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。     

根管显微镜在发现离体上颌第一磨牙近中颊根第二根管中的作用

目的:比较肉眼和应用根管显微镜条件下,离体上颌第一磨牙近中颊根第二根管(MB2)的发现率,为推广根管显微镜的临床应用提供依据.方法:离体上颌第一磨牙共105个,分别肉眼下使用传统开髓口、改良开髓口,根管显微镜下探查寻找MB2,记录MB2发现率.结果:传统开髓口、改良开髓口和根管显微镜条件下,MB2的发现率分别为45.71%,54.29%,82.86%,肉眼下传统开髓口和改良开髓口MB2的发现率与应用根管显微镜时MB2的发现率存在显著差异(P<0.05).结论:应用根管显微镜可以极大地提高MB2的发现率.     

上颌磨牙近颊根根管类型及其临床意义

目的：运用透明标本法观察离体上颌第一、二磨牙近颊根根管形态，并进行分类和讨论其临床意义。方法：收集离体上颌第一、二磨牙共275颗，制成透明标本。根管显微镜下观察、记录近颊根的根管数目、走向、融合和分支情况，并进行分类。结果：①上颌磨牙近颊根管形态各异，可概括为八种类型，双根管中以2-1型和2-2型多见；双根管率在第一磨牙和第二磨牙分别为81．48％和49．7％。②近颊根主根管(MB)和近颊根第二根管(MB2)的尖1/3多弯向远中，MB2在近根管口1mm-3mm处有一斜向近中的弯曲点。结论：掌握上颌磨牙近颊根1-2型、2-1-2型和1-2-1型根管形态，是提高上颌磨牙根管治疗技巧和成功率的关键；有效去除根管近中壁部分突起的牙本质，以减小冠1/3处的弯曲度，可望提高MB2根管的探通率。     

上颌磨牙近中颊根的寻找和扩通

目的：寻找并尽量扩通上颌磨牙近中颊根第二根管，统计其发生率及通畅率。方法：离体上颌磨牙11颗，开髓、拔髓，寻找并尽量扩通近中颊根第二根管即MB2，根管预备、充填，拍片。统计其发生及发现率。临床上对146颗上颌磨牙开髓、拔髓，寻找并尽量扩通近中颊根第二根管即MB2，根管预备，充填，拍片。结果：离体牙10颗，上颌第一磨牙近中颊根第二根管发现率为60％，通畅率为50％。94颗上颌第一磨牙，近中颊根第二根管发现率为44.68％.通畅率为29.78％，52颗上颌第二磨牙，发现率为11.53％，通畅率为7.69％。结论：上颌第一磨牙近中颊根第二根管的发生率较高，其寻找、定位及扩通尽管有一定的困难，临床医生仍应注意寻找，以提高上颌磨牙根管治疗的成功率。     

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。     

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。     

上颌第一磨牙近中颊根MB2根管研究

目的：观测上颌第一磨牙近中颊根MB2的存在率,根管口的位置及形态。方法：采用牙体硬组织切片机对拔除的上颌第一磨牙进行连续横断切片,并在显微镜下观测其近中颊根第二根管存在情况,根管口位置及根管形态。结果：220个上颌第一磨牙中有81个存在近中颊根第二根管,存在率为36．81％,近颊根第二根管口横切面形态为圆形或卵圆形,近颊第二根管口与近颊第一根管口,远颊根管口和腭根管口的位置关系呈斜四边形。结论：上颌第一磨牙近中颊根第二根管存在率较高,其开髓形状应为斜四边形。     

上颌磨牙近中颊根第二根管出现率及临床意义

目的研究离体上颌磨牙近中颊根第二根管（second mesiobuccal canal，MB2）在上颌第一、第二磨牙的出现率。方法离体上颌第一磨牙62颗和第二磨牙70颗，采用髓室底探查法和透明牙标本法分别观察记数MB2。结果髓室底探查法中上颌第一、二磨牙MB2的出现率分别为80．65％和48．57％，上颌第一磨牙MB2的出现率高于第二磨牙，差异有统计学意义（χ2=14．62，P=0．00）。透明标本法中上颌第一、二磨牙MB2的出现率分别为77．42％和44．29％，上颌第一磨牙MB2的m现率仍高于第二磨牙，差异有统计学意义（χ2=15．02，P=0．02）。上颌磨牙MB2的出现率在髓室底探查法和透明标本法中分别为63．64％和59．85％，两方法间的差异无统计学意义（χ2=0．04，P=0．22）。结论上颌磨牙MB2的出现率高，且忙颌第一磨牙MB2的出现率高于第二磨牙．临床医生应努力探查该根管以提高上颌磨牙根管治疗的远期疗效。     

根管显微镜在定位上颌磨牙近颊根第二根管中的作用

目的:评价改进开髓口和应用根管显微镜(DOM)定位离体上颌第一、二磨牙近颊根第二根管(MB2)的能力.方法:收集离体上颌第一、二磨牙共550颗.在肉眼、传统三角形开髓口(N.E-1),肉眼、改进开髓口(N.E-2)和根管显微镜辅助(DOM)三种不同条件下分别探查根管,记录MB2数目.结果:N.E-1、N.E-2和DOM三种不同条件下,MB2发现率在上颌第一磨牙分别为34.26%、51.85%和78.24%;第二磨牙分别为16.17%、23.65%和41.32%.改进开髓口和使用DOM可显著提高MB2发现率,与传统开髓口间的差别有统计学意义,P＜0.05.结论:建议将上颌磨牙开髓口由传统的三角形改为斜四边形,并使用合适的放大技术和增强照明,以提高MB2发现率和治疗率.     

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。     

上颌第一磨牙MB2根管遗漏与根管治疗失败之间关系的研究

目的：应用根管显微镜,研究上颌第一磨牙根管治疗过程中近中颊根第二根管（MB2）遗漏导致治疗失败病例的比例。方法：在UNIVERSA/FS2012根管显微镜下探查寻找并预备MB2根管,计算检出率的比例。结果：首次根管治疗失败的上颌第一磨牙中,再次治疗时根管显微镜下MB2根管的检出率为81.0%,首次治疗MB2根管的遗漏率为47.1%。结论：传统方法易造成MB2根管遗漏,应用根管显微镜可提高MB2根管的发现率。     

口腔显微镜在上颌第一磨牙根管治疗及再治疗中的应用

目的：探讨显微镜对上颌第一磨牙近中颊根第二根管（second mesiobuccal canals,MB2）的定位探查,以及根管治疗的效果。方法收集患者共88例88颗患牙,在牙科锥形束CT（cone beam computed tomography , CBCT）下确诊MB2存在并接受初次治疗68例,及MB2存在而未发现致根管治疗失败后需再治疗20例。68例患者在CBCT下进一步分析近中颊根根管分型,根据患者的意愿选择不同的治疗方法。试验组34例,显微镜下对MB2进行观察探查并治疗;对照组34例,未用显微镜直视下进行观察探查和治疗。比较2组MB2根管的检出及治疗效果。20例再治疗患者,10例于显微镜下进行再治疗,10例直视下接受常规治疗,比较2组再治疗的效果。结果68颗患牙的CBCT检查结果近中颊根根管以Ⅱ型和Ⅲ型根管为主,其中Ⅱ型53例占77.9%,Ⅲ型15例占22.1%。试验组的MB2检出率为100%,对照组MB2检出率为91.2%,2组差异具有统计学意义（P<0.05）。试验组根管治疗成功率为97.5%,明显高于对照组的79.4%（P<0.05）。2组术后3个月及6个月后试验组疗效构成比明显优于对照组（P<0.05）。显微镜下再治疗成功10例,直视下再治疗成功6例。根管再治疗患者术后3个月及6个月疗效构成比保持不变。结论显微镜对上颌第一磨牙MB2根管的探查及治疗具有一定的临床价值。     

Effect of magnification on locating the MB2 canal in maxillary molars

The purpose of this study was to determine if the surgical operating microscope and/or dental loupes could enhance the practitioner's ability to locate the second mesiobuccal canal (MB2) canal of maxillary molars in an in vivo, clinical setting. The participating endodontists documented 312 cases of root canal therapy on maxillary first and second molars. Participants that used the microscope or dental loupes located the MB2 canal with a frequency of 57.4% and 55.3%, respectively. Those using no magnification located the MB2 canal with a frequency of 18.2%. When no magnification was used, significantly fewer MB2 canals were located based by Chi-square analysis at p < 0.01. There was no significant difference between the use of the microscope and dental loupes in the frequency of locating the MB2 canal. When the maxillary first molars were considered separately, the frequency of MB2 canal detection for the microscope, dental loupes, and no magnification groups was 71.1%, 62.5%, and 17.2%, respectively. The results of this study show that the use of magnification in combined groups leads to a MB2 detection rate approximately three times that of the nonmagnification group and that the use of no magnification results in the location of significantly fewer MB2 canals. Based on these results, more emphasis should be placed on the importance of using magnification for locating the MB2 canal.     

使用手术显微镜对上颌第一磨牙近中颊侧第二根管应用解剖的研究

目的：使用手术显微镜（operating microscope,OM）研究上颌第一磨牙近中颊侧第二根管口（MB2）形态和解剖位置关系，为根管治疗时寻找根管口提供解剖学依据。方法：采用UNIVERSA300/FS2012手术显微镜，观察110个上颌第一磨牙的MB2根管口形态及其发生率。结果：上颌第一磨牙的MB2出现率为38%；根管口的形态为圆形和卵圆形。结论：使用手术显微镜可以有效地发现MB2。     

Detection of the second mesiobuccal canal in mesiobuccal roots of maxillary molar teeth ex vivo

AIM: To assess the effectiveness of magnification and dentine removal (troughing) when locating the second mesiobuccal canal in mesiobuccal roots of maxillary molars. METHODOLOGY: A total of 208 extracted human maxillary molars were examined. After crown and pulp removal, the MB1 and 2 canals in the mesiobuccal root were located in three stages that were performed by two undergraduate dental students. Stage 1: canals were located with an endodontic explorer; stage 2: additional canals in the same teeth were located under magnification with a digital microscope (VH-8000, Keyence, Japan); stage 3: additional canals in the same teeth were located by removing dentine (troughing) from the pulp chamber floor within 3 mm from MB1 canal towards the palatal canal with an Enac ultrasonic tip (ST 21, Osada, Japan). In each group, the canals were prepared with Gates Glidden burs and K-files. The distal and palatal roots were then removed, and Indian ink was injected into the canal system within the mesio-buccal root. The root surfaces were washed with 6% NaOCl, and then rendered transparent to observe canal morphology. The root canal configurations were classified into five categories following the modified Weine's classification. RESULTS: More than one canal in the mesio-buccal root was observed in 48% of specimens. Detection rates of multiple canals were 7, 18 and 42% following stages 1, 2 and 3, respectively. There was a significant difference between the stages for detecting the MB2 canal (P < 0.05, Friedman test). CONCLUSIONS: Both magnification (stage 2) and dentine removal under magnification (stage 3) were effective in detecting the presence of the MB2 canal. However, MB2 canals could not be detected in 13% of the teeth because of canal calcification or branching located more apically.     

Incidence and configuration of canal systems in the mesiobuccal root of maxillary first and second molars

The anatomy of the mesiobuccal (MB) root of 51 maxillary first and 32 maxillary second molars was studied. Initially, an attempt was made to locate all canals using a standard access and hand instruments. A bur was next used carefully to locate any additional second mesiobuccal (mesiolingual (ML)) canals. Finally, after crown removal, the teeth were reduced horizontally in 1-mm increments and examined by microscope. A second ML canal was located in the coronal half of 95.2% of the roots: by hand instruments in 54.2%; bur in 31.3%; and microscope in 9.6%. There were no root perforations when the bur was used as described. The ML canal orifice averaged 1.82 mm lingual to the MB canal orifice. The difference in incidence of ML canals between the first and second molars was not statistically significant. The canal systems were type 1, 4.8%; type 2, 49.4%, and type 3, 45.8%.     

Prevalence of a second canal in the mesiobuccal root of permanent maxillary first molars from an Indonesian population

A sample of 308 extracted human permanent maxillary first molars from an Indonesian population was randomly selected. A rhomboid access cavity was made in all teeth in anticipation of identifying a second mesiobuccal canal (MB2). Ultrasonic tips were used to open the subpulpal groove to locate the second canal in the mesiobuccal root. Dentin was carefully removed from the trifurcation area at the expense of the mesial wall. If a second canal was located, a 0.8 C+ file was inserted into it until the file reached the apex. The prevalence of a second canal in the mesiobuccal root of the permanent maxillary first molar was 68.5% (95% CI: 63.1%-73.4%) in this population. Sections of the mesial root showed that the MB2 was a separate canal in 52.6% of the sample and a joined canal in 47.4%. The mean (SD) distance between MB1 and MB2 was 1.55 (0.66) mm. The data obtained from this study provide theoretical and experimental evidence to aid in the clinical management of the MB2 canal and may increase the success rate for root canal treatment of the maxillary first molar.     

Second mesiobuccal canal detection in maxillary first molars using microscopy and ultrasonics

The aim of this study was to investigate whether the use of operating microscope in combination with ultrasonics increased the rate of second mesiobuccal (MB2) canal detection in permanent maxillary first molar teeth. A hundred extracted human maxillary first molars were assessed. After location of the main canals, the MB2 canal was sought in all teeth first without microscopy, then with the aid of the operating microscope and finally with the combined use of the operating microscope and ultrasonics. With these techniques, the MB2 canal was detected in 62%, 67% and 74% of the teeth, respectively. The combination of the operating microscope and ultrasonics detected significantly more MB2 canals than when no microscopy was utilized (P < 0.05). Sectioning of the roots disclosed the presence of the MB2 canal in 82% of the teeth. Twenty‐nine per cent of the teeth had a separate MB2 canal orifice and separate apical foramina. The results of this study suggested that the combined use of the operating microscope and ultrasonics increased the detection of MB2 canals in maxillary first permanent molars.