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).     

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.     

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。     

2种侧压器进入弯曲根管的深度及充填质量的比较

目的 比较镍钛（NiTi）侧方加压器和不锈钢（SS）侧方加压器进入不同程度弯曲根管的深度和根充质量。方法 选择40颗离体弯曲单根管的下颌前磨牙,依据根管弯曲度将其分为小于等于20°和大于20°。采用机用镍钛ProFile器械预备根管,测定2种侧压器进入有主牙胶尖根管的深度,并采用冷牙胶侧方加压充填技术充填根管,在距根尖2 mm和4 mm处对根管作水平片切,记录图像并分析根管中牙胶面积的百分比（PGP）。结果 在弯曲度大于20°的根管中,NiTi侧压器进入根管的深度及根尖2 mm处PGP均大于SS侧压器（P<0.05）;在弯曲度小于等于20°的根管中,二者的差异无统计学意义（P>0.05）。采用不同侧压器充填的根管距根尖4 mm处的PGP的差异均无统计学意义（P>0.05）。结论 NiTi侧压器在严重弯曲根管中较SS侧压器能获得较好的进入深度及充填质量。     

根管钙化治疗的研究进展

根管钙化是牙髓病和根尖周病临床治疗中较为棘手的问题.了解各类钙化根管的治疗方法,对提高治疗成功率有重要意义.yynw文就根管钙化的原因、X线摄片技术、钙化根管口的寻找方法及临床治疗的研究现状作一综述.     

根管治疗术中的疼痛原因分析及疼痛控制

根管治疗是牙髓病及根尖周病的一种有效治疗方法,已在临床上广泛使用,然而在治疗过程中及治疗完成后患者可能会出现各种原因的疼痛。本文对根管治疗术中疼痛发生的原因进行分析,从而为临床医生采取相应的有效措施和治疗手段缓解患者痛苦提供参考。     

老年人部分闭锁根管的预备

目的:总结对老年人部分闭锁的根管进行根管预备的特点.方法:对50例根管闭锁需进行根管治疗的牙齿,经常规手持器械预备辅助以化学预备——乙二胺四乙酸(EDTA)液,双氧水及氯亚明反复冲洗根管,同时相应增加复诊次数,对根管进行多次预备.结果:50例患牙最终获得满意的根管预备.结论:对于老年人部分闭锁的根管,通过手持器械加化学预备多次根管扩大,可以获得满意的根管预备.     

A primary observation on the preparation and obturation of oval canals

AIM: The aim of this study was to observe the existence and assess the quality of obturation of uninstrumented recesses in oval canals. METHODOLOGY: The balanced force technique was used in two groups of oval canals in human mandibular incisors. The canals in group 1 were enlarged to conventional sizes, whereas canals in group 2 were enlarged more widely. All canals were obturated with cold laterally condensed gutta-percha. Two horizontal sections were cut in the apical portion of each filled root. Images of the cross-sections were scanned and analysed using the KS100 Imaging system. RESULTS: Uninstrumented recesses appeared in 13 (65%) oval canals. The recesses in five of these 13 canals were obturated without visible voids. The recesses in the other eight canals were either obturated with visible voids or completely unfilled. The percentage of filled area was significantly higher in group 1 than in group 2 (P < 0.05). CONCLUSIONS: Uninstrumented recesses may be left in many oval canals after preparation using the balanced force technique and these recesses may often not be completely obturated with cold laterally condensed gutta-percha.     

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C形根管是一种根管形态的变异,主要特征是根管横截面形态呈弧形,好发于黄种人.C形根管的特殊形态给临床治疗如根管疏通、清理和充填带来了挑战,本文将详细介绍C形根管的形态、识别及处理方法.     

Weight loss of endodontic sealers, cements and pastes in water

Abstract – A solubility test based on weight loss in water, as proposed for standard testing programs (ADA & ISO), was adapted for assessing the solubility of 10 root canal sealers, cements and pastes. The weight loss of the set materials during 24 hr in distilled water at 37°C ranged from –0.84 (AH26) to 22.71 (Kloroperka N-Ö) weight percent. The results were reproducible, and the test was considered suitable for routine testing of weight loss in water of endodontic materials. However, the test may not provide information which is directly related to the clinical behavior of the materials.     

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根管预备的生物学目标是尽可能地控制根管系统的感染,然而,由于根管系统的无规律性,如根管间狭长间隙(narrow isthmi)和根尖三角区(apical deltas)等,单纯器械预备不可能彻底清理.     

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。     

下颌第二磨牙C形根管的特点和临床治疗

目的探讨下颌第二磨牙C形根管的发生率、临床诊断和治疗方法。方法通过对152例下颌第二磨牙拍摄术前X线片和术中根管探查,按照Melton标准诊断C形根管;采用机用镍钛器械Hero642进行根管预备,次氯酸钠超声冲洗,热牙胶垂直加压技术充填根管。记录C形根管的发生率及临床特点,根据治疗前、中、后的X线片评价根管预备和充填的效果。结果下颌第二磨牙C形根管的发生率为32.2%,79.6%的C形根管患牙X线片表现为锥形融合牙根,20.4%表现为近、远中独立牙根;所有患牙均无根管内并发症发生,治疗效果好。结论下颌第二磨牙C形根管主要存在于融合牙根,根管探查结合X线片可诊断C形根管;机用镍钛器械预备根管、次氯酸钠超声冲洗和垂直加压技术充填根管可获得良好的治疗效果。     

根管预备并发症及充填质量的临床评价

目的：对根管预备并发症及充填质量进行临床评价。方法：从Digora图像系统中抽取我科2002—04—05所完成的根管治疗病例805例，分别对前牙、前磨牙和磨牙根管预备并发症的发生和充填质量进行分析。结果：形成台阶和侧穿的比例在前磨牙分别为4％，而在磨牙中则分别为33％和5％。前牙、前磨牙和磨牙适充的比例分别为74％、69％和50％。结论：磨牙根管预备和充填的质量仍有待进一步提高。     

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     

197个透明后牙的制备与根管形态的观察

１９７年透明（前磨牙和磨牙）经制备并作根管的形态学观察，结果显示４型根管形态。并以根管形态学的临床意义进行讨论。     

根管治疗工作长度确定之惑及解决之道

牙髓根尖周疾病是一类细菌感染性疾病,疾病晚期细菌常定植于整个根管系统。临床治疗该类疾病的主要方法是根管治疗术,彻底清除根管内感染是该技术的核心,也是取得治疗成功的关键,其中准确的根管工作长度是彻底清除根管内感染的前提和保证。但如何准确地确定根管工作长度,尤其是确定根尖止点的位置一直是牙髓专科医生讨论的热点话题,并常常给许多临床医生造成疑惑。本文就牙齿根尖解剖结构的复杂性、根尖止点确定存在的疑惑以及根管工作长度确定方法作简要介绍。     

Relationship between file size and stiffness of stainless steel instruments

Abstract The purpose of this study was to evaluate the relationship existing between file size and stiffness for three endodontic files of different cross-sections. Three groups of instruments were tested: Flexofiles from the Maillefer company. K Files and K-Flex from the Kerr company. Flexofiles have a triangular cross-section, K Files a square cross-section, and K-Flex instruments a rhombus cross-section from size 15 to size 40. For each group, 10 files from size 15 to size 40 were compared according to ANSI/ADA specification N° 28 for bending moment evaluation. There was a statistical difference between the three groups: the square cross-section K files presented a larger bending moment than the rhombus cross-section K Flex, which presented a higher bending moment than the triangular cross-section Flexofiles. There was an exponential relationship between file size and bending moment.     

上颌第一恒磨牙近中颊根根管宽度和锥度测量分析

目的: 测量分析上颌第一恒磨牙近中颊根根管宽度和锥度,为临床提供参考。方法: 收集50颗上颌第一恒磨牙制作透明牙,然后自近中颊根根尖孔处每隔0.4 mm与根管走行方向垂直连续横切,立体显微镜下放大30倍测量各个切片宽度,计算根尖1/3、中1/3、颈1/3各区段的锥度值。结果: 近中颊根第一根管宽度：根尖最大径（0.38±0.12）mm、最小径（0.34±0.16）mm,根中最大径（0.55±0.26）mm、最小径（0.57±0.12）mm,根颈最大径（1.13±0.34）mm、最小径（0.59±0.18）mm。第二根管宽度：根尖最大径（0.25±0.13）mm、最小径（0.28±0.10）mm,根中最大径（0.36±0.09）mm,最小径（0.17±0.06）mm,根颈最大径（0.79±0.23）mm、最小径（0.23±0.17）mm。近中颊根第一根管锥度：根尖1/3最大径0.03 mm、最小径0.01 mm,中1/3最大径0.06 mm、最小径0.03 mm,冠1/3最大径0.10 mm、最小径0.09 mm。第二根管锥度：根尖1/3最大径0.02、最小径-0.01,中1/3最大径0.06,最小径0.00,冠1/3最大径-0.02、最小径-0.02。结论: MB1具有较大的宽度和锥度,且根尖1/3、中1/3、冠1/3锥度不同,而MB2的宽度和锥度都很小,还会出现倒锥度。     

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。