使用不锈钢K锉,逐步后退法预备根管,冷牙胶技术侧向加压技术充填。记录根管预备时间及器械折断数,根据治疗前、中、后的X线片评价根管预备及根充效果。结果:T组、P组均能保持根管原有走向,形态未改变,操作时间均短于K组,P组3例发生器械折断,T组未发生器械分离,结论:TF与Protaper预备根管根管成形好,时间短,根充效果好,TF相对于Protaper更适合于弯曲根管的预备。     

In vitro comparison of root canal preparation with step-back technique and GT rotary file--a nickel-titanium engine driven rotary instrument system

The aim of the authors' study was to compare the remaining root canal wall thickness and the preparation time of root canals, prepared either with step-back technique, or with GT Rotary File, an engine driven nickel-titanium rotary instrument system. Twenty extracted molars were decoronated. Teeth were divided in two groups. In Group 1 root canals were prepared with step-back technique. In Group 2 GT Rotary File System was utilized. Preoperative vestibulo-oral X-ray pictures were taken from all teeth with radiovisiograph (RVG). The final preparations at the mesiobuccal canals (MB) were performed with size #30 and palatinal/distal canals with size #40 instruments. Postoperative RVG pictures were taken ensuring the preoperative positioning. The working time was measured in seconds during each preparation. The authors also assessed the remaining root canal wall thickness at 3, 6 and 9 mm from the radiological apex, comparing the width of the canal walls of the vestibulo-oral projections on pre- and postoperative RVG pictures both mesially and buccally. The ratios of the residual and preoperative root canal wall thickness were calculated and compared. The largest difference was found at the MB canals of the coronal and middle third level of the root, measured on the distal canal wall. The ratio of the remaining dentin wall thickness at the coronal and the middle level in the case of step-back preparation was 0.605 and 0.754, and 0.824 and 0.895 in the cases of GT files respectively. The preparation time needed for GT Rotary File System was altogether 68.7% (MB) and 52.5% (D/P canals) of corresponding step-back preparation times. The use of GT Rotary File with comparison of standard step-back method resulted in a shortened preparation time and excessive damage of the coronal part of the root canal could be avoided.     

上颌乳前牙根管形态及根部牙本质力学性能的测定

目的 测量上颌乳前牙根管锥度、直径及根部牙本质的弹性模量和硬度,为用于上颌乳前牙的可吸收根管桩的制作提供参考。方法 选择全身麻醉下进行上颌乳前牙根管治疗的患儿,采用硅橡胶制取上颌乳前牙根管印模,扫描印模后测量根管的锥度和直径。收集10颗离体上颌乳前牙,测量根部牙本质的弹性模量和硬度。结果 本研究共收集了74颗上颌乳前牙的根管模型,其中乳中切牙28颗,乳侧切牙35颗,乳尖牙11颗。乳中切牙、乳侧切牙、乳尖牙的平均锥度依次为0.106、0.185、0.098,釉牙骨质界下方5 mm处平均直径依次为1.267、0.860、1.429 mm。10颗离体上颌乳前牙根部的牙本质弹性模量范围为19.919~25.017 GPa,硬度范围为0.867~1.082 GPa。结论 制作乳牙根管桩时,乳中切牙及乳尖牙根管桩建议取锥度为0.1,尖端直径为1.2、1.4 mm;乳侧切牙根管桩建议取锥度为0.2,尖端直径为0.8 mm;桩的弹性模量范围为20~25 GPa,硬度范围为0.87~1.08 GPa较为适宜。     

不同根管内壁处理方法对玻璃离子水门汀与根管牙本质粘接强度的影响

目的：评价不同根管内壁处理方法对树脂改性玻璃离子水门扪‘与根管牙本质粘接强度的影响。方法：新鲜拔除的42个完整前牙或单根管前磨牙，于釉一牙骨质界处水平截断，根据不同处理根管壁＋粘接纤维桩的方法随机分为7组：A组：无酸蚀＋GC Fuji I；B组：酸蚀＋GC Fuji I；C组：酸蚀＋singlebond2＋GCFujiI；D组：无酸蚀＋GCFuji ⅡLC；E组：酸蚀＋GC VujiⅡLC；F组：酸蚀＋singlebond2＋GCVujiⅡLC：G组：酸蚀＋singlebond2＋ClearfilDCCoreAutomix。粘结处理后垂直牙根长轴切割成1mm厚薄片，在万能测试机上进行微推出测试。结果：7组粘接强度分别为A组（1．6367±0．2673）MPa；B组（1．9933±0．1906）MPa；C组（2．4800±0．5349）MPa；D组（3．1967±0．7068）MPa：E组（3．9385±0．2782）MPa；F组（5．5317±0．5545）MPa；G组（8．2510±0．7757）MPa。D组、E组、F组均相应高于相同根管内壁处理方法的A组、B组、C组（p〈0．05），但均低于G组如〈O．05）；F组〉E组〉D组（P（0．05），ABC三组间无显著差异（p〉O．05）。结论：不同方法处理根管内壁对粘接材料与根管牙本质间的粘接强度有影响。