旋转器械对重度弯曲根管再治疗充填材料清除效果的体外研究

发布时间：2018-06-15 04:15

本文选题：显微CT + 旋转速度　；参考：《山东大学》2017年博士论文

【摘要】：研究背景及研究目的:根管治疗术被认为是牙体牙髓病领域中极为重要的治疗技术,它有效提高了牙齿的保留率和生存时间,最大程度保证了患者的咀嚼效率和生活质量。在临床治疗中,由于种种原因,如根管复杂的解剖形态,患牙冠部的渗漏、根管内残留感染物、根尖周炎症及全身因素的影响,都会导致根管治疗的失败。此时,非外科的根管再治疗术是保留患牙的首选方法。根管再治疗的主要目的是在不损伤软硬组织形态功能的前提下,通过彻底清除根管系统内的坏死组织、细菌以及原有充填材料,保持根管系统的无菌状态,并再次建立通畅的根管通路。影响根管再治疗成功率的原因有很多,其中根管形态的复杂性和根管再治疗方法的差异性是重要因素,它们会导致根管再治疗过程中出现大量的根尖溢出碎屑,这是造成术后炎症反应的主要原因。另外根管再预备不彻底,残留根充材料和坏死组织,导致持续存在根管内的感染也可以造成再治疗的失败。因此,为了有效地解决以上两个主要问题,从而获得良好的再治疗效果,选择具有理想再治疗特性的器械和安全、高效的再治疗方法极为重要。目前,国内外关于根管再治疗的研究很多,在再治疗过程中碎屑产生量的控制、根管原有充填材料的清除效果,以及在治疗过程中对根管原有形态的影响方面是研究的主要方向。在以往的研究中,有多种根管再治疗的方法被采用,如应用手用扩大器械、携热器械、激光、超声器械,以及根管充填材料溶解剂的辅助应用等。这些技术各有优缺点,但不同程度地都会导致根尖部碎屑溢出,且均不能完全去除根充材料,导致根管内残留充填材料及感染物,因而根管再治疗技术的标准化治疗流程、操作规范和质量评定标准至今没有制定。近年来,随着镍钛旋转器械的兴起,在牙体牙髓领域引起了一场革命,它的独特功能和特性提高了根管预备的效果和效率。在应用于根管预备领域取得巨大成功后,镍钛旋转器械又被试用于根管再治疗领域中,产生了一些专用于再治疗的旋转器械,如ProTaper再治疗系统、Self-Adjusting再治疗锉等,其主要依据是利用它们独特的设计、旋转作用和镍钛金属具有的物理特性,提高清除根充材料的能力和效率,在弯曲根管再治疗中减少对根管壁牙本质的过度切削,并减少根尖碎屑的产生和溢出,从而预防治疗期间炎症的发生,保证再治疗疗效,它代表了根管再治疗技术今后的研究方向。此外,以往再治疗实验多涉及直根管,但临床上弯曲根管造成再治疗困难的情况最为常见,主要有两个方面的原因:一,镍钛旋转器械在根尖部会造成严重的根管偏移,进而导致无法在根尖弯曲处彻底清除根充材料。二,操作者在操作中由于根管弯曲度的限制严重影响视野,即使在根管显微镜的辅助下,也无法直视到根管每一区域。因此根管过高的弯曲程度提升了再预备的操作难度,增加了操作过程中根尖碎屑的产生量。本研究采用重度弯曲根管作为研究样本,为今后临床上根管再治疗技术的实际应用提供理论指导和参考依据。由于以往镍钛旋转器械由于受到自身物理特性和加工工艺的限制,使的有利于提高再治疗效果的某些性能不能得到充分体现,如器械旋转速度、弹性等,也影响了再治疗技术的发展。本研究根据以往研究经验,选用新型的根管预备系统Twisted Files(TF;卡瓦盛邦,美国)作为根管再预备的主要器械。它具有特殊的器械设计理念,拥有良好的弯曲特性,抗循环疲劳的能力,以及特殊的尖端设计和工作螺纹,有利于顺利进入弯曲根管,预备效果良好,能最大限度地顺应根管的原有形态,避免产生台阶、穿孔和根管偏移等现象,在复杂根管预备中表现出了优于其它预备器械的特点,另外作为高速旋转器械,它的工作速度远远高于其他品牌产品,预期可以提高根管再预备的工作效率,较高旋转速度产生的热量可能会促进根充材料的有效清除,并减少根尖碎屑的产生量,具备根管再治疗器械所应该具有的特质。关于TF在根管再治疗过程中根管充填材料清除效果的的研究,至今罕有报道。本研究的目的是通过对其根管再治疗特性的体外研究,评价根管镍钛旋转器械在不同旋转速度下对弯曲根管进行再治疗充填材料的清除效果,并计算溢出根尖孔的碎屑质量,以及根管内残余充填材料的比例,同时记录操作时间,初步评估其再治疗的性能,为提高根管再治疗清除效果提供理论依据和数据支持,从而确立未来根管再治疗技术的研究方向。材料与方法:选用因为牙周病而拔除的具有弯曲近颊侧根管的离体下颌第一磨牙48颗作为实验牙齿。要求牙体形态完整、牙根发育完成仅有单一根管孔,未进行过牙体牙髓治疗。用Schneider法以及Schafer法,对下颌第一磨牙近中颊根根管弯曲程度进行评估,弯曲角度用α表示,弯曲半径用r表示。选用25° ≤ α ≤35°,r≤10mm的根管作为实验对象。应用10号K型扩大锉通畅根管至根尖,清除牙面上附着的软组织、牙石和色素,并储备在0.09%的生理盐水中。应用ProTaper机用镍钛锉以冠向下预备法,对样本根管进行初次预备后,选用热牙胶连续波充填技术完善充填根管,冠部封闭后置于37℃水浴中2周备用。并将样本随机分为四组,应用TF机用镍钛锉以500rpm、1000rpm、1500 rpm的旋转速度,分别对A、B、C组进行二次预备,去除根管充填材料。应用手动器械对D组进行二次预备。用预先称重的离心管收集溢出根尖孔的碎屑,比较并计算再治疗前后离心管的质量差,得出碎屑量。另外采用显微CT技术,对二次预备前后的样本进行扫描,评估各组根管内各部分残留根管充填材料的百分比例,同时比较各组工作时间。应用单因素方差分析法对各组实验结果进行统计学分析。结果:1.根尖溢出碎屑本实验中所有再治疗技术均能产生根尖碎屑,手工器械组(D组)产生的碎屑量(0.69±0.04mg)明显多于其他应用旋转器械各组(A:0.54±0.05mg;B:0.48±0.04 mg;C:0.42±0.03 mg;all P0.001)。C组产生的溢出碎屑量最少,与其他各组碎屑量有显著差异。镍钛器械旋转速度越快,溢出的碎屑量也就越少。A、B、C三组之间的数据差异有统计学意义(Avs.B:P=0.006;Bvs.C:P0.001;A vs.C:P0.001)。2.根管残余充填材料结果显示,本实验中所有应用的再治疗技术均不能完全清除根充材料。剩余材料比例在4%-8%之间。与其它各组相比,C组剩余的残余充填材料比例(4.01±0.68)明显少于其各组(A:5.78±0.93;B:5.28±0.53;D:5.03±0.60;all P0.01),有显著差异,尤其在根尖5mm处尤为明显(A:7.72±0.76;B:6.95±0.78;C:6.04±0.79;D:6.90±0.75;all P0.01)。手动器械组与A、B组剩余充填材料比例之间无统计学意义。3.工作时间各分组再治疗器械首次到达工作长度所耗时间(T1)相比:C组所耗时间最少,各分组之间的数据差别有统计学意义(Avs.B:P0.001;B vs.C:P0.001;A vs.C:P0.001;A vs.D:P=0.036).各分组完成根管再预备所耗时间(T2)相比:手工器械组(D组)操作时间(19.70±0.30)明显多于其他应用旋转器械各组(A:8.08±0.23min;B:5.80±0.26min;C:3.53±0.33min)。4组间均有统计学差异(P0.01)。结论:本研究对减少根尖溢出碎屑的产生,以及如何提高根管再治疗清除效果提供了重要的参考依据,并得出以下结论:1.第一部分实验中,各组均有根尖碎屑溢出,TF的旋转速度越快,根尖产生碎屑越少,较高的旋转速度与低速以及手动器械相比,可以显著减少根尖碎屑的产生,旋转速度与碎屑产生量呈正相关关系。2.在第二部分实验中,所有分组均留有残余充填材料,TF旋转速度1500rpm时,残余的根管充填材料比例最少,其余各组残余材料比例之间无显著性差异。在重度弯曲根管中,当旋转速度达到一定要求时,较高的旋转速度与低速以及手动器械相比,可以带来更佳的再治疗效果。在较低旋转速度l000rmp以下时,尚不能达到预期的清除效果。3.TF的旋转速度越快,所需要的再治疗的操作时间越少。在1500rpm时,所用的操作时间最少。综上所述,镍钛器械的旋转速度有可能成为影响根管再治疗效果的重要因素。在一定的速度范围内,同一旋转速度对根尖碎屑的产生和残余根充材料比例的影响程度并不完全一致。在今后,我们还需要进一步改进离体实验设计,尽可能模拟体内环境,对器械的旋转速度以及影响根管再治疗疗效的各种因素作进一步的深入评估,找出最适宜的工作速度和工作方式,在减少根尖碎屑产生和减少残余充填材料,以及提高工作效率等方面同时达到理想效果,建立根管再治疗的标准化操作流程。
[Abstract]:Research background and purpose: root canal therapy is considered as a very important treatment in the field of dental pulp disease. It effectively improves the retention and survival time of the teeth, maximally guarantees the chewing efficiency and quality of life of the patients. In clinical treatment, because of the species, such as the complex anatomical shape of the root canal, the crown part Leakage, residual infection in the root canal, periapical inflammation and systemic factors will lead to the failure of root canal therapy. At this time, non surgical root canal retherapy is the first choice to retain the affected teeth. The main purpose of root canal retherapy is to eliminate the damage in the root canal system without damaging the shape and function of the soft and hard tissue. Dead tissue, bacteria and original filling materials keep the aseptic state of the root canal system and reestablish a smooth root canal pathway. There are many reasons for the success rate of root canal retreatment, in which the complexity of root canal morphology and the difference in root canal retreatment are important factors, which can lead to a large number of root canal retreatment processes. The root tip spilt debris, which is the main cause of the postoperative inflammatory response. Besides, the root canal is not prepared thoroughly, the residual root filling material and necrotic tissue can lead to the persistent infection in the root canal, which can also cause the failure of retreatment. Therefore, in order to effectively solve the above two major problems, a good retreatment effect can be obtained. At present, there are many studies on root canal retreatment at home and abroad, the control of the amount of debris in the process of retreatment, the removal of the original filling material of the root canal, and the effect of the original shape of the root canal in the treatment process is the main research. Direction. In previous studies, a variety of root canal retreatment methods have been used, such as the use of hand expanded instruments, heat carrying instruments, lasers, ultrasonic instruments, and the auxiliary applications of root canal filling materials. These techniques have advantages and disadvantages, but can lead to the spillover of the root apex to varying degrees, and can not completely remove the root charge material. The standard treatment process of root canal retreatment, operation specification and quality assessment standards have not been formulated so far. In recent years, with the rise of nickel and titanium rotating instruments, a revolution has been made in the field of dental pulp. Its unique functions and characteristics have improved the effect of root canal preparation. After a great success in the field of root canal preparation, the nickel titanium rotary instrument has been tried in the field of root canal retreatment and produced some revolving instruments for retreatment, such as the ProTaper retreatment system, and the Self-Adjusting retreatment file, which is based on their unique design, rotation and nickel and titanium metal. It has the physical characteristics to improve the ability and efficiency of scavenging root filling material. It reduces the overcutting of root canal dentin in the retreatment of root canal, reduces the production and spillover of the root canal, thus preventing the occurrence of inflammation during the treatment, and ensures the retreatment effect. It also presents the future research direction of root canal retreatment technology. Besides, Most of the previous retreatment experiments involve the direct root canal, but the clinical flexural root canal is the most common cause of retreatment. There are two main reasons: first, the nickel titanium rotating apparatus causes serious root canal migration in the root tip, which leads to the inability to completely remove the root charge material at the root tip bending. Two, operator in operation because of root canal. The limit of curvature of the tube seriously affects the field of vision, even with the aid of the root canal microscope, which can not be directly seen in each region of the root canal. Therefore, the degree of excessive bending of the root canal increases the difficulty of the operation of the re preparation, and increases the production of the crumbs in the operation. Because of the limitations of the physical properties and processing techniques of the nickel titanium rotating instruments, some of the properties that are conducive to the improvement of the retreatment effect can not be fully reflected, such as the speed of rotation and the elasticity of the apparatus, which also affects the development of the retreatment technology. According to previous research experience, this study selects the new root canal preparation system Twisted Files (TF; kava state, United States) as the main equipment for the root canal preparation. It has a special device design concept, with good bending characteristics, anti cyclic fatigue ability, and special cutting-edge design and working thread, which is beneficial to the smooth entry. The curved root canal has good preparation effect. It can conform to the original shape of the root canal to the maximum extent, avoid the phenomena of step, perforation and root canal migration. In the preparation of complex root canal, it is superior to other preparatory instruments. In addition, as a high-speed rotary instrument, its working speed is far higher than that of other brand products, and it is expected to increase the root of the root canal. The efficiency of the repreparation of the tube, the heat generated by the higher rotation speed may promote the effective clearance of the root filling material, and reduce the amount of the root tip fragments, and have the characteristics that the root canal retreated instruments should have. A rare report on the effect of root canal filling material on the retreatment of root canal in TF has been rare. The purpose of this study is to evaluate the effect of the root canal retreatment in vitro, to evaluate the removal effect of the retreated root canal filling materials for the root canal nickel titanium rotating apparatus at different rotational speeds, and to calculate the debris quality of the spillover root tip and the ratio of the residual filling materials in the root canal, and to record the operation time and evaluate the retreatment of the retreatment. The performance of the therapy provides a theoretical basis and data support for the enhancement of root canal retreatment, thus establishing the future research direction of the root canal retreatment technology. Materials and methods: 48 of the first molar of the mandibular first molar extracted with the curved lateral buccal lateral root canal because of periodontitis are used as the experimental teeth. The shape of the tooth is required to be complete, Ya Genfa The bending degree of the proximal and middle buccal root canal in the first molar of the mandible was evaluated by Schneider and Schafer. The bending angle was expressed by R and the bending radius was expressed by R. The root canal of 25 = < < < < 35 degrees and R < 10mm was selected as the experimental object. The application of the 10 K type expansion file was unobstructed. The root canal to the root tip, remove the soft tissue, stone and pigment attached to the tooth surface, and reserve it in 0.09% of the normal saline. The ProTaper machine is used with a nickel titanium file to prepare the crown down method. After the initial preparation of the sample root canal, the hot tooth glue continuous wave filling technique is used to fill the root canal and the crown is closed in 37 centigrade water bath for 2 weeks. The samples were randomly divided into four groups. The rotating speed of 500rpm, 1000rpm, and 1500 rpm was used by TF Ni Ti file to prepare two times for A, B, C group, and the root canal filling material was removed. The manual instruments were used to prepare the D group for two times. The fragments of the spillover root holes were collected with the pre weighing centrifuge tube, and the quality of the centrifuge tube before and after retreatment was compared and calculated. In addition, the amount of debris was obtained. In addition, micro CT was used to scan the samples before and after two preparation, to evaluate the percentage of the residual root canal filling materials in each part of root canal, and to compare the working time of each group. The results of each group were statistically analyzed by single factor analysis of variance. Results: 1. root spillover fragments. All the retreatment techniques in the experiment could produce root apex fragments. The amount of debris (0.69 + 0.04mg) produced by the manual apparatus group (group D) was significantly more than that of other rotating instruments (A:0.54 + 0.05mg; B:0.48 + 0.04 mg; C:0.42 + 0.03 mg; all P0.001). The amount of spillover fragments produced by the.C group was the least. The faster the rotation speed, the less the amount of spillover fragments is.A, B, C three groups of data differences between the three groups are statistically significant (Avs.B:P=0.006; Bvs.C:P0.001; A vs.C:P0.001).2. root canal residual filling material results show that all the application of retreatment technology can not completely remove the root charge material. The proportion of residual material is between 4%-8%. The residual filling material ratio (4.01 + 0.68) of the C group was significantly less than that of each group (A:5.78 0.93; B:5.28 + 0.53; D:5.03 + 0.60; all P0.01), especially in the root tip 5mm (A:7.72 + 0.76; B:6.95 + 0.78; C:6.04 + 0.79; D:6.90). There was no statistical significance between the.3. working hours and the time (T1) for the first time to reach the work length (T1): the C group took the least time, and the data difference between the groups was statistically significant (Avs.B:P0.001; B vs.C:P0.001; A vs.C:P0.001; A vs.D:P=0.036). The operation time of the apparatus group (group D) (19.70 + 0.30) was significantly more than that of other rotating instruments (A:8.08 + 0.23min; B:5.80 + 0.26min; C:3.53 + 0.33min).4 group had statistical difference (P0.01). Conclusion: This study provides an important reference for reducing the production of root tip spillovers and the removal of the high root canal, as well as the removal of the high root canal. The following conclusions are drawn: 1. in the first part of the experiment, each group has spillover of root apex, the faster the rotation speed of TF, the less the crumbs produced in the root tip, the higher rotation speed and the low speed and the manual apparatus, which can significantly reduce the production of the root tip fragments, and the rotation speed is positively related to the amount of debris production in the second part of the experiment. All the groups have residual filling materials. When the rotation speed of TF is 1500rpm, the residual root canal filling material has the least proportion, and there is no significant difference between the remaining materials. In the severe curved root canal, when the rotation speed reaches a certain requirement, the higher rotation speed is better than the low speed and the manual equipment. Retreatment effect. At a lower rotational speed of l000rmp, the faster the rotation speed of.3.TF is not reached, the less operation time required. At 1500rpm, the operation time is the least. In summary, the rotation speed of the nickel titanium instrument may be an important factor affecting the effect of root canal retreatment. In a certain range of speed, the same rotation speed does not fully agree with the effect of the generation of the apical debris and the proportion of the residual root charge material. In the future, we need to further improve the experiment design in vitro, simulate the internal environment as much as possible, the speed of the apparatus and the various factors that affect the curative effect of the root canal retreatment. In order to find the most suitable working speed and mode of work in one step, we can achieve the ideal effect in reducing the production of the root tip debris and reducing the residual filling material and improving the working efficiency, and establish the standardized operation process of the root canal retreatment.
【学位授予单位】：山东大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：R781.05

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