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。     

根管冠部预处理对前磨牙弯曲根管预备效果的影响

目的:研究根管冠部预处理对预备弯曲前磨牙根管时根尖偏移的影响。方法:将60个15°～35°的弯曲前磨牙根管按弯曲度排序后分成15个区组,每区组4个根管,再随机分配至4个不同处理组。其中2组根管冠部用GG钻预处理后,分别用不锈钢和镍钛合金K锉行常规法预备根管;另2个对照组直接行常规法根管预备;记录各组根管预备至不同锉号时的根管影像及器械尖端所在位置。最后,测量比较根管预备前后弯曲度的变化和不同锉根管预备后的根尖偏移指数(ATI)。采用t检验或配对资料的符号秩和检验进行统计学处理。结果:各组根管预备前后的弯曲度之间均有显著差异(P<0.01),ATI均随锉号的增大而增大。用不锈钢锉预备根管,经过冠部预处理,根管侧穿数目明显少于对照组,且30#锉所致的根尖偏移显著低于对照组(P<0.01),与同型镍钛合金K锉所产生的根尖偏移无差异(P>0.05)。结论:对于前磨牙弯曲根管,用镍钛合金锉预备,其效果优于不锈钢锉;不论是镍钛合金K锉还是不锈钢K锉,在用常规法预备弯曲前磨牙根管时,均应进行根管冠部预处理。     

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。     

RootZX根管测量仪与X线片测量根管长度的比较研究

目的比较RootZX型根管长度测量仪与X线片定位法对根管长度测量的准确性。方法选取门诊需根管治疗的病例107颗患牙，根管总数213个，采用G钻预备根管口，RootZX根管氏度测量仪初测根管长度后，插K锉以标准投照技术拍摄X线片，测量诊断丝距根尖的距离用以评价RootZX测量的准确性。结果RootZX根管长度测量仪与X线片测量根管长度无显著差异（P〉0．05），误差在±0．5mm内的根管数有207个，准确率达97．18％。结论RootZX根管长度测量仪可用于临床，是一种准确性较高，重复性较好，能减少X线损害的根管治疗定位仪器。     

Propex根管测量仪临床应用操作分析

目的:探讨Propex根管测量仪临床操作中的具体细节,为更好的临床实践提供依据.方法:选取重度牙周炎需拔除的前牙150颗,分为三组:A组:牙髓活力正常者84例;B1组:牙髓无活力根尖周组织正常者37例;B2组:牙髓无活力根尖周组织有破坏者29例.以Propex根管测量仪和15号手用不锈钢K型锉测量工作长度,带锉拍摄X线片,拔牙后,观测锉尖端在根尖区位置.结果:锉尖端至解剖性根尖孔距离在A组与B1组两组间差别无统计学意义(P>0.05),两组在距解剖性根尖孔0.5mm-1mm;锉尖端至解剖性根尖孔距离A组与B2组以及B1组与B2组间差别均差异具有统计学意义(P<0.01),B2组即牙髓坏死合并根尖周组织有破坏时,距解剖性根尖孔大部分P<0.5mm,甚至穿出解剖性根尖孔.结论:Propex可准确定位生理性根尖孔,牙髓有无活力对定位无影响,但根尖周破坏时准确性降低.     

上颌第二恒磨牙近中颊根第二根管的离体牙研究

目的研究上颌第二恒磨牙近中颊根第二根管（MB2）的发生情况,为提高上颌第二恒磨牙根管治疗的成功率提供解剖学基础。方法于山东地区收集离体上颌第二恒磨牙118颗,采用斜方型开髓洞型开髓,利用小号C型锉探查并疏通根管,记录MB2的发现率及扩通率;拍摄X线牙片,记录近中颊根的根管数目、形态和类型;在根管显微镜下观察并应用数显卡尺测量近中颊根主根管和MB2根管口之间的距离,确定根管口的位置;记录近中颊根的根尖孔数目,并测量解剖根尖孔至解剖根尖的距离。结果118颗上颌第二恒磨牙中,有58颗发现MB2,发现率为49.15%;其中48颗牙齿的MB2被扩通,扩通率为82.76%。108颗3根牙中,近中颊根的根管形态为Ⅰ型者有50颗,占46.30%;Ⅱ型及Ⅲ型者分别为14和34颗,占12.96%和31.48%。近中颊根主根管口与MB2根管口的平均距离为1.26 mm;近中颊根解剖根尖孔至解剖根尖的距离平均值为1.13 mm。结论山东地区上颌第二恒磨牙MB2的发现率较高,临床治疗中采用改良的斜方型开髓孔有利于发现MB2,用X线片确定工作长度时需要结合临床综合判断根尖孔的位置。     

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目的    研究根管冠部预处理对预备磨牙弯曲根管根尖偏移的影响。方法    从2006—2008年就诊于沈阳市口腔医院颌面外科121例患者因牙周病拔除的135颗磨牙中选取72个12  ~ 35°的弯曲磨牙根管，按照Schneider测量根管弯曲方法分成中度弯曲组（12  ~ 20°）和重度弯曲组（21 ~ 35°），每组36个根管，各组再按随机原则分为试验组和对照组，各18个根管。试验组：根管冠部用GG钻预处理，常规用10 ~ 35号不锈钢K锉进行根管预备；对照组：直接行常规法根管预备。记录各组根管预备至不同锉号时的根管影像，测量并比较各组不同锉号预备后的根尖偏移指数（ATI）。结果    中度弯曲组和重度弯曲组中，经冠部预处理的试验组ATI均明显小于对照组，差异有统计学意义（P < 0.05）；随锉号的不断增大，根尖偏移指数也逐渐增大，且试验组根管侧穿数明显小于对照组。结论    磨牙弯曲根管预备时经冠部预处理的根管预备效果优于常规处理。     

ProPex测量仪对磨牙根管工作长度准确性的临床评价

目的:评价ProPex根管测量仪测量磨牙根管工作长度的准确性.方法:选择50例根尖周病患者,共102个磨牙.患牙随机分为两组,实验组采用ProPex根管测量仪测量根管工作长度,对照组采用X线法计算根管工作长度,常规根管预备充填,摄X线牙片了解其准确性.结果:实验组根管充填适充率显著高于对照组(p＜0.05).结论:ProPex根管测量仪方便、快捷,能够准确测量根管长度.     

根管治疗的临床体会

根管治疗早已广泛应用于牙髓病及根尖周病的治疗中,但实际上能否恰填而取得成功则取决于临床治疗中对根管工作长度的准确测量,而目前的测量方法如手感法与X线片测量方法等,因个体差导致其效果不同。现将20例牙髓病或根尖周病的患者在治疗中出现不同结果总结如下。 资料与方法 1.病例 20例牙髓病或根尖周病患者,共32颗牙进行治疗,其中多根管牙28颗,单根管牙4颗。年龄16～70岁。 2.方法 对患牙常规开髓,揭去髓室顶,找到根管口,先用指感法测量根管长度,暂不摄X线片。用15~#扩大针插入根管至患者感到疼痛时即停,以此感觉为达到根尖孔及指标,即刻进行X线片拍照,观察X线片上的扩大针是否达到根尖孔。然后进行根管预备、充填。     

根管充填压器对垂直根管充填封闭性能的影响

材料和方法 选用90颗发育完全的单根管前牙,截冠,在根管中插入10~#锉至根尖孔处刚可看到并减去0.5mm来确定工作长度,用K型锉常规清理和成形根管,再用15~#～60~#扩孔钻和1~#～4~#Gates Glidden钻完成根管扩大,并用10~#锉及反复插入根管以保证根尖孔开放,所有根尖区都预备至30~#锉。牙齿任意等     

A comparison between in vivo radiographic working length determination and measurement after extraction

The purpose of this study was to compare the difference between the in vivo working length established by viewing a periapical radiograph and the in vitro measurement from the file tip to the apical foramen of the extracted tooth. Twenty-six canals from teeth that had been treatment planned for extraction were accessed under rubber dam isolation. The coronal portion of each canal was flared using Gates Glidden drills, and a K-type file was inserted down the canal until an electronic apex locator indicated that the file had reached the apex. A size 20 K-type file was locked into place with glass ionomer cement at this position. A radiograph was exposed and the tooth was extracted. Each tooth was viewed using a videomicroscope at 30x original magnification, and the distance from the file tip to the most coronal aspect of the major foramen was measured. Six examiners viewed each radiograph and assessed the working length of each canal. Chi(2) analysis of the data revealed a significant difference (p < 0.01) between the estimation of working lengths and the microscopic measurements. The examiners overestimated the distance between the file tip and the apical foramen of the tooth when the file was placed short, and underestimated the distance when the file was placed long. In conclusion, when the file is short it is actually closer to the apical foramen than it appears radiographically; when it is long it is actually longer than it appears radiographically.     

Evaluation of the incidence of transportation after placement and removal of calcium hydroxide

The purpose of this in vitro study was to evaluate the incidence of apical transportation after the placement and removal of Ca(OH)2 in straight and curved root canals. Twenty maxillary central incisors (group A) and 20 mesiobuccal canals from mandibular molars (group B) were instrumented at the working length to a #45 file and #30 file, respectively. Postinstrumentation radiographs were taken with the corresponding final file inserted into the canal to the working length. Afterward, the root canals were filled with a Ca(OH)2 paste using Lentulo spirals, and the teeth incubated for 7 days. The Ca(OH)2 paste was then removed up to the working length using a #45 file for group A and a precurved #30 file for group B. Final radiographs were taken with the file inserted into the canal to the working length. Postinstrumentation and final radiographs were superimposed to evaluate the incidence of transportation. As expected, in group A (straight canals) no transportation was detected, whereas in group B (curved canals) 9 of 20 canals showed apical transportation (95% confidence interval, 23.1-68.5% transportation). Statistically significant differences were observed between groups A and B (p < 0.05).     

An in vitro evaluation of the accuracy of Dentaport ZX apex locator in enlarged root canals

BACKGROUND: The aim of this study was to examine the effects of root canal irrigants on the accuracy of Dentaport ZX electronic apex locator (EAL) in enlarged root canals. Our previous study revealed that as the diameter of the root canal increased, the electronically measured length with small size files became shorter in the presence of blood. It is not known whether different canal irrigants would interfere with the reading accuracy of an EAL in enlarged root canals. METHODS: A total of 45 extracted single-rooted human teeth were used. In Stage 1, canals were instrumented using #10-40 K-files with a #40 K-file as the master apical file (MAF). The teeth were randomly divided into five groups and mounted in an experimental apparatus. The following irrigants were used during electronic canal measurements: Group A = 0.5% NaOCl; Group B = 2.5% NaOCl; Group C = 15% EDTA; Group D = 0.8% chlorhexidine (CHX); and Group E = RC Prep. In Stage 2, the canals were enlarged using a #60 K-file as the MAF. In Stages 1 and 2, the apical portion of the canals was instrumented using the step-back sequence (up to a #80 K-file). In Stage 3, the canals were enlarged again using a #80 K-file as the MAF. In each stage, the canal length was measured with a Dentaport ZX using #10 and #40, #10 and #60, and #10 and #80 K-files for Stages 1, 2 and 3, respectively. Data were analysed by two-way ANOVA and Fisher's PLSD test. RESULTS: Statistical analysis showed significant differences among all groups (p < 0.01). There was no significant difference between Group A and B at each stage and between Group D and E at Stage 2. A statistical significant difference was observed between #10 K-file and other files (#40, #60 and #80) at each stage (p < 0.01). In Groups A and B, there was no significant difference between #10 and #40 K-files (Stage 1) and between #10 and #60 K-files (Stage 2). CONCLUSION: The Dentaport ZX was accurate and not adversely affected by the presence of 0.5% or 2.5% NaOCl and EDTA in the enlarged canals, and the measured lengths obtained with small and large size files were comparable. However, it was accurate in the presence of CHX and RC Prep only when large size files were used, and the length measured with small size files was greater than the actual length.     

The quality of apical canal preparation using hand and rotary instruments with specific criteria for enlargement based on initial apical file size

The aim of this study was to compare the quality of apical enlargement of mesiobuccal canals of mandibular molars using conventional stainless steel hand files (K files) and nickel-titanium (Ni-Ti) rotary instruments (LightSpeed). Thirty freshly extracted mandibular molars were randomly assigned to three equal groups (n = 10 each group). The mesiobuccal canals were instrumented with K file using step-back technique without coronal flaring (control; group 1), K file using step-back technique after coronal flaring (group 2), and LightSpeed instrumentation (group 3). Specific criteria for apical enlargement based on initial apical size were used. For step-back techniques, the master apical file sizes were based on the Grossman criterion of three sizes larger than the first file that bound at working length, without coronal flaring (group 1) and with flaring (group 2). For the LightSpeed (LS) group, the master apical rotary sizes were based on the manufacturer's recommendation. Canal cleanliness, canal transportation, and final canal shapes were determined histologically at 1-mm and 3-mm levels short of the working length. Canals were prepared to significantly larger sizes using LS instrumentation than with either hand instrumentation techniques (15-17 ISO units, p < 0.001). LS instrumentation allowed greater apical enlargement with significantly cleaner canals, less apical transportation, and better canal shape than both hand instrumentation groups at both levels (p < 0.05). None of the three techniques was totally effective in cleaning the apical canal space. It was concluded that greater apical enlargement using LS rotary instruments is beneficial as an attempt to further debride the apical third region in mesiobuccal canals of mandibular molars. Instrument designs, alloy properties, and canal curvature are important factors that determine the feasibility of greater apical enlargement in narrow canals.     

Anatomic Analysis of Palatal Roots of Maxillary Molars Using Micro–computed Tomography

IntroductionThe morphology of the palatal root of maxillary first and second molars was analyzed and compared using micro–computed tomographic scanning.MethodsForty-seven extracted maxillary molars were scanned with a micro–computed tomographic device to analyze the palatal radicular dentin dimensions, canal working width, root length, canal curvature, lateral canals, and apical constriction anatomy. Quantitative data were analyzed with mean and standard deviation for first and second molars, respectively. Comparison was made between first and second molars using an unpaired t test.ResultsThe palatal root of maxillary first molars was found to have statistically significantly thinner dentin than second molars on the palatal aspect of the root 8–11 mm from the apex, correlating to the coronal and middle thirds of the root. First molar palatal roots also had a statistically significantly wider canal mesiodistally than second molars at 13–15 mm from the apex, correlating approximately to the level of the cementoenamel junction and pulpal floor. Significant canal curvature was present. These findings suggest the need for conservative coronal flaring and instrumentation.ConclusionsThe absence of an apical constriction in 76.6% of the specimens highlights the importance of creating an apical seat through instrumentation to maintain obturation materials. A minimum master apical file size of 40 is recommended based on preoperative working widths in the apical 0.5–1.0 mm. A root-end resection of 3.5 mm would remove a greater majority of lateral canals.     

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.     

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.     

两种根管镍钛锉对L形和S形根管成形能力的研究

目的 评价两种机用镍钛锉对弯曲根管的预备成形能力.方法 20个L形树脂根管,随机分为2组,每组10个,分别使用#25,0.04锥度的M3铂金版、S3预备根管,术前术后拍摄数码照片,绘制根管外形线及中心线,分析根管预备前、后工作长度和弯曲角度变化值及根管中心线偏移量.另20个S形树脂根管,分组方法 和实验方法 同L形根管...     

An in vivo comparison of two frequency-based electronic apex locators

The purpose of this study was to compare the accuracy of a two-frequency (Root ZX) and a five-frequency (Endo Analyzer Model 8005) electronic apex locator under clinical conditions. Thirty-two teeth planned for extraction were used. The coronal portion of each canal was flared using Gates Glidden drills and Orifice Shapers. The canals were irrigated with 2.6% sodium hypochlorite. A K-type file was used to determine a separate working length in each canal using the electronic apex locators. The teeth were extracted and the apical 4 mm of each root canal was exposed along the long axis of the tooth. Photographic slides of each canal were projected and the file position in relation to the minor diameter was determined by two investigators. The mean distance between the electronic apex locator working length and minor diameter was 1.03 mm for the Endo Analyzer and 0.19 mm for the Root ZX. A paired sample t test showed that the Endo Analyzer had significantly longer readings beyond the minor diameter than the Root ZX (p < 0.0001). The ability to locate the minor diameter (+/- 0.5 mm) was 90.7% for the Root ZX and 34.4% for the Endo Analyzer Model 8005.