下颌管分支的锥形束CT影像学分析

目的 运用锥形束CT（CBCT）分析下颌管分支发生的概率及其类型。方法 选取拍摄CBCT影像的216例（女104 例,男112例）患者为研究对象,对CBCT的下颌管分支影像进行观测并进行分类。结果 216例（432侧）患者中,39例（18.06%）50侧（11.57%）观测到下颌管分支,其中女18例（17.31%）,男21例（18.75%）。下颌管分支分为4类,第Ⅰ类17侧（3.94%）,第Ⅱ类11侧（2.55%）,第Ⅲ类20侧（4.63%）,第Ⅳ类2侧（0.46%）。结论 CBCT对下颌管分支的检出率较高,口腔颌面外科医生在进行下颌手术时应注意下颌管分支这一解剖变异。     

离体下颌前磨牙牙根和根管形态的锥形束CT研究

利用锥形束CT对190个离体下颌前磨牙进行扫描并选择不同方向的断层观察,按Vertucci’s分类法对根管系统进行记录。锥形束CT可以清晰显示其牙根和根管系统形态:下颌第一前磨牙根管系统变异较大,双根管率为22.8%。根管形态分别为Ⅰ型77.14%,Ⅱ型6.67%,Ⅳ型2.86%,Ⅴ型13.33%;下颌第一前磨牙的根面沟发生率较高(47/105),且此类型的下颌第一前磨牙常有双根管;下颌第二前磨牙的根管均为Ⅰ型单根管。     

正常青年人下颌管全长三维走向及下颌骨形态的锥形束CT测量

目的采用锥形束CT（CBCT）分析正常青年人下颌管在下颌骨内的三维位置以及下颌骨的形态特征,为临床下颌骨手术提供解剖学依据。方法 对29例个别正常进行CBCT扫描,用InVivo 5软件对下颌骨进行三维重建,定位标记点,测量下颌骨形态以及下颌管在其内的三维走行。采用SPSS 17.0软件对测量值进行统计分析。结果 下颌管舌侧骨皮质厚度明显较颊侧骨皮质薄。下颌管到颊侧骨皮质的距离从近中到远中逐渐增加,到舌侧骨皮质、牙槽嵴顶的距离从近中到远中逐渐减小,到下颌下缘的距离在第一磨牙处最小,第二前磨牙处最大。下颌体截面高度、宽度、皮质骨厚度左右侧无统计学差异,从中线至远中,下颌体截面高度、舌侧下1/3皮质骨厚度逐渐减小,上截面宽度、唇/颊侧上1/3皮质骨厚度逐渐增大。部分测量项目性别间有统计学差异。结论下颌管入下颌孔后渐渐远离舌侧而向颊侧靠近,然后又逐渐远离偏向舌侧,但其总体走行还是靠近舌侧。男性下颌骨较女性更坚厚。CBCT能精确地显示下颌神经管的走行及其与周边结构的关系。     

锥形束计算机体层摄影术观察下牙槽神经管形态及其临床意义

目的 应用锥形束计算机体层摄影术（CBCT）观测并分析下牙槽神经管在下颌骨内的走行特点,探讨其分布规律,为临床手术提供解剖学依据.方法 采用单纯随机抽样法选取具备下颌后部CBCT 扫描数据的患者60 例,应用CBCT 自带的KaVo eXam Vision 软件测量颏孔区、前磨牙区、磨牙区下牙槽神经管与牙槽嵴顶、下颌骨颊舌侧骨板及下缘的平均距离,对各组测量项目进行成组t 检验比较,并观察其走行特点.结果 下牙槽神经管距下颌下缘小于距牙槽嵴顶的距离,在第二磨牙区距离下颌骨下缘最近;颏孔区至第一磨牙区间,下牙槽神经管距颊侧骨板距离小于距舌侧骨板距离,自第二磨牙后,下牙槽神经管距颊侧骨板距离则大于距舌侧骨板距离;性别及左、右侧下牙槽神经管距离差异无统计学意义（t＝2.437,P ＞ 0.05）.结论 CBCT 扫描有利于更好了解下牙槽神经管的走行及结构特异性,对牙槽外科及种植外科手术方案的制定具有一定临床指导意义.     

锥形束CT与曲面断层在诊断下颌骨骨折中的比较研究

目的对比研究锥形束CT与曲面断层对下颌骨骨折的诊断特点及差异。方法收集2010年4月至2010年10月共27例因颌面部外伤行锥形束CT和曲面断层检查的患者的临床资料,比较两种方法对下颌骨不同部位骨折的诊断率。结果锥形束CT在下颌骨各部位的骨折诊断中均能明确观察骨折线及断端移位情况,而曲面断层存在漏诊现象,漏诊率为27.5%（11/40）,特别是髁突及颏部骨折,漏诊率分别为35.3%和27.3%。结论曲面断层检查存在漏诊的可能,特别是髁突或颏部骨折时,漏诊率更高。建议对下颌骨骨折应结合锥形束CT检查,以避免漏诊。同时,锥形束CT三维重建在帮助医生制定手术计划方面有很大优势和广泛应用前景。     

Anatomic relationship between impacted third mandibular molar and the mandibular canal as the risk factor of inferior alveolar nerve injury

Our aim was to explore the relation between the site of the mandibular canal and neurosensory impairment after extraction of impacted mandibular third molars.     

下颌前磨牙牙根形态和根管系统的锥形束CT研究

目的采用锥形束CT(Cone-beam computed tomography,CBCT)研究下颌前磨牙牙根及根管系统解剖形态特征。方法回顾148例患者288颗下颌第一前磨牙和218颗下颌第二前磨牙的CBCT影像,分析牙根和根管系统形态,采用Vertucci等提出的分类法对根管构型进行分类。结果 288颗下颌第一前磨牙单根牙285颗,双根牙2颗。三根牙1颗;根管Ⅰ型占77.78%,Ⅱ型0.34%,Ⅲ型2.08%,Ⅳ型0.69%,Ⅴ型14.58%,Ⅶ型1.04%,Ⅹ型0.69%,C型2.78%。218颗下颌第二前磨牙全部为单根;根管Ⅰ型占98.17%,Ⅴ型占1.83%。结论下颌前磨牙大多数是单根单根管。下颌第一前磨牙根管系统具有较大的变异性。下颌第一前磨牙多根管类型主要是Ⅴ型,C型根管的检出率也较高。而下颌第二前磨牙多根管的发生率远低于下颌第一前磨牙。多根管的分歧发生在根中或根尖1/3处。CBCT可用于下颌前磨牙复杂根管形态的评价。     

Evaluation of mandibular transverse widths in patients affected by unilateral and bilateral cleft lip and palate using cone beam computed tomography

Objective:To evaluate the mandibular dental, alveolar, and skeletal transversal widths in patients affected by unilateral (UCLP) and bilateral (BCLP) cleft lip and palate and to compare the findings with a well-matched normal occlusion sample using cone beam computed tomography images.Materials and Methods:The study sample consisted of 75 patients divided into three groups: the UCLP (29 patients; mean age: 15.40 ± 3.22 years), BCLP (18 patients; mean age: 15.54 ± 3.72 years), and normal occlusion (28 patients; mean age: 15.82 ± 2.11 years) groups. Mandibular dental (intercanine and -molar), alveolar (intercanine and -molar), and skeletal (bigonial width) transversal measurements were performed three-dimensionally and analyzed using the one-way variance analysis and post hoc Tukey tests.Results:Patients affected by UCLP and BCLP had statistically significantly lower intercanine alveolar widths (P < .05 and P < .001, respectively) and larger intermolar (P < .001 and P < .05, respectively) and intermolar alveolar widths (P < .001) compared with the normal occlusion group. Furthermore, the patients affected by UCLP and BCLP had similar mandibular dental, alveolar, and skeletal transversal widths (P > .05).Conclusion:The UCLP and BCLP groups showed statistically significantly smaller values for intercanine alveolar widths and larger values for intermolar dental and alveolar widths compared with the normal occlusion group. This shows the importance of using individualized archwires according to the pretreatment arch widths of the patients affected by UCLP and/or BCLP.     

下颌切牙根管解剖特点的锥形束CT影像学研究

目的采用锥形束CT研究下颌切牙根管解剖特点,及其与性别、年龄、牙位的关系。方法使用锥形束CT观察316例共1148颗下颌切牙,获得其断层图像后进行三维重建,通过计算机图像观察其根管数目及根管类型。记录被检查者的性别、年龄和牙位。计算下颌切牙双根管检出率,统计根管类型,分析根管解剖特点与性别、年龄、牙位的关系。结果下颌切牙双根管检出率为27．5％,其双根管类型以Vertucci分类的Ⅲ型最多,占14．1％。双根管在各年龄段间的分布差异有统计学意义（P〈0．05）,20～29岁和30～39岁两个年龄段的双根管检出率较高,分别为36．8％和36．5％。下颌切牙双根管的检出率女性高于男性。侧切牙双根管的检出率高于中切牙,结论下颌切牙双根管检出率较高,锥形束CT在诊断双根管方面具有重要作用。     

Application of cone beam computed tomography in facial imaging science

Facial imaging is used to study the facial shapeand its developmental changes over time.This isimportant to diagnose acquired malformations,to studynormal and abnormal growth and to differentiatebetween the results of treatment and normal growth,and to validate facial recognition.The two mainmethods to study and record facial imaging are bymeans of cephalometry and anthropometry[1].Cephalometrics is the scientific study of themeasurements of the head’s     

锥形束CT灰度值与密度相关性的研究

目的:研究锥形束CT灰度值与体外已知密度参考模型的相关性,并分析锥形束CT不同拍摄条件对密度测量值的影响.方法:将已知密度分别为:1.0、1.5、2.0、2.5 g/cm3的小球固定在模型上,该模型分别放置在直径约为14 cm和16 cm盛满水的圆柱形玻璃烧杯内,并在不同拍摄条件下进行锥形束CT扫描测得小球灰度值.结果...     

The use of cone beam computed tomography in the management of isolated orbital floor fractures

Isolated fractures of the orbital floor are diagnosed by a combination of clinical and radiographic findings. Computed tomography is considered the imaging method of choice. We describe the use of cone beam computed tomography for use in isolated fractures of the orbital floor. This shows defects in the orbital floor but with a lower dose of radiation than conventional computed tomography.     

A significant incidental finding on cone beam computed tomography: multiple myeloma

Cone beam computed tomography is widely used in dentistry. Incidental findings are common, with many requiring intervention or monitoring. We present a rare case of previously undiagnosed, asymptomatic multiple myeloma first identified incidentally on cone beam computed tomography and panoramic radiography. This case highlights the diverse range of lesions that may appear on cone beam computed tomography and the importance of radiologic interpretation.     

Comparison of root resorption between self-ligating and conventional preadjusted brackets using cone beam computed tomography

Objective:To compare the magnitude of external apical root resorption (EARR) of incisors in patients undergoing the initial phase of orthodontic treatment with two sets of brackets.Materials and Methods:According to the results of the power analysis for sample size calculation, 19 Angle Class I patients (anterior crowding: 3 to 5 mm; mean age: 20.6 years) were included in the study and randomly divided into two groups: group I (n  =  11, self-ligating brackets) and group II (n  =  8, conventional preadjusted brackets). The degree of EARR was detected in 152 upper and lower incisors by using cone-beam computed tomography (CBCT) scans and a three-dimensional program (Dolphin 11.5, Dolphin Imaging & Management Solutions, Chatsworth, Calif) with 25% level of sensitivity. The CBCT scans were obtained before (T1) and 6 months after initiation of treatment (T2). Differences between and within groups were analyzed by nonpaired and paired t-test, respectively, with 5% significance level.Results:Significant differences were found for both groups between T1 and T2. However, no differences in the degree of EARR were detected between the groups studied.Conclusions:Although EARR has occurred in all teeth evaluated, the bracket design (self-ligating or conventional) did not demonstrate any influence on the results observed.     

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目的利用锥形柬计算机断层扫描（CBCT）研究上颌第一磨牙近中颊根第二根管（MB2）发生率、根管解剖形态以及根管口位置分布。方法随机选取2011-2013年航天中心医院口腔科20～30岁患者CBCT影像160张（男80张、女80张）。平行近中颊根长轴平面观察其根管形态,并按照Vertucci分类统计。水平面观察根管口的位置,记录MB、MB2及腭根根管口间距离以及MB、MB2根管口分别到腭根根管口连线夹角,并比较不同性别间差异。结果本研究观察了279颗上颌第一磨牙,其中存在MB2牙齿233颗,检出率为83．5％,不同性别间差异无统计学意义（P〉0．05）。不同类型的根管出现概率不同,各类型出现率男女间无差异。MB与MB2根管口间距男性为（2．195±0．504）mm,女性为（1．966±0．419）mm,差异有统计学意义（P〈0．05）。结论上颌第一磨牙MB2发生率高,不同类型MB2发生概率不同,男性与女性之间无差异。MB与MB2根管口间距在两性之间存在统计学差异。     

CBCT法研究上颌第一磨牙根管形态

目的：探讨应用锥形束CT研究上颌第一磨牙牙根及根管形态的价值。方法选取70例患者83颗上颌第一磨牙的锥形束CT（cone beam computed tomogaphy,CBCT）影像,分析其牙根数目、根管数目及根管系统的解剖结构。参照Vertucci分类法对根管形态进行分类,统计近中颊根第二根管（the seconal mesiobuual canal, MB2）率。结果83颗上颌第一磨牙均为3个独立牙根,其中MB2的发生率为38.6%,近中颊根根管VertucciⅠ型（1?1）、Ⅳ型（2?2型）、Ⅱ型（2?1）、Ⅲ型（1?2?1）所占百分比分别为61.4%、18.1%、15.7%和4.8%。结论上颌第一磨牙根管系统复杂,CBCT影像可反映真实根管形态,为根管治疗提供参考。     

根管封闭剂和锥形束CT拍摄参数对牙根纵裂诊断的影响

目的 研究根管封闭剂和锥形束CT(CBCT)拍摄参数对牙根纵裂(vertical root fractures,VRF)诊断的影响。方法 收集人前磨牙40颗,去冠,随机均分为4组:iRoot SP、AH Plus、载银锌介孔钙硅纳米粒子(Ag-Zn-MCSNs)和对照组。根管充填后制备VRF模型,然后将牙根置入人上颌前磨牙牙槽窝内,拍摄CBCT,视野(field of view,FOV)和体素分别为:12 cm×8 cm、0.30 mm;12 cm×8 cm、0.15 mm;8 cm×8 cm、0.15 mm;8 cm×8 cm、0.30 mm。由2名观察者对CBCT图像进行判读。结果 各实验组之间的准确性均无统计学差异(P＞0.05)。医师正确诊断根纵裂的部位均是在轴面冠1/3区。结论 不同根管封闭剂和CBCT拍摄参数诊断VRF的准确性无显著影响,建议应用CBCT诊断根充牙齿的VRF时,在满足诊断需求的前提下,选择较小FOV及较大的体素,以尽量降低辐射剂量。     

Apical root resorption due to orthodontic treatment detected by cone beam computed tomography

Objective:To determine the frequency of apical root resorption (ARR) due to orthodontic treatment using cone beam computed tomography (CBCT) in a sample of 1256 roots from 30 patients.Materials and Methods:All patients had Class I malocclusion with crowding. Of the 30 patients evaluated, 11 were boys and 19 were girls; their mean age was 13 years (11 to 16 years). Orthodontic treatment followed the nonextraction treatment. CBCT images were obtained before and after orthodontic treatment, and ARR was determined using Axial Guided Navigation of CBCT images.Results:All patients had ARR. No statistically significant association was found between resorption frequency, gender, and age. ARR was detected using CBCT in 46% of all roots that underwent orthodontic treatment.Conclusions:CBCT was effective for detecting in vivo even minimal degrees of ARR due to orthodontic treatment and allowed three-dimensional evaluation of dental roots and visualization of palatine roots of maxillary molars. The highest frequencies and the most significant ARR occurred in incisors and distal roots of first maxillary and mandibular molars.