805颗上下颌第三磨牙牙根及根管形态的观测

目的检测上下颌第三磨牙牙根及根管形态，为人类学提供资料。方法采用离体牙经透明牙标本制备，用XXT-3A连续变倍体视显微镜检测上下颌第三磨牙根管形态。结果805颗第三磨牙牙根形态可分为六型，上颌第三磨牙牙根形态Ⅲ型占57．5％。下颌第三磨牙牙根形态Ⅳ占52．88％。其主根管形态可分六型，Ⅰ型占62．12％。结论上下颌第三磨牙牙根形态，根管类型具有复杂性。     

上下颌前牙根根管系统解剖及临床意义

目的了解上下颌前牙牙根数目,根管类型,为临床前牙根管充填提供理论依据。方法采用离体牙经透明牙标本制备,用XXT-3A连续变倍体视显微镜检测上下颌前牙根管系统。结果1973颗前牙1975支牙根的主根管类型分为六型,I型上颌前牙占100%、下颌前牙占74.97%;侧副根管分四种:根管侧支检出率17.97%,管间吻合检出率0.81%,根尖分歧检出率4.61%,根尖分叉7.39%。结论上下颌前牙根管形态及根管系统具有规律性和多变性。     

300个下颌第一恒磨牙根管类型的透明牙观测

目的 了解下颌第一恒磨牙根管的类型，为提高根管预备的效果提供解剖学依据。方法 采用透明牙技术用连续变倍体视显微镜对该牙根管类型进行观测。结果 300个离体牙中，共检出八种根管类型。其中1—1—1型、2—2—1型、2—2—2型最多，占91．4％。远中舌根的发生率为24．7％；双根管口率：近中根为78．3％，远中根(不含远中舌根，下同)为19．3％；双根管率：近中根为88．3％，远中根为23．3％；双根尖孔率：近中根为56．7％，远中根8．3％，单根管口而有双根尖孔，近中为6．7％，远中为3．3％。结论 下颌第一恒磨牙根管的类型复杂，充分了解其根管解剖对提高根管预备效果、减少根臂遗漏有重要意义。     

下颌前牙根根管系统解剖及临床意义

目的了解下颌前牙牙根数目,根管类型,及侧副根管出现率,为提高下颌前牙根管治疗提供解剖学依据。方法采用开髓真空负压吸入美兰染色的透明牙标本,用XXT-3A连续变倍体视显微镜检侧下颌前牙根管系统。结果945颗下颌前牙947支牙根的主根管类型分为六型,I型占74.97%,Ⅱ~Ⅵ型占25.03%;侧副根管分四种,根管侧支检出率11.51%,管间吻合检出率1.69%,根尖分歧检出率4.22%,根尖分叉6.02%。结论下颌前牙根管系统具有规律性、多变性。     

下颌第一前磨牙根管系统和根尖孔解剖及临床意义

采用牙髓透明法对 347颗下颌第一前磨牙根管系统的数目和形态进行观察。下颌第一前磨牙根管可分为Ⅰ、Ⅱ、Ⅲ、Ⅳ型。其中Ⅰ型 (单根单管型 )占 83 86 % ,Ⅱ型 (单根双管型 )占 4 6 1% ,Ⅲ型 (单双管混合型 )占 11 2 4 % ,Ⅳ型 (双根双管型 )占 0 2 9%。应用XTT— 3A连续变倍体视显微镜对 347颗下颌第一前磨牙的根管系统形态进行观察 ,根尖分歧出现率 15 6 3% ,根尖分叉出现率 2 4 3% ,根管侧支出现率 1 0 8%。并对 347颗下颌第一前磨牙的根尖孔与根尖顶的位置关系进行观察 ,根尖孔位于根尖顶者占 88 14 % ,位于旁侧者占 11 86 %。并就上述内容的临床意义进行了讨论。     

层递探查法探查下颌第一恒磨牙近中中央根管成功率的体外评价

目的探讨体外三阶段层递探查法探查离体下颌第一恒磨牙近中中央根管(MMC)的成功率,并研究下颌第一恒磨牙MMC的解剖形态学特征。方法收集近期拔除的下颌第一恒磨牙60颗,采用肉眼直视下探针探查、显微镜辅助探查、显微镜辅助超声预备三阶段层递探查法探查下颌第一恒磨牙MMC,最终对未发现MMC的离体牙采用透明牙染色法,以此为对照评价上述三阶段探查MMC的成功率;分析MMC的形态分类以及在各年龄段中的分布情况。结果层递探查法各阶段探查离体牙MMC的发现率分别为5.3%(3颗)、8.8%(5颗)、21.1%(12颗);经透明牙染色法确认后,有1颗离体牙的MMC被遗漏;体外三阶段各自的探查成功率分别为23.1%、38.5%、92.3%;第一、二阶段MMC发现率比较差异无统计学意义(P>0.05),第三阶段与第一、二阶段比较,差异均有统计学意义(P<0.05);MMC的根管解剖学分型多为融合型(3-2型、3-1型);MMC在21~40岁组中的发现率最高(33.3%)。结论体外三阶段层递探查法能有效提高下颌第一恒磨牙中MMC的发现率,在显微镜辅助超声预备下探查MMC的成功率明显较高;MMC的解剖形态相对复杂,与近中主根管间的联系紧密,且随着年龄的增长,MMC的发现率逐渐降低。     

下颌管的三维重建及临床意义

目的　为下颌牙种植术等临床口腔外科提供解剖学基础。 方法　选取全牙志愿者20名,在螺旋CT机以眶耳线(OML)为基线连续扫描,采用ADW 4.2重建软件的曲面重组技术(CPR)重建下颌管,观察下颌管的位置、构造和测量下颌后牙牙根至下颌管上壁的距离;在Amira三维重建软件下重建下颌骨及下颌管的可视化模型,观察透明下颌骨内下颌管的走行及其与下颌后牙的关系。 结果　下颌管壁由一薄层骨密质构成,自磨牙牙根尖舌侧和前磨牙牙根尖颊侧的下方走行;透明下颌骨内的下颌管可清晰显示其位置、形态及走行,下颌管与下颌体下缘、牙槽嵴及内、外侧骨板的距离。下颌后牙牙根至下颌管的距离以第2磨牙最近,由近及远依次为第2磨牙、第1磨牙、第3磨牙、第2前磨牙和第1前磨牙;下颌磨牙的远中根至下颌管的距离均较近中根近。第1前磨牙、第2前磨牙、第1磨牙、第2磨牙、第3磨牙牙根至下颌管上壁的最短距离分别为(8.38±1.04) mm(左)和(8.44±1.05) mm(右)、(7.51±0.85) mm、(3.40±　0.65) mm、(2.93±0.61) mm、(3.92±0.63) mm(左)和(3.97±0.63) mm(右)。 结论　下颌管的三维重建对选择适宜长度的牙种植体,避免牙种植体损伤下牙槽神经等具有重要意义。     

下颌管的应用解剖及临床意义

目的:为下颌牙种植术等临床口腔外科提供解剖学基础.方法:选取下颌骨标本10例、新鲜下颌骨标本10例和成人全牙下颌骨标本20例,分别暴露出下颌管截面、下牙槽神经血管束和下颌管与下颌后牙牙根.观察下颌管的形态、走行和下牙槽神经、血管的排列关系,用游标卡尺测量下颌后牙牙根尖至下颌管上壁的距离.结果:下颌管呈椭圆形,自磨牙牙根尖舌侧和前磨牙牙根尖颊侧的下方走行;下颌管内的下牙槽血管位于下牙槽神经上方.下颌后牙牙根至下颌管的距离以第2磨牙最近,由近及远依次为第2磨牙、第1磨牙、第3磨牙、第2前磨牙和第1前磨牙;下颌磨牙的远中根至下颌管的距离均较近中根近.第1前磨牙、第2前磨牙、第1磨牙、第2磨牙、第3磨牙牙根至下颌管上壁的最短距离分别为(8.19±0.87) mm(左)和(8.29±0.88) mm(右)、(7.38±0.85) mm、(3.30±0.66) mm、(2.98±0.77) mm(左)和(2.92±0.75) mm(右)、(3.82±0.63) mm(左)和(3.86±0.64) mm(右).结论:下颌管的应用解剖对选择适宜长度的牙种植体,避免牙种植体损伤下牙槽神经等具有重要意义.     

上颌第一前磨牙X线法髓腔物理量

目的:探讨上颌第1前磨牙X线片法髓腔物理量方面的数据.方法:用X线平行投照法拍摄实体牙颊舌向和近远中向X线片牙影像,根据本研究对髓腔根管定的分型标准对根管进行分型.用电脑配套的柯达成像系统测量X线片牙的髓高、髓宽、根中颊径、根中舌径、根尖颊径和根尖舌径.用SPSS17.0软件统计处理X线片牙的髓腔物理量值.结果:100颗上颌第1前磨牙中X线片牙根管有6种类型,Ⅰ-1-1型占33％,Ⅰ-2-2型占17％,Ⅰ-2-1型占13％,Ⅰ-1-2型占4％,Ⅰ-2-1-2型占3％,Ⅱ-2-2型占30％.X线片牙的测量值(mm)显示,髓高3.09±1.18,髓宽3.88±0.61,根中颊径1.76±1.18,根中舌径0.59±0.34,根尖颊径0.79±0.39,根尖舌径0.35±0.28.髓腔物理量各测值差异均存在统计学意义.结论:上述结果说明,湖北地区上颌第1前磨牙根管类型主要是Ⅰ-1-1型,Ⅰ-2-2型,Ⅱ-2-2型.X线片牙物理量测值经相关及回归分析,如果有相关性的配对项,可用回归方程中的自变量值(X)来推测因变量的值(Y),为口腔临床实践提供髓腔物理量方面的未知数据.     

下颌管与下颌后牙的位置关系及临床意义

目的: 为下颌牙种植术等临床口腔外科提供解剖学基础。方法：选取新鲜下颌骨标本10例、成人全牙下颌骨标本18例和20名全牙志愿者,分别暴露出下牙槽神经血管束、下颌管与下颌后牙牙根和CT连续扫描后进行三维重建。观察下牙槽神经、血管的排列关系,用游标卡尺和CT三维重建工作站分别测量下颌后牙牙根至下颌管上壁的距离。结果：下颌管自牙槽窝下方走行,其舌侧骨板较厚;下颌管内的下牙槽血管位于下牙槽神经上方。下颌磨牙的远中根至下颌管的距离均较近中根近。在标本及影像上的第1前磨牙、第2前磨牙、第1磨牙、第2磨牙、第3磨牙牙根至下颌管上壁的距离分别为(8.36±2.34)　mm和(8.42±2.42)mm、(7.36±2.21)mm和(7.52±2.18)mm、(3.22±1.40)mm和(3.36±1.85)mm、(2.96±1.54)mm和(2.84±1.55)mm、(3.64±1.72)mm和(3.88±1.76)mm。结论：（1）下颌后牙至下颌管的距离以第2磨牙最近,由近及远依次为第2磨牙、第1磨牙、第3磨牙、第2前磨牙和第1前磨牙。（2）对选择适宜长度的牙种植体,避免牙种植体损伤下牙槽神经等具有重要意义。     

Root Canal Morphology of Chalcolithic and Early Bronze Age Human Populations of El Mirador Cave (Sierra de Atapuerca,Spain)

This study provides a morphological characterization of the inner anatomy of the root canals of permanent first and second molars in Chalcolithic and early Bronze Age human fossils using cone‐beam computed tomography. The general evolutionary trend in present‐day human dentition is related to morphological simplification. As little is known about when this trend appeared in Homo sapiens populations, the aim of this work is to test the presence of modern radicular morphology 4,400 years ago. Fifty‐four permanent first and second maxillary and mandibular molars of 17 individuals were included in the study. All maxillary first and second molars showed three separate roots. Almost all the lower molars analyzed (100% of first molars and 75% of second molars) had two separate roots. More differences in the canal system configuration were documented in the maxillary mesiobuccal roots than in the palatal or distobuccal roots. The most variable tooth in root and canal configuration is the maxillary second molar. It should be pointed out that 12.5% of the teeth analyzed showed a C‐shaped root configuration. Anat Rec, 297:2342–2348, 2014. © 2014 Wiley Periodicals, Inc.     

The morphology of maxillary first and second molars analyzed by cone-beam computed tomography in a polish population

Background

The success of endodontic treatment is greatly affected by the location of the root canals. The purpose of this study was to evaluate the root and canal morphology of permanent maxillary first and second molars in a Polish population using cone-beam computed tomography scanning.

Methods

Cone-beam computed tomography (CBCT) scans of maxillary first and second molars the maxilla were examined. The number of roots and root canals, and the frequency of additional canals (MB2) in the mesiobuccal root canals were determined. The results were subjected to statistical analysis using the chi-square test or the chi-square test with Yates’ correction.

Results

A total of 112 CBCT images of maxillary first (n?=?185) and second molars (n?=?207) from 112 patients were analyzed. All the maxillary first molars had three roots (100%). The majority of maxillary second molars had three roots (91.8%), 5.8% had two roots and 2.4% had one root. A statistically significant difference was observed between the numbers of roots in the maxillary first and second molars (p?<?0.01). A statistically significant difference was also found in the distribution of the number of canals in the maxillary first and second molars (p?<?0.001). The majority of maxillary first molars had four root canals (59.5%), while 40.5% had three root canals. Most maxillary second molars had three root canals (70%). Additional canals (MB2) in the mesiobuccal roots were detected significantly more frequently in the maxillary first molars than the second molars (p?=?0.000) and more frequently in men than in women (p?<?0.05). A higher prevalence of two canals in the mesiobuccal roots in maxillary second molars occurred in patients aged between 31 and 40 years than in patients aged between 21 and 30 years. In the maxillary first molars, the prevalence of the MB2 canal in the mesiobuccal root was almost equally distributed in the two age groups (21–30 and 31–40 years).

Conclusion

Within the limitations of this study, it can be concluded that there are differences in the number and configuration of roots and root canals between maxillary first and second molars in the studied patients of a Polish population.

     

Use of CBCT to investigate the root canal morphology of mandibular incisors

Purpose

To investigate the root canal morphology of mandibular incisors using cone-beam computed tomography (CBCT).

Materials and methods

A total of 353 patients with 1,412 healthy, well-developed mandibular incisors were enrolled. Radiographic examination by CBCT was conducted as part of their routine examination, diagnosis and treatment planning. The following observations were made using CBCT: (1) the number of roots; (2) the number of canals; (3) canal configuration according to Vertucci’s classification; (4) the position of root canal bifurcations.

Results

Two canals were found in 10.9 % of mandibular central incisors, 25.5 % of lateral incisors and in 18.2 % of all the 1,412 mandibular incisors. Significantly, more lateral incisors possessed two canals than central incisors (p < 0.05). Of the teeth with two canals, type III incisors were the most prevalent, followed by types II, IV and V. Furthermore, 37.7 % of teeth were found to have root canal bifurcations that were at or near to the cortical-middle third junction regions of the roots.

Conclusion

Routine mode CBCT imaging was clinically useful for detection of two canals and determines the position of root canal bifurcations in mandibular incisors.     

Anatomical evaluation of the root canal diameter and root thickness on the apical third of mesial roots of molars

The purpose was to determine the diameter of the main root canal and wall thickness in the apical dentin in mesial roots of maxillary and mandibular molars. Forty mesiobuccal and mesial root specimens were sectioned horizontally at 1, 2 and 3 mm from the apex, and measured at each top surface by using optical microscopy to an accuracy of ×20 magnification. The anatomical parameters were established as the following points of reference: AB, two points connected by a line from the outer edge of the mesial wall to the outer edge of the distal one through the center of the root canal to measure the thickness of the root and mesiodistal diameter of the root canal (CD). A second line (EF) was designed to evaluate the diameter of the root canal in the buccolingual direction. All data were summarized, and values were assessed statistically by ANOVA and Bonferroni multiple comparisons. The buccolingual (BL) root canal diameters at 1, 2 and 3 mm in the mandibular and maxillary molars were greater than in the mesiodistal (MD), showing statistically significant differences (p < 0.05). The MD root thicknesses at 1, 2 and 3 mm in mandibular and maxillary molars were statistically significant (p < 0.05). The lowest value to 1 mm from the apex in the mandibular molars was 1.219 mm and the highest at 3 mm from the root apex in maxillary molars was 1.741 mm. The BL diameters in maxillary and mandibular molars were higher than the MD diameter. The thickness (MD) of maxillary and mandibular molars decreased as a function of apical proximity.     

Correlation of mandibular impacted tooth and bone morphology determined by cone beam computed topography on a premise of third molar operation

Purpose

To determine the width and morphology of the mandible in the impacted third molar region, and to identify the location of the mandibular canal prior to planning impacted third molar operations.

Methods

Cone beam computed tomography (CBCT) data of 87 mandibular third molars from 62 Japanese patients were analyzed in this study. The width of the lingual cortical bone and apex-canal distance were measured from cross-sectional images in which the cortical bone was thinnest at the lingual side in the third molar region. Images were used for measuring the space (distance between the inner border of the lingual cortical bone and outer surface of the third molar root), apex-canal distance (distance from the root of the third molar tooth to the superior border of the inferior alveolar canal) and the cortical bone (width between the inner and outer borders of the lingual cortical bone).

Results

The means of the space, apex-canal distance and lingual cortical width were 0.31, 1.99, and 0.68 mm, respectively. Impacted third molar teeth (types A–C) were observed at the following frequencies: type A (angular) 37 %; type B (horizontal), 42 %; type C (vertical), 21 %. The morphology of the mandible at the third molar region (types D–F) was observed as: type D (round), 49 %; type E (lingual extended), 18 %; and type F (lingual concave), 32 %.

Conclusions

The width and morphology of the mandible with impacted teeth and the location of the mandibular canal at the third molar region could be clearly determined using cross-sectional CBCT images.     

胸腰骶段脊神经根鞘结构的解剖学和组织学研究

目的　明确胸腰骶部不同节段脊神经根鞘的解剖学和组织学结构及其分布特点,探讨其临床意义。 方法　取7例成人脊柱标本,解剖观察胸腰骶部不同节段神经根鞘的硬脊膜囊开口方式,并制成组织切片后显微镜下观察神经根鞘的结构。 结果　胸腰段神经根鞘存在单孔和双孔两种硬脊膜囊开口方式,而骶段神经根鞘只存在单孔开口方式;单孔根鞘又根据前、后根之间有无双层袖套结构分为Ⅰ型和Ⅱ型。较之神经根其他部位,神经节处硬脊膜袖套的胶原纤维层少且结合疏松。腰4/5和骶1~5节段神经节处的硬脊膜袖套的厚度比其他节段更薄（F=37.31,P<0.01）。神经根袖套下腔隙终止于神经节。 结论　Ⅰ型和Ⅱ型神经根鞘在各节段的分布规律,解释了腰骶部神经根受压时多表现为感觉和运动功能同时受累的现象;而神经节处的硬脊膜袖套在下腰骶节段最薄的特点,也和腰腿痛高发的现象相关系。脊神经节是脊神经根开始转化为脊神经的标志。     

Risk assessment of inferior alveolar neurovascular bundle by multidetector computed tomography in extractions of third molars

Purpose

This study aimed to assess the reliability of multidetector computed tomography (MDCT) in determining the surgical risk of the inferior alveolar neurovascular bundle in extractions of third molars.

Methods

The sample comprised thirty-three individuals (63 third molars) who underwent preoperative evaluation by MDCT before extraction of impacted mandibular third molars. MDCT was used to determine the relationship between the roots of the third molars and the mandibular canal, and the course of the mandibular canal. Inferior alveolar nerve (IAN) exposure and the presence of hemorrhage were analyzed after removal of the teeth. IAN neurosensory deficit was recorded after 7?days. Clinical and MDCT findings were compared using Fisher’s exact test (P?Results There was a statistically significant association between IAN exposure and the tomographic relationship between the roots of third molars and the mandibular canal (P?=?0.015). Conventionally, all cases of IAN neurosensory deficit and hemorrhage occurred when the roots of the third molar presented in an at-risk relationship with the mandibular canal, however, this association was not statistically significant (P?>?0.05). A statistically significant association was found between the lingual course of the mandibular canal and IAN exposure (P?=?0.03).

Conclusions

MDCT is an effective tool for determination of the surgical risk to the inferior alveolar neurovascular bundle in extraction of mandibular third molars.     

Evaluation of the relationship between the maxillary posterior teeth and the sinus floor using cone-beam computed tomography

Aim

The aim of this study was to evaluate the relationship between each root of maxillary premolars and molars and the maxillary sinus floor according to sex, sinus position, and age by decade in a Turkish population by using cone-beam computed tomography (CBCT) scanning.

Methodology

We evaluated a database of 5,166 (2,680 maxillary premolars and 2,486 maxillary molars) CBCT scans obtained from 849 patients. The vertical relationship between each root of the molar and premolar teeth to the sinus floor was classified into three types: type 1, the roots penetrated into the sinus floor; type 2, the roots contacted the sinus floor; and type 3, the roots extended below the sinus floor.

Results

The results of the classification of each root in relationship to the sinus floor were as follows: type 3 occurred most frequently in the first (92.4 %) and second (71.6 %) premolar teeth, type 1 (34.2 %) occurred most frequently in the palatinal roots of the first molar teeth, type 3 occurred most frequently in the mesiobuccal (39.9 %) and distobuccal (39.7 %) roots of the first molar teeth, and type 2 (36.7 %) occurred most frequently in the mesiobuccal roots of the second molar teeth. No significant differences were found between the left and right sides, but several differences were found between males and females. The relationship between the posterior teeth and the sinus floor differed according to the age decade interval (p < 0.05).

Conclusions

The maxillary first premolars have no relationship with the maxillary sinus floor, but the maxillary second molars are closer to the sinus floor. Also the second decade and males were most susceptible to undesirable results.