第一恒磨牙根尖孔解剖及其与初锉的关系

目的探讨上、下颌第一恒磨牙根尖孔的解剖及其与初锉尖端的适合性。方法上、下颌离体第一恒磨牙各30颗,冠方预展后确定初锉号数,立体显微镜下观察根尖孔的数目、根尖表面主根尖孔的位置和形态,测量主根尖孔和距根尖孔1mm、2mm、3mm处根管横断面的最大径及最小径。结果78.1%的根管有一个根尖孔;主根尖孔54.8%位于根尖顶,呈椭圆形者占92.5%;主根尖孔和距根尖孔1mm处管径相当,距根尖孔1mm、2mm、3mm处根管的最大径和最小径依次递增;初锉尖端直径比距根尖孔1mm处根管最小径稍小,比最大径平均小三个锉号。结论以根尖狭窄部最小径确定的初锉为基线进行根管机械预备,根管壁的清创质量可能受到影响。     

根尖狭窄破坏对Propex Ⅱ电子根尖定位仪准确性的影响

目的:研究在根尖狭窄破坏的情况下,PropexⅡ测量准确性与根尖孔大小的相关性.方法:磨除40颗单直根管离体牙根尖l mm,采用2％液态琼脂凝胶注入卡斯特罗模型,使用PropexⅡ电子根尖定位仪进行根管长度测量,记录测量值(LP),计算实际测量的根管工作长度(L)与电测法测量的根管工作长度(LP)的差值(△L).显微镜下拍摄根尖孔图像,利用Photoshop CS 6.0软件测量根尖孔面积(S).采用SPSS 22.0软件包对测量结果进行直线相关回归分析.结果:以±0.5 mm作为△L的允许范围,△L均为正值.在根尖狭窄破坏的情况下,PropexⅡ的测量准确率为52.5％.R值为0.903,S与△L呈线性相关.建立的线性回归方程为:S=0.04+0.11×△L.结论:在根尖狭窄破坏的情况下,电子根尖定位仪准确性下降;根尖孔面积越大,准确性越差.     

根尖定位仪测量根尖破坏牙根管长度的准确性研究

目的 比较Root ZX,Propex,Justy Ⅱ和 Raypex5 4种根尖定位仪测量根尖受破坏牙齿工作长度的准确性.方法 将53颗离体牙沿釉牙骨质界截冠、去髓,根管预备到25#,使用Root ZX(A组),Propex(B组),Justy Ⅱ(C组)和 Raypex5(D组) 4种根尖定位仪分别测量每个根管的工作长度;再使用超声倒预备工作尖将以上各牙沿根尖孔破坏根尖狭窄部,再次用4种根尖定位仪测量工作长度.结果 所得数据与解剖镜下测量的实际数据进行比较,根尖完整时A、B、C、D4组数据在-0.5～0.5 mm误差范围内的百分数分别为86.3%、88.8%、85.0%、88.8%.根尖破坏时A、B、C、D4组数据在-0.5～0.5 mm误差范围内的百分数分别为16.7%、20.5%、10.3%、48.7%,在-1～1 mm误差范围内的百分数分别为74.4%、52.6%、57.7%、91.0%.结论 4种根尖定位仪对于根尖破坏的牙齿测量准确性比根尖完整的牙齿要低,相比之下Raypex5的准确性比较高.     

不同镍钛旋转器械平解剖性根尖孔长度预备根管后根尖孔表面形态变化的研究

目的:研究不同镍钛旋转器械在平解剖性根尖孔长度时预备根管后根尖孔表面形态的变化。方法:选取因牙周病拔除的离体牙40颗,随机分为两组并在扫描电子显微镜下拍摄术前片,记录根尖孔表面形态;分别采用K3锉、TF锉在工作长度下(平解剖性根尖孔长度)预备根管,扫描电子显微镜下观察并记录预备后根尖孔表面形态的变化:记录根尖孔的偏移、根尖孔周围牙骨质缺损及根尖孔周围表面的裂纹。结果:K3组、TF组根管预备后均存在根尖孔的偏移、牙骨质的缺损及根尖孔周围表面的裂纹,其中根尖孔的偏移的样本数目、根尖孔周围牙骨质缺损样本数目两组之间存在统计学差异(P<0.05),根尖孔周围表面裂纹样本数两组之间无统计学差异。结论:K3、TF两种镍钛旋转器械在平解剖性根尖孔长度下预备根管时由于超根尖止点预备,均可导致根尖孔偏移,根尖孔周围的牙骨质缺损及根尖孔表面裂纹线产生,与K3锉相比,TF锉在减少根尖孔偏移及根尖孔周围牙骨质缺损方面更具优越性。     

根尖孔大小对牙髓组织再生及牙齿抗压强度的影响

目的:探讨根尖孔大小对牙髓组织再生及牙齿抗压强度的影响。方法:收集因正畸拔除的牙根发育完成、 无牙根折裂的单根下前磨牙,离体牙截冠后,保留12 mm牙根,随机分为5组,每组25颗牙,根管预备至不同主锉号数,分别为30#、40#、60#、80#及100#主锉组,其中30#主锉组为对照组。体外培养人牙髓干细胞并接种于0.25%水凝胶支架中,将其分别注入不同主锉预备过的根管内,每组均取5颗牙,其牙根于Transwell小室分别培养14、21、28 d,提取水凝胶中细胞的总RNA,进行实时定量聚合酶链反应(real-time polymerase chain reaction,Real-time PCR)检测;每组余下的10颗牙,其牙根冠部封闭后植入裸鼠皮下,28 d后取出,5颗进行组织学观察,5颗进行静态载荷实验。结果:Real-time PCR检测牙本质涎磷蛋白(dentin sialophosphoprotein, dspp)、牙本质基质蛋白-1(dentin matrix protein-1, dmp-1)的表达,第28天时,各实验组均高于对照组(P<0.05),且40#主锉组高于其它实验组(P<0.05)。组织学分析表明,30#、40#、60#主锉组均未见连续的牙髓样组织形成,80#、100#主锉组可见组织形成,但未表现出典型牙髓样组织结构。静态载荷实验结果表明,40#主锉组的平均抗压载荷与对照组比较差异无统计学意义,其它实验组均低于对照组(P<0.05)。结论:根尖孔预备至100#(1 mm)以内时,根尖孔大小对牙髓组织再生没有明显影响,但根尖孔预备大于40#时,抗压强度明显下降。     

手用不锈钢K锉和机用Profile镍钛锉在根管预备中碎屑推出根尖孔的实验观察与比较

目的 观察手用不锈钢K锉和机用Profile镍钛锉用于根管预备时碎屑推出根尖孔的现象,比较其推出的碎屑量并讨论根管预备与碎屑推出根尖孔的关系.方法 将60颗离体牙随机分为2组,分别以手用不锈钢K锉或机用Profile镍钛锉进行根管预备.观察碎屑推出根尖孔的过程,收集碎屑后称量,并对2组碎屑收集量进行统计学分析.结果 手用K锉组在个别离体牙根管预备过程中先后观察到根尖孔"蠕虫"样、"湿虫"样碎屑推出.2组都观察到"根尖水滴"现象.手用K锉组推出的碎屑量多于机用Profile镍钛锉组,两者差异有统计学意义.结论 机用Profile镍钛锉在操作过程中碎屑推出量比手用不锈钢K锉少.     

扫描电镜观察通畅器械对根尖孔的适合性

通常认为在化学-机械预备过程中建立并且保持根尖孔通畅是根管根尖部清理和消毒的一个重要步骤.本研究的目的是通过扫描电镜观察评价根管锉对离体牙根尖孔的适合性.将20颗下颌第一前磨牙分为两组:第1组,将根管锉自根管内超出根尖孔1mm,找到有紧缩感的第一支根管锉,记录锉号:第2组,使用比第1组大一号的锉.将锉固定在根管内,在扫...     

镍钛器械在3种不同运动模式下预备根管后根尖孔表面形态变化

目的:研究3种不同运动模式下镍钛器械在平解剖性根尖孔长度时预备根管后根尖孔表面形态变化。方法:收集新鲜拔除的离体牙60颗,随机分为3组,用扫描电子显微镜拍摄术前片,记录根尖孔表面形态,然后分别采用Twist File Adaptive(TFA)、WaveOne、ProTaper(机用)3种镍钛锉在平解剖性根尖孔的工作长度下进行根管预备,然后在扫描电子显微镜下拍摄术后片,记录根尖孔周围牙骨质的缺损、根尖孔偏移、根尖孔周围表面的裂纹。结果:实验组均出现根尖孔周围牙骨质的缺损、根尖孔偏移、根尖孔周围表面的裂纹。3种镍钛器械根管预备后发生根尖孔偏移、根尖孔周围表面裂纹概率的差异有统计学意义(P＜0.05),3种镍钛器械根管预备后发生根尖孔周围牙骨质缺损概率的差异无统计学意义。结论:TFA和WaveOne在进行预备根管后相比ProTaper可降低根尖孔偏移的发生率,TFA比ProTaper和WaveOne在进行预备根管后产生根尖孔周围表面的裂纹少,降低了根折的风险。     

RootZX测量仪测定根尖吸收牙齿工作长度的准确性

目的:研究RootZX全自动根管长度测量仪测定根尖区吸收牙齿工作长度的准确性。方法:将80颗离体前牙平均分成甲、乙2组,其中乙组用700#裂钻深入根尖孔钻入3mm,破坏根尖狭窄处。将2组牙齿分别置于测量槽中,使用RootZX全自动根管长度测量仪测量工作长度,计算测得的工作长度与肉眼下测量的根管长度的差值A,比较RootZX全自动根管长度测量仪测量2组工作长度的准确性。结果:RootZX全自动根管长度测量仪测量甲组的准确率为95%,测量乙组的准确率为85%,但2组准确率的差异无统计学意义(P>0.05)。结论:对于根尖狭窄区破坏的牙齿,使用RootZX全自动根管长度测量仪测量的工作长度具有较高的准确性。     

根尖周病损误诊的探讨

本文对一些容易为临床医师所忽略,又较容易混淆的,非常见的根尖周病损误诊和治疗失败原因进行了探讨。通过病例分析,作者指出:①正确判断牙髓活力是否存在,是诊断和鉴别诊断根尖周病损的重要依据。②熟悉牙体解剖,是根尖周病诊治的基础。③正确应用X线摄片技术,可避免或减少误诊。④要有整体观念,不能将根尖周围的病变,简单地认为系牙髓源性而贸然诊断为慢性根尖周炎。     

Clinical Accuracy and Precision of 3 Multifrequency Electronic Apex Locators Assessed through Micro–Computed Tomographic Imaging

IntroductionThis study aimed to compare the in vivo accuracy and precision of 3 electronic apex locators (EALs) in determining the position of the major foramen using micro–computed tomographic (micro-CT) technology.MethodsAfter access preparation of 23 necrotic or vital teeth from 5 patients, canals were negotiated, and hand files were used to determine the position of the foramen with 3 EALs: Propex Pixi (Dentsply Maillefer, Ballaigues, Switzerland), Woodpex III (Woodpecker Medical Instrument Co, Guilin, China), and Root ZX II (J Morita, Tokyo, Japan). After fixing the silicon stop to the file, teeth were extracted and scanned in a micro-CT device with and without the instrument inserted into the canal. Data sets were coregistered, and the accuracy and precision of the EALs were determined at a tolerance level of ±0.5 mm by measuring the distance from the tip of the instruments to a tangential line crossing the margins of the foramen. Statistical comparisons were performed using Friedman with post hoc related samples sign and Spearman tests (α = 5%).ResultsA significant difference was detected comparing the accuracy of Root ZX II (100%), Woodpex III (86.96%), and Propex Pixi (52.17%) (P < .05). There was a lack of significance in the relationship between the pulp status and the accuracy of the tested EALs (P > .05). Propex Pixi was significantly less precise than Root ZX II (P < .05), whereas no difference was found between Woodpex III and Root ZX II or Propex Pixi (P > .05).ConclusionsEALs presented similar precision, but Woodpex III and Root ZX II showed better accuracy to determine the position of the apical major foramen than Propex Pixi.     

2种根管预备终止点对术后疼痛的影响

目的 评价根管预备中2 种不同根管预备终止点对术后疼痛的影响. 方法 需做根管治疗的患者118例用Endo Pilot根测仪进行根尖定位,随机分成2组:A组(59例),根管预备终止点位于根测仪指示"弧形基线"上最高点(蜂鸣声35次/min);B组(59例),根管预备终止点位于根测仪指示"弧形基线"下最低点(蜂鸣声65次/min). 用疼痛视觉模拟评分法( visual analogue scale,VAS)的分值,记录2组患者根管预备前和术后12 h、1 d、2 d、3 d、1周疼痛情况. 结果 118颗患牙疼痛的总发生率为18. 6%,其中A组为16. 9%(10/59),B组为20. 3%(12/59),2组疼痛发生情况差异无统计学意义(P>0. 05);A、B 2组在各时间段VAS疼痛分值差异无统计学意义(P>0. 05). 结论 根管预备中2种根管预备终止点对术后疼痛无明显影响.     

Influence of Apical Diameter on the Outcome of Regenerative Endodontic Treatment in Teeth with Pulp Necrosis: A Review

Introduction

The aim of this review was to evaluate whether the apical diameter of teeth with necrotic pulp affects the outcomes of regenerative endodontic treatment and to determine the minimal apical size needed to obtain proper pulp revascularization.

年轻恒牙根尖诱导成形术后根尖发育的影响因素

目的观察年轻恒牙根尖诱导成形术后根尖发育情况和根尖封闭愈合类型,分析影响根尖发育的临床因素。方法收集行根尖诱导成形术的患牙35颗,详细观察患牙术前、术中、术后的X线片,记录根尖发育情况和根尖封闭愈合类型,分析根尖诱导成形术后根尖发育的影响因素。结果 35颗患牙有21颗患牙根尖发育完成,其中Ⅰ类愈合7颗,Ⅱ类愈合14颗;有14颗患牙未显示牙根发育,其中Ⅲ类愈合13颗,Ⅳ类愈合1颗。由于根尖段残留有生活的牙髓使诱导剂显示欠填是根尖发育的保护因素（OR=0.047,P=0.009）,而根尖周低密度影成为根尖发育的危险因素（OR=12.113,P=0.004）。结论根尖段残留的生活牙髓和牙乳头可促进牙根继续发育,根尖周病变影响根尖发育。     

Accuracy of Root ZX II in locating foramen in teeth with apical periodontitis: an in vivo study

Introduction

This study was conducted in vivo to investigate the accuracy of Root ZX II in locating the apical foramen in teeth with apical periodontitis (AP).

Methods

Twenty-seven single-root teeth scheduled for extractions were selected; in AP group, there were 12 teeth with pulp necrosis and radiographic evidence of apical lesions, and VT group consisted of 15 vital teeth. After endodontic access, the coronal portion of the canal was flared, and electronic measurement was performed by using a 15 K-file until the device level reading “APEX” was reached. The file was fixed in place, and the tooth was extracted. The apical third of the root was shaved until exposure of the file. The distance from the file tip to the most coronal border of the apical foramen was obtained.

Results

The mean distance in AP group was +0.117 (standard deviation, 0.373) and in VT group was -0.105 (standard deviation, 0.218). The unpaired t test showed no difference between the groups when comparing the mean distances (P > .05). The apical foramen was accurately located within ±0.5 mm in 83% of the teeth in AP group and in 100% of VT group. Statistical analysis showed no difference between the groups (P = .1092).

Conclusions

The Root ZX II device was accurate in locating the apical foramen regardless of the presence of AP.     

Not All Electronic Foramen Locators Are Accurate in Teeth with Enlarged Apical Foramina: An In Vitro Comparison of 5 Brands

Introduction

Electronic working length measurement during root canal treatment in teeth with enlarged apical foramina is a challenge. The aims of this in vitro study were (1) to assess the influence of foramen widening on the accuracy of 5 different electronic foramen locators (EFLs) and (2) to compare the accuracy of EFLs in different foramen sizes.

Methods

The following EFLs were used: MiniApex, Root ZXII, iPex, Propex II, and Elements Apex Locator. Each EFL was used in 3 groups (n = 20) of extracted teeth, with foramen diameters of 0.27 mm (G27), 0.47 mm (G47), and 0.72 mm (G72). Working length was measured according to manufacturer's instructions and compared with visual measurements (control method). Results were classified as accurate (equal or differences ≤ 0.05 mm) or inaccurate (differences > 0.5 mm).

Results

In G27, all EFLs yielded accurate findings (intragroup reliability; Fisher exact test, P < .05), compared with only MiniApex, Root ZXII, and Elements Apex Locator in G47 and G72. MiniApex, Root ZXII, and Elements Apex Locator were similarly accurate regardless of foramen size. iPex and Propex II were the least accurate among the devices tested, and foramen diameter influenced their accuracy, with greater diameters yielding poorer EFL performance.

Conclusions

Foramen diameter did not influence the accuracy of MiniApex, Root ZXII, and Elements Apex Locator EFLs. iPex and Propex II showed decreased accuracy as foramen size increased.     

Transient apical breakdown following tooth luxation

Abstract –  Transient apical breakdown is a sequelae of certain dental traumatic injuries where the injured tissues undergo a spontaneous process of repair with no permanent damage to the pulp. Misdiagnosis of this condition may result in unnecessary endodontic treatment. Presented is a case of transient apical breakdown following a subluxation injury of a maxillary central incisor in a 15-year-old girl. Four months after injury, coronal discoloration, periapical radiolucency as well as negative pulp responses to cold and electric tests were still recorded. Subsequently, the tooth spontaneously regained its original shade and the pulp responded normally to pulp sensitivity tests. Methods for early diagnosis of transient apical breakdown are discussed.     

根尖诱导成形术治疗感染型畸形中央尖的临床观察

目的：研究感染型畸形中央尖患牙根尖诱导后的临床疗效,并观察不同根尖孔形状对牙根闭合的影响。方法：选择59个己发生牙髓感染的畸形中央尖患牙,采取根尖诱导促进牙根发育、根尖闭合。结果：经2年追踪观察,术后患牙100％临床症状消失,93．22％完成根尖封闭。14个根尖内聚型患牙术后根尖发育完成,平均闭合时间6．64个月;19个根尖平行型,8个根尖发育完成,另11个根管腔无缩窄,但根尖达到闭合,平均闭合时间10．58个月：26个根尖喇叭口型3个根尖闭合,19个在根尖孔处形成钙化桥,4个形成根管内不规则钙化桥,平均闭合时间16．91个月。随着治疗进展,患牙根尖孔直径逐步缩窄,术前根尖孔直径平均1．99mm,术后平均0．88mm,但仍高于健康对照牙（p：0．03,〈0．05）。结论：感染型畸形中央尖经根尖诱导治疗可获得良好预后。不同根尖孔形态的畸形中央尖其临床疗效无明显差别。术前根尖内聚型或平行型患牙,术后根尖发育接近生理性闭合状态,术前根尖孔呈喇叭口型者可影响牙根发育成正常根尖形态。