纤维桩和金属桩修复喇叭状残根抗折性研究

目的：比较纤维桩和铸造金属桩修复重塑后喇叭状残根的抗折性能。方法：选择离体上颌中切牙16个,分为A、B两组,每组各8个,将标本制备成喇叭状根管,并用复合树脂重塑根管。A组用铸造金属桩核修复,B组用纤维桩及复合树脂核修复。两组标本经铸造全冠修复后,放置在电子万能试验机上,与牙长轴135°方向静态加载,直至牙齿折裂,记录加载负荷和折裂模式。结果：铸造桩核组的折裂强度为（0．591±0．094）kN,纤维桩组的折裂强度为0．489±0．081kN,经统计学处理,差异有显著性（P〈0．05）。铸造桩核组8个中6个为破坏性修复;纤维桩组均为可修复性折裂。经统计学处理,两组有显著性差异（p〈0．05）。结论：喇叭状残根经根管重塑后,选择纤维桩联合复合树脂核修复更有利于保护薄弱残根。     

根管重塑对薄弱根管抗折性能影响的实验室研究

目的探讨根管重塑对薄弱根管抗折能力的影响。方法收集成人离体牙30例作为样本,分为三组:实验组A、B和对照组每组各10例,实验组A、B组制备成喇叭口状根管,其中实验组B以复合树脂材料对薄弱根管进行重塑,三组样本分别铸造桩核冠修复,在电子万能力学试验机上沿与牙长轴135°方向静态加载,至牙体折裂,记录此时样本所承受的最大负荷,并对实验结果进行单因素方差分析两两比较。结果用复合树脂加强薄弱根管后修复组抗折裂强度与薄弱根管直接修复组差异有显著性,与对照组之间差异无显著性,薄弱根管直接桩核冠修复组与对照组之间的差异有显著性。结论利用复合树脂材料对薄弱根管进行根管重塑后修复,可提高其抗折能力。     

不同桩核系统及根管重塑对漏斗形根管下颌前磨牙抗折特性的研究

目的探讨不同桩核及根管重塑对漏斗形根管下颌前磨牙抗折特性的影响。方法将36颗离体下颌前磨牙随机分为A、B、C、D共4组,每组9颗。A、B、C组设为实验组,预备成漏斗形根管,A组用预成玻璃纤维桩复合树脂核修复,B组用预成钛合金平行螺纹桩复合树脂核修复,C组用复合树脂根管重塑铸造桩核修复;D组（对照组）采用正常根管预备,行铸造桩核修复。桩核修复后,4组均行铸造全冠修复。在电子万能试验机上以与牙体长轴成30°方向,以1 mm·min-1速度加载至样本折裂,分析4组样本的抗折载荷和折裂模式。折裂模式分为可修复性和不可修复性。对抗折载荷行单因素方差分析,对折裂模式采用Fisher′s确切概率法分析。结果A、B、C、D组的抗折载荷分别为（1.39±0.56）、（1.17±0.40）、（1.21±0.30）、（1.31±0.56）kN,4组间的差异无统计学意义（P>0.05）。A、B、C、D组产生不可修复性折裂的样本分别为6、8、9、9颗,4组间折裂模式的差异也无统计学意义（P>0.05）。结论不同桩核系统对下颌前磨牙漏斗形根管残根的抗折特性没有影响,复合树脂重塑可作为漏斗形根管残根修复的一种选择。     

复合树脂高强纤维桩核冠抗折性的实验研究

目的 探讨复合树脂高强纤维桩核冠的抗折性能,并与其他两种桩核冠的抗折性能进行比较.方法 收集30颗近期拔除的前磨牙,随机分为A、B、C3组,每组10颗牙.A组:复合树脂高强纤维桩核冠;B组:预成纤维桩核冠;C组:铸造镍铬桩核冠.常规根管治疗,桩道预备,铸造全冠修复.试件行5000次冷热循环和24万次循环加载,对完成循环加载的试件再行静态加载,至试件发生折裂,记录试件破坏时的载荷和折裂模式.结果 所有试件经过冷热循环和循环加载完好无折裂.试件破坏时载荷(N)为,A组:1100.5±351.9;B组:1182.0±226.1;C组:1539.7±445.8.A、B2组所有试件的折裂模式均为可再修复式折裂;C组中6个试件为可再修复式折裂,4个为不可再修复式折裂.结论 复合树脂高强纤维桩核冠的抗折强度和折裂模式与预成纤维桩核冠相近,折裂模式优于铸造桩核冠.     

上前牙薄弱根管重塑后桩核冠修复提高牙齿抗力的实验研究

目的　探讨桩核冠修复中提高薄弱根管抗力的方法。方法　选用成人离体牙 ,制备成喇叭口根管的实验样本 ,以BIS -CORE树脂材料对薄弱根管进行重塑 ,铸造桩核冠修复 ,在电子万能力学试验机上沿与牙长轴 135°方向静态加载 ,测试折裂强度。结果　用树脂加强薄弱根管后修复组折裂强度最高 ,与薄弱根管直接修复组差异有显著性。结论　利用BIS -CORE树脂材料对薄弱根管进行重塑后修复 ,可提高其抗力。     

桩和根管重塑材料对薄壁牙体抗折性能的影响

目的:探讨如何选择合适直径的桩和根管重塑材料,使薄壁根管获得更好的抗折性能。方法:选择90颗完整的上颌中切牙,完成根管治疗后,截冠分为9组。其中,4组进行常规桩道预备后行1.3 mm、1.6 mm镍铬合金铸造桩(A1.3和A1.6)和玻璃纤维桩(B1.3和B1.6)黏结后全冠修复,其余5组桩道扩大至根管壁为1 mm后行铸造桩核(C)和玻璃纤维桩修复,其中1.3、1.6 mm纤维桩用Rely X Unicem(D1.3和D1.6)和ParaCore(E1.3和E1.6)进行根管重塑和黏结,再用复合树脂堆核型后全冠修复,比较各组的抗折力和折裂模式。采用SPSS16.0软件包对数据进行统计学分析。结果:常规根管中,A1.3组获得最大的抗折力(610.2±45.6)N,A1.3、A1.6和B1.3、B1.6之间无显著差异(P>0.05)。薄壁根管中,C组获得最大的抗折力(584.5±121.2)N,而纤维桩经ParaCore重塑根管后可以增加牙体的抗折力[E1.3为(420.6±95.7) N,E1.6为(517.9±67.2) N],分别较D1.3和D1.6有显著差异(P<0.05),而与B1.3、B1.6无显著差异(P>0.05)。纤维桩修复的折裂模式中大部分可以重新修复,而金属桩大部分为破坏性。结论:纤维桩修复后,折裂的牙体大部分可以再次修复,1.3 mm和1.6 mm直径的桩对于牙体的抗折性无显著影响,ParaCore重塑根管可有效增强牙体的抗折性能。     

Bis-Core复合树脂重塑薄弱根管的临床应用

目的评价Bis—Core复合树脂重塑薄弱根管的临床疗效。方法对29颗薄弱根管的残根先用Bis—Core复合树脂重塑成正常形态，再进行常规桩核冠修复，随访6～20个月，观察牙根的折裂情况及桩核松动情况。结果所有牙根均未发生折裂，其中28颗桩核无松动，冠修复情况良好，有效率达96．55％，仅有1颗桩核松动脱落，修复失败。结论用Bis—Core复合树脂重塑薄弱根管，再以常规桩核冠修复，可以提高牙根的抗折能力。     

不同修复方法对邻[牙合]缺损的下颌前磨牙根管治疗术后抗折性能影响的研究

目的：比较不同修复方法对邻[牙合]缺损的下颌前磨牙根管治疗术后抗折强度的影响。方法：将50颗离体下颌前磨牙随机分为A、B、C、D、E五组,每组10颗。A组（对照组）：完整离体牙,不做任何处理。其它四组（实验组）样本牙经根管治疗并制备邻骀缺损。B组：光固化树脂直接充填;C组：树脂充填＋铸造全冠修复;D组：铸造桩核＋铸造全冠修复;E组：纤维桩树脂核＋铸造全冠修复。所有样本牙在电子万能试验机上以与牙体长轴成30°角、lmm／min速度加载直至样本折裂,记录样本折裂时的载荷数值与折裂模式,对数据进行统计分析。结果：A、B、C、D、E组的折裂载荷分别为（952．93±102．03）、（383．97±46．31）、（733．51±54．94）、（604．76±123．73）和（893．44±87．08）N。五组之间两两比较,只有A、E两组之间差异无统计学意义,其余差异均有统计学意义;A、B、C、D、E组产生不可修复性折裂（根折位于包埋树脂平面以下）的样本数分别为0、2、1、9、3,其中D组牙体的折裂模式与其它三组差异均存在统计学意义,剩余三组间两两比较差异无统计学意义。结论：纤维桩树脂核联合全冠修复可作为邻[牙合]缺损的前磨牙根管治疗术后的优选修复方式。     

三种方法修复薄弱根管冠方微渗漏的体外评价

目的评价可塑型纤维桩、预成纤维桩及根管重塑后预成纤维桩修复薄弱根管后的冠方微渗漏情况。方法选择正畸拔除上颌第一前磨牙36颗,制备形成薄弱根管。将30颗样本牙随机分为3组,A组可塑型纤维桩核系统修复、B组根管重塑后预成纤维桩核系统修复,C组预成纤维桩核系统修复,另外6颗为对照组。所有样本进行5℃-55℃冷热循环5000次后,置于0．5％碱性品红溶液中24h。将试件纵向剖开为2部分,在体视显微镜下观察各剖面修复材料与根管壁之间的微渗漏情况。用Kruskal—Wallisf法进行统计分析。结果3种方法修复后修复材料与根管牙本质之间均存在微渗漏现象,3组间无统计学差异（P〉0．05）。结论在本实验条件下,3种方法修复薄弱根管对冠方微渗漏的影响相近。     

可塑纤维桩修复对根管治疗牙抗折强度的影响

目的比较不同桩修复离体牙对修复体整体抗折强度的影响。方法将32颗上颌前磨牙行根管治疗并从唇侧釉牙骨质界上2 mm处截断后随机分为4组,A组采用镍铬金属铸造桩核加铸造冠修复,B组采用Tenax FiberWhite纤维桩、树脂核加铸造冠修复,C组采用EverStick可塑纤维桩单根（直径1.5 mm）、树脂核加铸造冠修复,D组采用EverStick可塑纤维桩双根（直径1.5 mm和1.2 mm）、树脂核加铸造冠修复。所有离体牙均由自凝树脂包埋,电子万能试验机加载头与牙体长轴成45°,以1 mm/min的加载速度加载直至试件任何部分折裂,记录读数并观察修复体折裂模式。结果A、B、C、D组间修复体的整体抗折强度差异无统计学意义（P>0.05）。各纤维桩组牙体折裂位置较铸造桩更接近牙颈部。结论尽管可塑纤维桩自身的弯曲强度较低,但是修复离体牙后整体抗折强度较高,可以满足临床要求。各纤维桩组折裂模式较铸造桩组更有利于修复体失败后的再修复。     

Preparation of simulated root canals using the Macfile, Canal Master U and K-Flexofile

The efficacy of three different root canal instruments in maintaining the original shape of curved canals was evaluated. Acrylic blocks were prepared to simulate canals with 40° and 60° curvature. K-Flexofiles and Macfiles were used with a step-back technique utilizing an 'in/out' filing motion. The balanced-force technique was used with Canal Master 'U' instruments. Ten 40° and 10 60° canals were prepared with each instrument. The results were evaluated using superimposed photographic slides at ×20 magnification to show the canals before and after the instrumentation. The width of the prepared canals was measured at their convex/concave point to determine the divergence of the instrumented canal shape from the original canal shape. The measurements were taken at the level of the apical foramen and 3 and 6 mm coronal to it. In this way it was possible to recognize all the defects created during the preparation of a canal. Among the tested instruments, the Macfile provoked minimal canal deviation ( P = 0.05). The Canal Master 'U' was similarly effective ( P = 0.05), but had the highest incidence of instrument fracture. The K-Flexofile demonstrated the most defects in canal preparation and canal deviation, particularly at the level of the apical foramen ( P < 0.01).     

Assessing the shape of root canals: an in vitro method using microradiography

The aim of this paper is to describe an in vitro method which provides clear and accurate details of root canal shape. The method utilizes the technique of contact microradiography to produce high resolution, two-dimensional, real-size images of canals in a longitudinal plane. Specimens can be accurately rotated through 90° allowing images to be produced in a bucco-lingual and mesio-distal direction. The method is simple, relatively rapid and can process large numbers of teeth without the need for complicated and expensive mounting blocks or film holders. The technique can be used to produce pre- and post-operative images of canal shape which can be superimposed to delineate the dentine removed during canal preparation. The method is thus suitable for the evaluation of the shaping ability of endodontic instruments and preparation techniques.     

切牙神经管的解剖学特点

目的　研究国人切牙神经管的位置及下颌管、颏管的关系 ,为临床手术提供解剖学数据。方法　据开 60侧湿下颌骨标本 ,对下颌管前端、颏管和切牙神经管进行直接观察和测量。结果　在下颌管前端分出颏管和切牙神经管。切牙神经管的管径为 1.76± 0 .2 6mm ,其下缘至下颌骨下缘的垂直距离为 9.5 3± 1.43mm ,始端对应颏孔前缘的水平距离为 3 .5 4± 0 .72mm。切牙神经管内为切牙神经 ,主要分布到下颌前牙。结论　颏管和切牙神经管由下颌管发出 ,颏管向后、上、外转弯上行 ,切牙神经管向前行     

连续横截离体牙对C形根管形态的研究

目的：研究C形根管根管口及横断面形态的变化。方法：收集具有C形根管解剖外形的上下颌第二磨牙、下颌智齿、下颌第一前磨牙206颗,用硬组织切片机从根管口向根尖方向每隔0.5 mm连续横切,在显微镜下观察其根管口及根管横断面形态的变化。根据Melton的方法进行分类。结果：206颗C形根管中,C1型根管口59颗,占28.64%;C2型为114颗,占55.34%;C3型33颗,占16.02%。根管横断面形态从根管口到根管中下段形态变化不定。结论：C形根管形态复杂多变,临床行根管治疗时难度较大。     

预备弯曲根管时根管偏移的实验研究

目的：定量研究弯曲根管预备过程中根管的偏移。方法：使用不锈钢K锉按常规法预备8个弯曲人工根管，根管预备过程中对根管、根尖孔进行微距摄影，用图像分析软件Image—Pro Plus对根管的形态和位置变化进行测量、分析。结果：根管预备时随着锉号的递增，弯曲根管逐渐被拉直，表现为根管弯曲角度逐渐减小，弯曲半径、根管轮廓面积逐渐增大，根管口、根尖孔被拉开，根管壁出现3个过度切削区。结论：预备弯曲根管时，根管不同部位的偏移方向、偏移距离并不相同，掌握弯曲根管的解剖形态以及根管器械的力学性能，有助于准确估计根管偏移的大小和方向。     

不同扩根器械拆除根管充填物的比较研究

目的比较不同器械在进行根管再治疗时拆除根管充填物的能力.方法选取48颗离体上前牙常规根管治疗后随机分为4组(每组12颗),进行根充物的拆除.记录到达工作长度牙数、到达工作长度用时、根充物推出根尖孔牙数、发生并发症牙数及器械损耗数.最后纵劈牙齿,统计根管内残余充填物量.实验结果采用ANOVA和X-检验.结果H锉联合回旋手机组到达根尖工作长度用时最短,与其它组间存在显著性差异(P＜0.01);四组根管内都有充填物残余;根管冠、中1/3的清理效果各组间无显著性差异(P＞0.05),而在根尖1/3处H锉联合回旋手机组的清理效果好,与其它组间存在显著性差异(P＜0.05);K锉联合回旋手机组有侧穿发生.结论H锉拆除根充物速度快、清理效果好;联合使用回旋手机可提高工作效率,但有一定的潜在风险,应谨慎操作.     

CLEANING ABILITY OF CHLORHEXIDINE GEL AND SODIUM HYPOCHLORITE ASSOCIATED OR NOT WITH EDTA AS ROOT CANAL IRRIGANTS: A SCANNING ELECTRON MICROSCOPY STUDY

The aim of this study was to evaluate the cleaning efficacy of 2% chlorhexidine gluconate gel (CHX) compared to 2.5% sodium hypochlorite solution (NaOCl) associated or not with 17% EDTA used as irrigants during the biomechanical preparation. Fifty freshly extracted single-rooted human teeth with complete apex formation were randomly divided into five groups: G1 - sterile saline, G2 - 2.5% NaOCl, G3 - 2% CHX, G4 - 2.5% NaOCl + EDTA and G5 - 2% CHX + EDTA. The specimens of G1 were subdivided into two control groups. The teeth were decoronated and the coronal and middle root thirds were prepared with Gates-Glidden burs, and the apical third was reserved to manual instrumentation. All procedures were performed by a single operator. In all groups, 2 mL of irrigant was delivered between each file change. The teeth were sectioned and prepared for analyses under scanning electron microscopy (SEM). SEM micrographs were graded according to a score scale by two examiners. Data were analyzed statistically by Kruskal-Wallis and Dunn tests at 1% significance level. The best results were obtained in the groups in which the irrigant was used followed by the chelating agent. No statistically significant difference was observed among G4, G5 and the positive control group (p<0.01). The groups G2 and G3 were significantly different from the others, presenting the worst cleaning capacity. In conclusion, the use of the chelating agent is necessary to obtain clean canal walls, with open tubules and no heavy debris. The use of 2% chlorhexidine gluconate gel alone is not able to remove the smear layer.     

223例阻塞根管的根管预备路径分析

目的 通过对223例阻塞根管进行根管预备的分析,总结出对阻塞根管预备的有效方法和一般规律.方法 将阻塞根管223例根据阻塞原因分成根管钙化、塑化治疗、根管治疗、其他治疗和器械折断5组,应用机械预备加化学预备、超声根管预备以及溶塑剂、溶根充等处理,配合探寻锉预弯、截短等技巧的使用进行根管预备,将预备结果分组记录,并进行统计分析.结果 223例阻塞根管预备成功209例,获得较高的成功率(93.7%).其中根管钙化组成功率93.2%;塑化治疗组成功率87.2%;根管治疗组成功率97.7%;其他治疗组成功率93.3%;器械折断2例均获得成功,其中塑化治疗组成功率低于根管治疗组(P＜0.05).结论 手持器械预备加化学预备,以及超声预备辅以探寻锉预弯、截短等技巧,用于阻塞根管的预备可获得满意的结果,塑化治疗再预备的成功率较低.     

超声技术应用于弯曲细小和堵塞根管的治疗分析

目的对弯曲、细小和堵塞根管的处理方法和疗效作出评价。方法应用超声技术对７３例弯曲、细小和堵塞根管的处理进行临床观察分析。结果根管扩大并完成根管充填６９例，成功率９４．５％，未出现牙折、侧穿、断锉等情况；失败４例，均为堵塞根管。结论证实了超声根管治疗的有效性、安全性和实用性，但在处理弯曲根管方面由于其成形作用较差，故尚有一定的局限性。     

Root and canal morphology of the mesiobuccal and distal roots of permanent first molars in a Kuwait population--a clinical study

Aim To identify the number of roots and canal configurations in permanent first molars of the indigenous Kuwaiti sub‐population and compare them against a similar group of non‐Kuwaiti population in different age groups and gender, and to determine the frequency of a second canal in the mesiobuccal root of maxillary first molars and distal root of mandibular first molars that could be located and treated in routine practice without using magnification or special lighting conditions. Methodology A total of 220 permanent first molar teeth of patients scheduled for root canal treatment over a period of 1 year were included. Patients were identified and grouped according to their nationality as Kuwaiti and non‐Kuwaiti (which included Filipinos, Indonesian Indians, Srilankans, Egyptians, Saudi Arabians and Syrians). In both nationality groups, patients were successively distributed into four groups based on their age. The first age group included patients below 20 years, the second 21–30 years, the third 31–40 years and the fourth were over 40 years. The first three groups comprised of 15 male and 15 female patients whilst the fourth group had 10 patients of each gender. Teeth with open apices, resorptions and calcification were excluded from the study. The teeth included were both clinically and radiographically examined for number of roots, the canal configuration and the presence of the additional mesiobuccal and distal canals and recorded. The simplified classification of canal configurations proposed by Weine was utilized. Results The incidence of a second canal in the mesiobuccal (MB) root of maxillary first molars and the distal root of mandibular first molars was not influenced significantly by nationality and gender. All the 110 maxillary first molars treated had three roots; 58% of MB root had one canal and 42% had two canals. The majority of the mesial roots had Weine type II canal configuration when the second mesiobuccal canal was present. All distobuccal and palatal roots had a single or type I canal configuration. Of the 110 mandibular first molars that were treated, 96% had two roots and 4% had three roots. When present, the third root was located either buccal or lingual to the main distal root. Overall 51% of the single distal roots had one canal whilst 49% had two canals. The mesial root frequently had a Weine type II canal configuration as did the distal root when a second canal was present. Pearson’s correlation analysis of both molars revealed a significant (P < 0.05) negative correlation (r = ?0.274, r = ?0.144) between age and number of canals as well as the type of canal. Conclusions The incidence of a second canal in distal roots of permanent mandibular first molars was 49% in the Kuwaiti population and this was similar to other Asian ethnic populations. Adopting modified access and troughing procedures revealed a 42% frequency of MB2 canals in maxillary first molars. The incidence of a second canal in both mesiobuccal roots of maxillary molars and distal roots of mandibular molars decreased significantly with age; no differences were noticed amongst the nationalities and gender studied. The possibility of extra roots should be anticipated in mandibular molars.