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。     

下颌第一前磨牙根管峡部的显微CT研究

目的:运用显微CT研究非单根管的下颌第一前磨牙根尖0～6 mm区域根管峡部出现的位置和发生率,为提高根管治疗和根尖外科手术的成功率提供解剖学依据。方法:从147颗下颌第一前磨牙中挑选出非单根管的40颗,用显微CT以15μm分辨率、30μm层厚扫描及软件三维重建,观察并记录根尖0～6 mm区域各横截面的峡部形态及分布情况,并对根管系统的解剖形态三维重建后,进行二维、三维图像分析。结果:非单根管的下颌第一前磨牙距根尖0～6 mm区域内根管峡部的发生率(%)由根方向冠方以每1 mm为间距依次为:6%、18.5%、78.6%、80%、79.2%、72.5%。结论:非单根管下颌第一前磨牙根管峡部在距根尖3～6 mm区域高发,其中距根尖3～4 mm区域发生率最高。     

显微CT法研究上颌第一磨牙根管系统解剖形态

目的 使用显微CT研究上颌第一磨牙根管系统解剖形态.方法 随机收集33颗上颌第一磨牙,使用显微CT扫描后重建根管系统.观察并记录各牙根根管形态和分支根管的发生数目、位置.记录各根管口位置并测量根管口间的距离和所成角度.在距离根尖1、2和3mm处进行虚拟切割,记录断面上分支根管暴露情况.结果 上颌第一磨牙近颊根第二根管发生率为75.76%.近颊根发生分支根管为71.64%;近颊根分支根管发生率为72.73%.91.04%的分支根管发生于根尖1/3段,近颊根距根尖3mm处截面分支根管暴露率为12.12%.近颊根第一、第二根管口间的距离为(1.60±0.41)mm.结论 上颌第一磨牙根管系统解剖形态复杂,近颊根根管形态存在较大解剖变异.     

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。     

显微CT在根管峡区研究中的应用

目的：探讨显微CT在根管峡区形态定性定量研究中的应用。方法：收集单根上颌前磨牙,显微CT扫描及三维重建后,筛选出五颗有根管峡区的牙,分析峡区横断面百分比以及横断面峡区类型,测量峡区至釉牙骨质界距离（DcEJ）以及至解剖根尖距离（DApex）,并分析峡区根管的结构模型指数（SMI）。结果：峡区横断面百分比为81．8％,其中完全峡区（CI）占72．8％,部分峡区（PI）占9％;DCEJ为（0．79±0．55）mm,DApex为（1．55±0．86）m;峡区根管的SMI为1．20±0．43。结论：显微CT结合三维重建技术能够对根管峡区形态进行定性定量分析,是研究根管峡区较理想的方法。     

上颌第一、第二恒磨牙牙根和根管系统的锥形束CT研究

目的：运用锥形束CT（CBCT）观察中国人群双侧上颌第一、第二磨牙的牙根和根管系统的解剖形态,为临床根管治疗提供依据。方法：选择200名患者的双侧上颌第一、第二恒磨牙（上颌第一恒磨牙354颗、上颌第二恒磨牙360颗）的CBCT扫描数据,使用NNT软件分析上颌第一、第二恒磨牙的牙根数、根管数、根管分型以及双侧对称情况。结果：上颌第一、第二磨牙主要为三根（99.44%和84.44%）。上颌第二磨牙的单根和双根较多见（15.28%）,其根管系统形态复杂,在根尖区有融合趋势。上颌第一磨牙的根管系统主要为3根四根管（78.97%）。上颌第二磨牙的三根管和四根管发现率接近（分别为47.37%和51.64%）。上颌第一磨牙的近颊根管系统主要根管分型为：Ⅳ型（57.79%）、Ⅱ型（19.83%）和Ⅰ型（15.58%）。上颌第二磨牙的近颊根管系统主要根管分型为：Ⅰ型（48.14%）、Ⅳ型（30.43%）和Ⅱ型（17.39%）。上颌第一、第二磨牙的远颊根和腭根主要为单根单根管,存在少量和罕见的变异。上颌第一、第二磨牙近颊根的根管数目和根管分型左右对称。结论：上颌第一磨牙近颊根管系统变异普遍存在,MB2根管为其主要的变异形式。上颌第二磨牙牙根数目和根管形态变异类型多,单根牙和双根牙的根管走向复杂多变。CBCT可以为识别根管形态提供准确依据。     

上颌第二前磨牙根管峡发生率和位置的研究

目的：研究离体单根的上颌第二前磨牙根尖1—6mm处根管形态及根管峡部的发生率和位置的情况。方法：收集离体上颌第二前磨牙60颗，自根尖开始，片切去除1mm牙根后，用美蓝染色根切面，在显微镜下观察并记录各横截面的根管数和峡部分布情况。在距根尖1～6mm区域内每隔1mm处重复以上操作。结果：上颌第二前磨牙双根管率是41．67％；根管峡部在距根尖4mm水平最高。结论：上颌第二前磨牙根管峡部在距根尖3—5mm区最高发；根尖1～6mm区域根管系统形态复杂。     

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     

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。     

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。     

A preliminary in vitro study of the incidence and position of the root canal isthmus in maxillary and mandibular first molars

AIM: To investigate in vitro the incidence and position of the root canal isthmus in extracted mesiobuccal roots of maxillary and mesial roots of mandibular first molars. METHODOLOGY: Fifty maxillary and 50 mandibular molars were included in the study. The mesiobuccal roots of maxillary molars and the mesial roots of mandibular molars were sectioned from their crowns in the furcation region and embedded in clear resin. Transverse serial 1-mm-thick sections from the apical 6 mm were prepared. The apical side of each section was stained with India ink and observed through a light microscope. The sample images were saved to disk using a digital camera and the root canals in terms of the number present and the incidence and classification of isthmuses. RESULTS: In the mesiobuccal root of the maxillary first molars, 70% had one canal, whereas 29.5% had two canals. In the mesial root of mandibular molars, 41% had one canal, whereas 59% had two canals. In some sections, more than two canals were found close to the apical foramen. The isthmus incidence was greatest 3-5 mm from the apex. In teeth having two canals, a complete or partial isthmus was frequently observed in the sections between 3 and 4 mm from the apex. Of the isthmuses present, 22% were complete and 37% partial in mandibular molars and 17.3% were complete and 11.7% partial in maxillary molars. CONCLUSIONS: The incidence of isthmus in the mesiobuccal root of the maxillary first molars and in the mesial root of the mandibular first molars was high, particularly in sections 3-5 mm from the apex. Cleaning the isthmus is a major challenge during root canal treatment.     

Root and canal morphology of Thai maxillary molars

AIM: To investigate the root and canal morphology of 268 maxillary permanent molars collected from an indigenous Thai population. METHODOLOGY: The cleaned teeth were accessed, the pulp dissolved by sodium hypochlorite under ultrasonication, and the pulp system injected with Indian ink. The teeth were rendered clear by demineralization and immersion in methyl salicylate. The following observations were made: (i) number of roots and their morphology; (ii) number of root canals per root; (iii) root-canal configuration in each root using Vertucci's classification with additional modifications; and (iv) presence and location of lateral canals and intercanal communications. RESULTS: All the maxillary first and second molars had three separate roots. Only, half (51%) of the maxillary third molars had three separate roots; the other half had fused or conical roots. The majority of the distobuccal (98.1-100%) and palatal (100%) roots had type I canals. Over half of the mesiobuccal roots of first (65%) and second (55%) molars had two canals. The most common (44.2%) canal configuration in mesiobuccal roots of first molars was type IV (two canals, two foramina). A variety of canal types were found in the mesiobuccal roots of second molars. Maxillary third molars showed the greatest diversity of canal morphology. There was an increase in the prevalence of lateral canals towards the apical part of the roots and intercanal communications were present in 16% of each of first, second and third Thai maxillary molars. CONCLUSIONS: The mesiobuccal roots of Thai maxillary molars possessed a variety of canal system types. Over 50% of the first molars had a second mesiobuccal canal. The palatal and distobuccal canals mainly had type I canals. Only, a small proportion (7.3-13.3%) of the roots exhibited lateral canals which were the most common in the apical third     

上颌第一磨牙根管系统的研究

目的 观察上颌第一磨牙的根管系统。方法 制备50个上颌第一磨牙透明牙标本,显露根管系统的空间构型,在体视显微镜下观察并记录根管系统的形态,结合应用加以统计。结果 ①上颌第一磨牙近中颊根单根管率为66%,其中Ⅰ型占38%,双根管率为34%,远中颊根Ⅰ型占74%,腭根Ⅰ型占94%。②根管侧支、根尖分歧、根尖分叉多见于近颊根,在近颊根的发生率为40%, 远颊根的发生率为24%,腭根的发生率为6%,发生部位多见于根尖1/3。结论 上颌第一磨牙近颊根的根管系统最为复杂,根管变异较远颊根多,腭根变异最少。     

Root canal anatomy of maxillary first and second permanent molars

AIM: The aim of this investigation was to study the root canal anatomy of maxillary first and second molar teeth from an Irish population sample using a clearing technique. METHODOLOGY: Eighty-three extracted permanent maxillary right first molars and 40 permanent right maxillary second molars were included in this investigation. The specimens were demineralized and then cleared using methyl salicylate. The following observations were made: number of roots, prevalence of fusion, types of root canals using Vertucci's classification, presence and position of lateral canals, presence and position of transverse anastomoses, number and position of apical foramina and the frequency of occurrence of apical deltas. RESULTS: Eleven per cent of maxillary first molars and 43% of maxillary second molars had fused roots. A total of 78% of mesiobuccal roots in maxillary first and 58% in maxillary second molars had two canals. Sixty-two per cent of maxillary first and 50% of maxillary second molars had two apical foramina. There was a significant inverse relationship between age and the occurrence of two canals and between age and the occurrence of transverse anastomoses in both tooth morphotypes (P < or = 0.05). CONCLUSIONS: It is concluded that a significant proportion of the first and second molar specimens studied had two canals in the mesiobuccal root (78% and 58%, respectively) and that the occurrence of two canals and transverse anastomoses decreased significantly with increasing age.     

Root canal morphology of the mesiobuccal root in maxillary first molars of a Jordanian population

This in vitro study investigated the presence of second (MB2) root canals and the number of apical foramina found in mesiobuccal roots of the permanent maxillary first molars; in addition, the study evaluated the effectiveness of magnification to detect MB2 canals. One hundred extracted maxillary first molars were collected from Jordanian patients. The number of roots (as well as their morphology) was investigated. The number of canal orifices in mesiobuccal root was assessed, with and without magnification, and findings were compared. The number of apical foramina and the distance between mesiobuccal and second canal orifices were investigated under magnification. Of the 97 specimens that were subject to additional investigation, all teeth had three separated roots, except for three specimens that had either mesiobuccal or distobuccal roots fused with the palatal root. The number of MB2 canals that were detected increased from 55 (56.7%) to 61 (62.9%) teeth when magnification was used. Within the limits of this in vitro study, it was concluded that the Jordanian population had a high percentage of MB2 canals in the mesial buccal roots. Moreover, the use of clinically used magnifying devices increased the number of MB2 canals detected.     

Root canal morphology of the mesiobuccal root of maxillary first molars: a micro-computed tomographic analysis

Aim  To investigate ex vivo , the root canal morphology of the MB root of maxillary first molar teeth by means of micro-computed tomography.
Methodology  Thirty extracted intact human maxillary first molar teeth were selected for micro-tomographic analysis (SkyScan 1072, Aartselaar, Belgium) with a slice thickness of 38.0 μm. The following data regarding the MB root were analysed and recorded: number and type of root canals, prevalence of isthmuses, prevalence of intercanal connections, presence of accessory canals, presence of loops and number of apical foramina.
Results  The MB2 canal was present in 80% of specimens and was independent in 42% of these cases. When present, the MB2 canal merged with the MB1 canal in 58% of cases. Communications between the two canals were found in all specimens, with isthmuses in 71% of the cases. These communications and isthmuses were respectively in 42% and 54% of the cases in the coronal third, in 59% and 79% of the cases in the middle third and in 24% and 50% of the cases in the apical third. A single apical foramen was found in 37% of specimens, two apical foramina were present in 23% of the cases, with three or more separate apical foramina occurring in 40% of the specimens.
Conclusions  The MB root canal anatomy was complex: a high incidence of MB2 root canals, isthmuses, accessory canals, apical delta and loops was found.     

山东地区人离体上颌第二恒磨牙牙根及根管形态观察

目的:观察山东地区人上颌第二恒磨牙牙根及根管形态的解剖特点。方法:于山东地区收集离体上颌第二恒磨牙118个,观察牙根形态及类型;应用透明牙标本法观察根管形态并按Vertucci八分类法对其进行分类。结果:118个上颌第二恒磨牙中以3根分离者为主,占91.52%,牙根融合者共10例,占8.47%,其中融合成2根者为5.08%,主要为近中颊根与远中颊根融合;融合成单根者为3.39%。透明牙标本法下观察根管系统,上颌第二恒磨牙远中颊根及腭根根管以Ⅰ型为主;近颊根根管仅44.95%为Ⅰ型,近颊根第二根管(the second mesiobuccal canal,MB2)的发生率达51.38%。结论:山东地区上颌第二恒磨牙的牙根具有多样性,以3根分离根形态为主,同时可发生各种融合根;其根管形态复杂,MB2的发现率较高。     

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.     

离体上颌磨牙近中颊根第二根管出现率的研究

目的运用透明标本观察法、螺旋CT薄层扫描技术和牙根硬组织切片观察法研究中国人离体上颌第一、二磨牙近中颊根第二根管（MB2）的出现率。方法分别收集离体上颌第一磨牙216例、第二磨牙334例，均随机分为两组：A组制成透明标本；B组标本经螺旋CT扫描后，自根尖开始每隔1mm横切牙根。所有离体牙标本均在牙科手术显微镜下观察并记录近中颊根的根管数目。结果透明标本观察法所得的上颌第一、第二磨牙MB2出现率分别为81．48％和49．70％；螺旋CT扫描技术所得的结果分别为77．78％和47．31％；牙根硬组织切片法所得的结果分别为88．89％和53．89％。上颌第一磨牙MB2出现率高于第二磨牙，其差异有统计学意义（P〈0．05）。同一牙位不同实验方法间的结果差异均无统计学意义（P〉0．05）。结论上颌第一、二磨牙MB2出现率高，提示临床医师应努力探查该根管，以提高上颌磨牙根管治疗的成功率。