显微CT法研究中国人下颌切牙根管系统解剖形态

目的:使用显微CT扫描技术研究中国人离体下颌切牙根管系统解剖形态。方法:收集108颗中国人下颌切牙,使用显微CT进行扫描后构建根管系统三维可视化模型。对主根管形态进行分型,记录第二根管分出位置,分支根管的发生率和位置。结果:下颌切牙根管最常见的形态为VertucciⅠ型和Ⅲ型,发生率分别为78.70%和14.81%,分支根管发生率为24.07%。第二根管发出位置在釉质牙骨质界根方(6.07±3.42) mm。结论:下颌切牙根管系统解剖形态复杂,了解其主根管及分支根管的发生规律对于提高根管治疗成功率具有重要意义。     

牙颌CT对上颌磨牙近中颊侧第二根管的影像学研究

目的：利用牙颌CT（PROMAX3D）研究活体上颌磨牙近中颊侧第二根管（MB2）口、髓腔形态及其解剖位置关系影像,为临床根管治疗提供可靠的影像学依据。方法：对上颌磨牙根管治疗的患者,使用牙颌CT进行扫描,感兴趣区重建完成之后在颊舌向、水平位以及3D影像上针对上颌磨牙根管数目、牙髓形态影像分析研究。结果：牙颌CT能够在水平位和3D影像上清晰地显示上颌磨牙近中颊侧第二根管的数目、根管口的形态,在颊舌向影像上清楚地显示MB2髓腔的形态及走向。结论：牙颌CT利用不同方向的影像,真实地显示了上颌磨牙近中颊侧第二根管口的形态和髓腔的走向,为临床根管治疗提供可靠的影像学依据,有效地指导了临床医师的治疗工作。     

数字化根管定位导板应用于完全钙化根管的临床报道1例

髓腔完全钙化的牙齿需要行根管治疗时,精确定位并疏通钙化根管、避免侧穿是困扰临床医生的一大难题.随着锥形束CT、口内扫描和3D打印技术的逐步成熟,数字化根管定位导板技术可以通过计算机辅助设计定位到狭窄的根管通路,最大程度地保存牙体组织,提高根管治疗的安全性和成功率,该文报道1例将数字化根管定位导板应用于髓腔完全钙化的前牙...     

光学相干断层成像技术对牙本质成像及其厚度定量测量的研究

目的:研究光学相干断层成像(OCT)技术对牙本质的成像及量化测定能力。方法:磨除20颗下颌中切牙舌侧釉质,显微CT扫描并构建牙齿三维数字模型,标记每颗牙齿舌侧面牙本质最薄处为a点并测量该位点牙本质厚度,OCT扫描相同位点处,获取牙本质OCT影像,并测量对应牙本质厚度。测量结果采用Student’s t检验及相关回归分析。结果:同一位点牙本质厚度OCT测量值显著大于显微CT测量值(P=0.004),但两者间呈显著正相关联(R²=0.9877,P＜0.05)。结论:OCT可以用来对髓腔表面牙本质厚度进行无创定量测定。     

应用反求工程方法重建残冠和(或)残根的三维数字模型

目的 探讨用反求工程(RE)方法实现残冠和(或)残根数字模型三维重建的方法,为个体化桩核的CAD设计与制作奠定基础.方法 (1)选取牙体硬组织完整的离体牙10颗,按桩核预备标准预备后分别用螺旋CT机和Mi-CT机进行扫描,所获得数据以DICOM格式文件进行存储;(2)应用Mimics软件将螺旋CT机和Mi-CT机扫描获得的数据分别进行处理,获得牙齿标本的数字模型,Geomagic 9.0软件进行三维测量,同时生成STL格式文件:(3)用游标卡尺对牙齿标本进行测量,并与软件测量所获得的数据进行比较,采用配对比较t检验进行统计学分析.结果 (1)用反求工程方法对离体牙标本实现了三维重建,获得其数字模型.Mi-CT数据源三维数字模型较螺旋CT数据源三维数字模型而言,模型边缘轮廓更为锐利、清晰;(2)应用螺旋CT机和Mi-CT机扫描获得的数字模型,经软件测量,与牙齿标本测量结果相比均无统计学意义(P>0.05).结论 用反求工程方法能准确、快速地实现残冠和(或)残根模型的三维重建.     

锥形束CT对下颌前磨牙髓腔三维重建的精度分析

目的:评价锥形束CT（cone-beam CT, CBCT）对下颌前磨牙髓腔三维重建的精度。方法:选取32颗单根下颌前磨牙,分别采用显微CT(micro-CT)和CBCT进行扫描,对髓腔进行三维重建,分别提取髓腔的三维表面模型和三维体积模型。在Amira 5.0软件中对髓腔表面模型配准后,以micro-CT重建的髓腔模型为参考,检测CBCT重建模型和其相比的形态差异,进行色阶图颜色标示,记录整体形态的三维偏差值并分析2种扫描图像对髓腔体积重建的测量值差异。采用SPSS 13.0软件包对数据进行统计学分析。结果:32颗牙的三维形态偏差RSM值平均为0.27 mm,最大的形态差异分布于髓腔的根尖段和一些细小的解剖变异结构。Micro-CT和CBCT重建髓腔模型的体积测量值分别为(34.89±4.36) mm3和(27.32±4.83) mm3, 差异具有显著性（P<0.05）。结论:利用CBCT扫描图像对下颌前磨牙髓腔进行三维重建时,存在着一定程度的结构丢失,且多位于根尖段和细小的解剖变异部位。口腔临床医师在利用CBCT辅助诊疗时,应考虑到以上特点。     

锥形束CT在牙体牙髓形态学研究中的应用

锥形束CT(cone beam CT,CBCT)影像技术具有图像失真小、空间分辨率高、能够提供三维图像、扫描时间短、辐射剂量较普通CT低等优点,在口腔医学诊疗、教学和科研等方面应用广泛。在牙体牙髓病学领域,利用CBCT既能够比较精准地测量牙体形态特征,亦可有效观测牙髓腔和根管形态特征,特别是对各种特殊的髓腔及根管形态进行有效判断。文章就近年来CBCT在牙体牙髓形态学研究中的应用做一综述。     

髓腔应用解剖和开髓通路

髓腔形态是临床医生进行牙髓病、尖周病治疗的解剖根据 ,在治疗中熟悉髓腔解剖十分重要。后牙根管形态复杂 ,在开髓、寻找根管口、根管预备、根管充填过程中普遍存在费时、根管遗漏或器械折断等问题 ,严重影响工作质量和效率。要高质量地做好各牙的根管治疗术 ,必须熟悉各牙的开髓部位及方法 ,了解髓室大小、髓室底形态、根管口分布及间距、扩大针进入根管的角度和根管长度 ,掌握治疗要点。这样 ,不但会提高医疗质量 ,还会大大提高工作效率。总体来看 :髓腔形态与牙体外形相似 ,髓室形态与牙冠相似 ,根管形态与牙根相似。另外 ,髓腔形态还有…     

光相干成像技术在激光开髓中诊断穿髓的研究

目的 观察频域光相干成像（OCT）系统在激光介导开髓中诊断髓腔穿通的能力.方法 磨除20颗下颌中切牙舌侧釉质,在牙科显微镜下使用铒-YAG激光开髓.激光每作用10s,频域OCT扫描作用位点,并观察髓腔形态,当OCT影像出现髓腔“穿通”提示时,显微CT片上检查是否穿髓.结果 20颗离体牙的OCT扫描图像上出现髓腔“穿通”影像时,CT三维影像上均确认为穿髓.结论 在本研究条件下,频域OCT系统在激光介导开髓中可提供准确的穿髓影像诊断.     

人恒牙根管的解剖特点

髓腔形态是临床医生进行牙髓病和根尖周病治疗的解剖根据之一,在治疗中熟悉髓腔解剖十分重要。临床上由于医务人员对牙体解剖形态以及根管治疗术的常规操作掌握不够熟练,操作失误常常导致患牙治疗失败。     

Evidence of the validity of a model of determinants of quality of restorative dental care

A model describing the relationship between self-reported quality of restorative dentistry and dentist characteristics for 119 Montana general dentists is presented. The best predictors formed a significant model explaining 22% of the variance of the quality measure. Results are contrasted with a previous estimation of the model for 102 Washington general practitioners. Evidence for the external validity of the model is presented.     

Experimental evidence of formation of imines in the course of reduction of hydrazones

The reduction of hydrazones is generally suggested to proceed through a reductive cleavage of the nitrogen–nitrogen bond followed by a reduction of the carbon–nitrogen bond. This sequence of reduction processes is here supported for fluorenone (V) and benzophenone (VI) hydrazones as well as by a comparison of the reduction of fluorenone and benzophenone hydrazonium ions (I,III) with corresponding imines (II,IV). Another proof of the presence of imines as intermediates is the splitting of four-electron waves of hydrazones V and VI and hydrazonium ions I and VIII into two waves at pH < 2. This has been interpreted as due to differences in slopes dE_1/2/dpH and pK_a-values of protonated hydrazine derivatives on one side and corresponding imines on the other. In this pH-range imines formed in reductions of VI and VIII are reduced in a single two-electron wave, those of I and V in two one-electron steps. Fluorenone imine (II) is sufficiently stable to allow recording of time-independent current–voltage curves between pH 6 and 11. In this pH-range the imine (II) is reduced in two one-electron steps. Benzophenone imine (IV) has been found stable between pH 4.6 and 12. At pH 4.6–8 the reduction of the imine IV takes place in a single two-electron step, at pH 8–12 in two one-electron steps. Final proof of the initial cleavage of the N–N bond is presented by comparison with the reduction of nitrones.     

不同剂型玻璃离子水门汀溶解性比较研究

目的:研究、比较不同剂型玻璃离子水门汀的溶解性和表面微观形态改变,为临床使用提供依据.方法:将3M树脂加强型玻璃离子水门汀(水粉剂型)、GC玻璃离子水门汀(水粉剂型)及GC玻璃离子水门汀(双糊剂型)分别在人工唾液中浸泡30 d,冷热循环15000次,烘干测重,比较前后质量变化,计算溶解率,并用扫描电镜观察表面微观改变.结果:不同剂型的玻璃离子水门汀溶解率由高到低分别为3M树脂加强型玻璃离子水门汀(水粉剂型)、GC玻璃离子水门汀(水粉剂型)、GC玻璃离子水门汀(双糊剂型).3种玻璃离子水门汀经浸泡溶解后,SEM扫描表面微观形态可观察到GE玻璃离子水门汀(双糊剂型)表面形态改变较少,其他2组玻璃离子水门汀表面微观改变较多.结论:双糊剂型玻璃离子水门汀理化性能及溶解率均低于传统水粉剂型,是未来临床修复治疗的的良好选择.     

Design of clinical trials of traditional therapies of periodontitis

The present paper on the design of clinical trials of periodontal therapy first addresses the issue of the etiology of periodontal disease. It is suggested that most if not all forms of destructive periodontal disease are caused by microorganisms and that there are different forms of disease with different microbial etiologies. The progressive nature of destructive periodontal disease is subsequently discussed and it is emphasized that, in a given patient, periodontal sites which show signs of inflammation and attachment loss may not over a period of several months and years show further sign of attachment loss. The present methods of assessing periodontal disease do not allow us to discriminate between potentially active and inactive sites in untreated patients. The significance and variability of indicators of periodontal disease such as bleeding on probing, probing pocket depth and probing attachment level measurements are discussed. The errors inherent in the various measurements are analyzed and suggestions are presented describing how alterations in any of the above parameters could be identified and presented in a clinical trial. Of concern for the statistical analysis of clinical data of periodontal disease is the definition of the "experimental unit". For a number of years, the "experimental unit" in periodontal trials was the patient. It is clear, however, that different sites within the same individual show different patterns of disease progression and lesion morphology and often respond differently to periodontal therapy. Statistical analyses must consequently be designed which recognize differences in site-to-site infection and lesion morphology within a common host. Until such analyses are available, the investigator should be wary of pooling data within the same individual, since such pooling may obscure meaningful alternatives which may take place in individual periodontal sites. Some goals of periodontal therapy are subsequently identified. 4 goals are discussed more in detail, namely: to establish conditions which will allow the patient to maintain a dentition without further breakdown of the periodontium; to reduce pocket depth to establish an anatomy in the dentogingival region which with proper maintainance care will prevent the re-establishment of the subgingival infection; to gain attachment as a result of treatment; to assess the effect of a certain chemotherapeutic agent on periodontal disease.     

Evaluation of efficacy of chemiluminescence for diagnosis of leukoplakia

ObjectiveLeukoplakia is the most common potentially malignant disorder preceding oral cancer. Chemiluminescence has been developed as an adjunct to conventional examination for the diagnosis of these potentially malignant disorders. This study was conducted to assess the efficacy of chemiluminescence in the diagnosis of leukoplakia and to compare the results with histopathological examination.Study designA total of 50 patients with leukoplakia were included from the outpatients attending the Department of Oral Medicine and Radiology, Dental Hospital, Bengaluru, Karnataka, India. These patients were subjected to conventional oral examination followed by chemiluminescent examination with Vizilite (Zila, Fort Collins, CO, USA) and biopsy for histopathological confirmation.ResultsThe sensitivity, specificity, positive predictive value, and negative predictive value of chemiluminescence were 93.75%, 55.56%, 78.95%, and 83.3%, respectively. The overall accuracy of chemiluminescence was 80%. A statistically significant association was observed between histopathology results and chemiluminescence results.ConclusionAlthough it is an easy, safe, minimal time consuming, and noninvasive technique, it has only adjunctive utility and it does not replace biopsy for the diagnosis of leukoplakia.     

颌骨动静脉畸形的栓塞治疗

目的：总结直接穿刺结合经血管内介入栓塞治疗颌骨动静脉静脉畸形的经验。方法：收治凳骨动静脉畸形患者6例,均进行了介入栓塞治疗。采用的栓塞材料为附凝血棉纤毛的螺圈,聚乙烯醇泡沫微粒和二氰基丙烯酸对丁酯。数字减影颈动脉造影在PHILIPSV300下完成。结果6例颌骨动静脉畸形患者中4,例急性出血得到了快速、有效控制,1例慢性渗血的右下 骨动静脉畸形患者,介入栓塞治疗,拔除松动的右下凳第一磨牙,有效地控制了出血,另1例伴局部软组织搏动性膨隆的上凳骨动静脉畸形患者,介入治疗后膨隆的搏动性得到明显改善,栓塞治疗后分别随访3－24个月,均未发现有口腔内渗血或出血。随访的X线片上,病灶区可见新骨形成。结论：局部穿刺结合经血管内介入栓塞治疗颌骨动静畸形是一种安全、有效的治疗方法。     

正畸患者切牙影像失真发生情况分析

目的研究正畸患者曲面体层片上的切牙影像失真发生情况，并分析其原因。 方法从中山大学附属口腔医院放射科影像数据库中选取500例正畸患者的曲面体层片和头影测量侧位片，所有曲面体层片均采用咬合杆投照，分别从切牙牙体影像放大、缩小、牙根变短、根尖模糊等评价指标分析上下颌切牙影像失真的发生情况，在头影测量侧位片上测量中切牙根尖-对颌切牙切缘的距离，探讨切牙影像失真发生的原因。采用SPSS 19.0统计软件对所得数据进行统计学检验。 结果500例患者中，切牙牙体影像正常者共417例，切牙牙体影像失真者共83例，影像失真发生率16.6%，其中切牙牙体影像放大17例、牙体影像缩小0例、牙根变短30例，牙根影像变短伴模糊36例。影像失真患者的根尖-切缘距离大于影像正常的患者，差异有统计学意义（F = 5 187.18，P = 0）；影像失真患者的覆盖值大于影像正常的患者，差异有统计学意义（F>477，P = 0）。 结论严重牙颌面畸形如反 、深覆盖是导致曲面体层片的切牙影像失真的主要原因之一。     

正常青年Monson球面半径的测量研究

目的测量正常青年Monson球面半径。方法选择60名(男30名,女30名)正常青年制取全口印模,应用立体摄影成像的原理与方法对Monson球面半径进行测量和统计学处理。结果Monson球面的半径平均为10.173 cm,大于理论值10.160 cm,差异有显著性(P<0.01);男、女性球面半径差异无显著性。结论本实验所得到的数据可作为全口义齿修复中记录颌位关系的一个参量。     

鼻测量法的进展

唇裂术后继发畸形是指唇裂修复术后,仍遗留或继发于手术操作和生长发育变化而表现出来的一类畸形[1]。包括唇畸形、鼻畸形和颌骨畸形。其修复较原发性唇裂修复更复杂,更灵活多变。而导致其修复复杂性的一个重要原因即是局部组织结构复杂变异和缺乏可靠的三维测量手段[2],鼻畸形