1282个恒牙根尖孔形态的显微解剖及其临床意义

为研究恒牙根尖孔的形状和孔径与牙位和牙根的关系，采用ＸＴＬ－２型连续变倍体视摄影显微镜，对１２８２个恒牙根尖孔的形状和孔径进行了观察和摄影。结果提示，１２８２个根尖孔中圆形和椭圆形者占９４．７７％（１２１５／１２８２），证明根尖孔的形态符合血管或（和）神经进入硬组织的形态学规律。     

三根型下颌第一恒磨牙根尖解剖结构的显微CT观测

目的 揭示三根型下颌第一恒磨牙根尖解剖特点,以期为临床进行根管治疗提供依据.方法 从江苏省吴江市第一人民医院口腔科门诊采集中国汉族患者拔除的下颌第一恒磨牙122颗,选择20颗三根型下颌磨牙(三根组)及25颗双根型下颌磨牙(双根组)进行显微CT扫描及三维重建.Mimics 10.01软件界面下观测根尖部的解剖结构,测量根尖狭窄的长、短径,根尖孔、根尖狭窄与根尖端的距离;两组牙齿不同根管间根尖狭窄直径及其与根尖孔、根尖端距离的比较采用单因素方差分析及LSD-t检验,以P＜ 0.05为差异有统计学意义.结果 近颊根管根尖孔最多见于根尖远中侧(三根组10个,双根组6个),近舌根管多见于舌侧(三根组及双根组各8个);远颊根根尖孔多位于根尖远中舌侧(10个),远舌根根尖孔常偏向颊侧(7个);双根组远中根管根尖孔大多偏向远中(11个).典型的沙漏状根尖狭窄出现率为53％( 80/151).三根组远颊根管根尖狭窄的长、短径分别为(0.32±0.09)、(0.25±0.05) mm,显著大于远舌根管[长、短径分别为(0.27±0.08)、(0.22±0.06) mm,P＜ 0.05]及近舌根管[长、短径分别为(0.24±0.06)、(0.19±0.06)mm,P＜ 0.01].三根组根尖孔至根尖狭窄及根尖端的平均距离分别为(0.67±0.32)和(0.49±0.28) mm,根尖狭窄至根尖端平均距离为(1.01±0.34) mm.结论 三根型下颌第一恒磨牙根尖孔往往偏离根尖端,根尖狭窄在远颊根管最宽大;根尖狭窄、根尖孔及根尖端间距的测量可以为根管治疗时确定工作长度提供参考.     

猪第一恒磨牙根尖定位的解剖学研究

目的为更好地利用猪颌来训练口腔医学生掌握根尖外科手术的方法,研究猪第一恒磨牙根尖定位的解剖学特点,为实验教学提供依据。方法选取第一恒磨牙都已完全萌出、恒牙列完整的48个猪一侧下颌作为实验对象,用游标卡尺测量猪第一恒磨牙全长(根尖在术区骨面的投影位置至牙尖的距离)、根尖至术区侧的距离、近远中径、颊舌径和临床牙冠长度,用SPSS软件对数据进行各种统计分析。结果猪第一恒磨牙全长平均值为27.98mm。根尖至术区侧的距离平均值为4.53mm。对同一颗牙的近远中径、颊舌径和全长进行直线回归分析,其回归方程差异均有统计学意义。对同一颗牙的临床牙冠长度与全长进行直线回归分析,对同一颗牙的近远中径和颊舌径与根尖至术区侧的垂直距离进行直线回归分析,其方程差异均不具有统计学意义。结论在利用猪颌作为模型进行根尖外科手术实验中,可根据牙的近远中径和颊舌径,参考本研究计算出的猪第一恒磨牙全长的平均值,粗略估计根尖在术区骨面投影龈向的位置。     

温州地区人上颌第一恒磨牙牙根解剖的研究

目的:了解温州地区人上颌第一恒磨牙牙根解剖基本特点。方法:收集60个温州地区人上颌第一恒磨牙,肉眼观察牙根外形、根尖孔数目、类型;游标卡尺测量牙根长度指标、根尖孔到牙根顶点的距离;透明牙标本法观察根管系统。结果:上颌第一恒磨牙55.4%根尖孔不在根尖顶点,近中颊根双根管率为61.6%,3根管率为1.7%。结论:温州地区人上颌第一恒磨牙牙根、根管形态复杂,应给予足够的重视。     

根尖孔大小对Root ZX准确性影响的体外研究

目的研究根尖孔大小对Root ZX测量准确性的影响。方法采用离体牙模型,在根尖狭窄完整和破坏的情况下,分别测量实际根管长度（L）、实际根管工作长度（L′）、电测根管长度（L1）、电测根管工作长度（L2）和根尖孔面积（S）,并采用SPSS 12.0软件对根尖孔面积与Root ZX电测法测量偏差的相关性进行分析。结果在根尖狭窄完整情况下,根尖孔面积与Root ZX测量准确性之间无显著相关性（P>0.05）;当根尖狭窄破坏后,根尖孔面积与Root ZX测量准确性有显著的负相关关系（P<0.001）,直线回归方程为ΔL2=- 0.623+6.596S。当测量误差设定在0.5 mm时,根尖孔开口面积为0.135 mm2。结论根尖狭窄被破坏后,根尖孔大小对Root ZX测量准确性有影响。临床上对根尖有吸收破坏或根尖未发育完全的患牙采用Root ZX电测法测量时,应谨慎参考根管工作长度值。     

恒牙根尖部侧孔形态的显微解剖研究

目的 研究恒牙根尖部侧孔,为临床和国人提供解剖学资料。方法 采用ＸＴＬ－２型链续变倍体视摄影显示微镜,对１５０２个恒牙根尖部出现的２３０个侧孔的形状和孔径进行观测。结果 ２３０颗恒牙根尖部侧孔的形状可分为４型：圆形１４１个,占６１．３０％;椭圆形８５,占３６．９６％;肾形３个,占１．３０％;不规则形１个,占０．４３％。结论 恒牙根尖部侧孔的孔径为根尖孔的一半,并约有１／７的恒牙出现根尖部侧孔。     

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.     

上颌第一恒磨牙髓室底及根尖孔的观察

目的 研究上颌第一恒磨牙的髓室底形态,根管口的形态,根管口及根尖孔的数目和位置分布。方法 106颗离体上颌第一恒磨牙,暴露其髓室底,并用苏木素将根尖区染色,用肉眼观察法结合用光滑髓针、15号根管扩大器等探查以明确根管口数,根尖孔数及其位置分布。结果 上颌第一恒磨牙的髓室类似一个底在颊侧的三角形,38.68%为三根管口,61.32%为四根管口,左右分布无差异,四根管口者含一个远中颊侧根管口,一个腭侧根管口,近中颊侧根管又分偏颊、偏腭侧两根管口;远中颊、腭根的根尖均为单孔,近中颊根的双根尖孔率为51.8%,61.54%的根尖孔为侧方开口。结论 上颌第一恒磨牙的开髓洞形应为偏向近中的圆三角形,近中颊根的双根管检出率较高。     

上颌第一恒磨牙80颗牙体解剖的离体研究

目的 :了解上颌第一恒磨牙牙体解剖基础知识。方法 :肉眼观察近颊根外形 ,牙合面磨耗程度 ,髓室底形态 ,根尖孔数目及类型 ;游标卡尺测量各项长度指标及根尖孔到牙根顶点的距离 ;透明牙标本法观察根管系统。结果 :上颌第一恒磨牙近颊根Ⅲ型根尖孔 2 6.9% ;双根管率为 5 6.2 5 % ,三根管率为 7.5 %。结论 :上颌第一恒磨牙近颊根存在着较高的多根管率 ( 63 .75 % ) ,应该引起临床医生的高度重视     

下颌第一恒磨牙根尖形态的显微CT研究

目的:使用显微CT研究下颌第一恒磨牙根尖5 mm形态。方法:采用显微CT对152颗离体下颌第一恒磨牙进行扫描,利用3-D软件三维重建根尖5 mm形态。记录根尖孔和侧副孔数目、峡区发生和分型。结果:94.08%下颌第一恒磨牙有两个单独牙根,61.84%有3个根管。60.91%的近中根有两个根尖孔。37.27%的近中根和33.01%的远中根有侧副孔。73.68%的牙出现峡区,峡区形态以IV型最为常见。结论:下颌第一磨牙根尖形态复杂,常规根管治疗和根尖手术应考虑其复杂性。     

第一磨牙冠方预展后根管弯曲度的改变及对初锉选择的影响

目的探讨冠方预展后离体第一磨牙各根管弯曲度的变化及对初锉选择的影响。方法上下颌离体第一磨牙各30颗,共163个根管,平行投照法拍摄X线片,用Schneider法测量根管弯曲度,用GG钻进行冠方预展,比较预展前后根管弯曲度和初锉大小的变化。结果冠方预展后弯曲度比术前减小4.96°±3.85°,差异有统计学意义(P<0.05)。根管原始弯曲度越大,预展后弯曲度的改变也越大。冠方预展后各根管初锉号数比术前增大,平均为0.06±0.05mm。结论冠方预展去除了根管上段的干扰,减小了根管的弯曲度,增大了初锉号数,使根管根尖部的预备变得容易,有效。提倡在根尖部预备之前先行冠方预展。     

Morphology of apical foramen in permanent molars and premolars in a Turkish population

Abstract

Objective: To determine the number, shape and diameter of minor apical foramina, the distance between apical foramina and anatomical apex and the frequency of accessory foramina in a Turkish population. Materials and methods: Eight hundred permanent maxillary and mandibular teeth were collected. The roots were stained with methylene blue and the apices were examined with a stereomicroscope (×40) and transferred to a computer to perform the measurements using Adobe Photoshop software. Results: The incidence of one apical foramen was highest in distobuccal roots of the maxillary first molars and was lowest in the maxillary first premolars with single roots. The distance of deviation in all the teeth was between 0.271–0.519 mm. The frequency of accessory foramina was between 30–70% for the various tooth types. Conclusions: The results of this in vitro study indicate that the morphology of apical foramina in this Turkish population may present highly complex anatomical variations.     

The position of the apical foramen of the permanent incisors

The position of the apical foramen in relation to the anatomical root apex is of considerable importance to the dentist, especially when the level of obturation of the root canal is determined through tooth length calculated radiologically. The main objective of this study was to determine in upper permanent incisor teeth, the position of foramen/foramina relative to the anatomical apex.
In 635 permanent upper incisors, the results of this study showed 54.3 per cent with the foramen coincident with the root apex, and 45.7 per cent where the root apex and the foramen were non-coincident. The average distance of the foramen from the root apex in the latter group was 0.35 mm and it ranged from 0.1 to 1.2 mm. The significance of these findings is discussed in relation to the apical termination of debridement and obturation of root canals.     

根尖周吸收对Rapex5电子根尖定位仪精确性的影响

目的：探讨根尖周吸收对Rapex5电子根尖定位仪（EAL）精确性的影响。方法：根据病史和X线片,选择40例有根尖周吸收的根管为实验组,40例无根尖周吸收的根管作为对照组。用Raypex5测量根管工作长度,与离体直视根尖剖面最狭窄处测得的根管长度进行比较。以距根尖狭窄-0.5～0 mm为准确。结果：实验组根管工作长度的准确率为67.5%,比对照组（90%）明显降低,差异有显著性（P〈0.05）。结论：Raypex5测定根管工作长度的准确率较高,根尖周吸收对其精确性有一定影响。     

Topographical evaluation of the major apical foramen in permanent human teeth

Aim To determine the distance from the anatomical root apex to the major apical foramen and the position of the major foramen on the root apex. Methodology Crowns of 926 human teeth were sectioned at the cementum‐enamel junction. Specimens were mounted on microscope slides for measurement parallel to the long axis of the teeth. The major foramen was identified as the largest‐diameter opening at the root apex. A total of 1331 root specimens were evaluated using an optical stereomicroscope to an accuracy of 0.01 mm at 40 × (±10) magnification. The distance from the anatomical apex to the most apical point of the major foramen was measured, and its location (central, buccal, lingual, mesial and distal) was recorded. Results The mean distance between the major foramen and the anatomical root apex was 0.69 mm; the mean distance was larger in posterior teeth (0.82 mm) and smaller in anterior teeth (0.39 mm). A wide range of anatomical apex to major foramen distances were observed in all tooth groups: the greatest distance was in maxillary molars (0.95 mm) followed by mandibular pre‐molars (0.87 mm) and mandibular molars (0.80 mm). The major foramen was at the tip of the root in 40% of teeth. The most frequent deviations of the foramen were to the buccal (20%) and distal (14%). Conclusion In this sample of teeth without apical resorption the distance between the major foramen and the anatomical root apex was always <1 mm. Deviation of the major foramen from the anatomic apex varied widely amongst tooth groups.