中国人下颌恒切牙根管弯曲的解剖学研究

目的 探讨下颌恒切牙根管弯曲情况。方法 选择299颗离体下颌恒切牙,将15号K锉插入根管,唇舌向和近远中向采集数字化X线牙片图像,测量根管的弯曲角度、弯曲半径以及弯曲长度,并根据弯曲角度和弯曲形状进行分类。对测量结果进行统计分析。结果 下颌恒切牙根管的弯曲角度、弯曲半径以及弯曲长度,唇舌向分别为5.28°±5.52°、16.19 mm±12.38 mm、4.10 mm±2.01 mm,近远中向分别为9.99°±5.84°、18.86 mm±9.71 mm、3.27 mm±2.39 mm。下颌恒切牙根管中直根管、轻度、中度、重度弯曲根管分别为15.7%、66.9%、16.7%和0.7%（P<0.05）;直根管、单弯根管、双弯根管分别为7.7%、50.5%和41.8%（P<0.05）。结论 下颌恒切牙以弯曲根管为主,唇舌向弯曲程度大于近远中向弯曲程度。     

回族和蒙古族成人前牙牙根弯曲情况比较研究

目的了解回族和蒙古族成人前牙根管弯曲情况。方法采用间接影像学手段,运用改良的Schneider测量方法,利用电子测量尺进行测量、分析两民族的根管弯曲情况。结果回族和蒙古族前牙根管多为Ⅰ型根管,且弯曲多发生在靠近根尖1／3处,回族下颌侧切牙、尖牙根管唇（颊）舌向弯曲发生率分别为（54．55％、68．42％）,与汉族接近,但明显高于蒙古族（17．65％、23．53％）,其间的差异具有统计学意（P〈0．05）;回族下颌中切牙近远中向的弯曲度明显大于汉族和蒙古族（P〈0．05）。回族上颌侧切牙及尖牙根管在唇舌方向的弯曲长度与汉族接近,均小于蒙古族（P〈0．05）,回族下颌中切牙根管在唇舌方向的弯曲长度与汉族接近,但大于蒙古族（P〈0．05）。S形根管在两民族前牙的发生比率相对较小。结论回族和蒙古族前牙根管弯曲情况与汉族一样较为复杂,不同种族的前牙根管弯曲情况确有差别。     

壮族人群恒前牙根管弯曲度测定

目的了解壮族人群恒前牙的根管弯曲情况。方法收集新鲜拔除的壮族人群恒前牙245颗,采用间接影像学手段观察其根管类型和弯曲形状,在Schneider法和Sch覿fer法的基础上,结合电子测量尺软件测量分析218颗Ⅰ型根管牙齿的弯曲度、弯曲半径和弯曲长度。结果壮族人群恒前牙以Ⅰ型根管为主,有13颗下颌中切牙和12颗下颌侧切牙为Ⅱ、Ⅲ、Ⅳ型根管。上颌中切牙、侧切牙、尖牙以及下颌中切牙、侧切牙、尖牙Ⅰ型根管近远中向弯曲发生率分别为40%、80%、77%、65%、66%、73%,唇舌（腭）向弯曲发生率分别为62%、69%、70%、62%、41%、61%。弯曲部位多在根尖1/3,多为中度弯曲;上颌尖牙在近远中向上的根管弯曲度最大,下颌尖牙在唇舌（腭）向上的根管弯曲度最大;上颌侧切牙在近远中和唇舌（腭）2个方向上的根管弯曲半径及弯曲长度均较小。结论壮族人群恒前牙根管弯曲情况较复杂,其下颌切牙Ⅱ、Ⅲ、Ⅳ型根管发生率较高。     

数字化牙片确定前牙根管工作长度准确性的研究

目的：探讨如何在数字化牙片上确定根管工作长度。方法：收集离体前牙99颗（共99个根管）作为研究对象。开髓后,放入牙胶尖至解剖根尖孔处稍后退;使用平行投照法在唇舌向拍摄数字化 X线片,标定数字化牙片与牙体的放大比例;在数字化牙片和离体牙上测量牙胶顶点到根尖顶点的距离,观察牙胶顶点在牙体和在牙片上的位置,并比较两者差异。结果：使用平行投照法拍摄数字化 X线片,所得牙齿影像与实际牙体的放大比率为1∶1;X 线片和离体牙上解剖根尖孔距离根尖顶点的平均距离差异没有统计学意义（P＞0．05）。X线片和离体牙上根尖孔的侧方开口率均接近50％,侧方根尖孔与根尖顶点的距离大于正方根尖孔与根尖顶点的距离（P＜0．01）。结论：以数字化牙片确定根管工作长度是一种比较准确的方法,但在临床使用时需结合根尖孔与根尖的关系以确定最佳工作长度。     

离体下颌前磨牙根管的颊舌向弯曲

目的：确定人下颌第一、二前磨牙的颊舌向根管弯曲程度和情况。方法：离体第一前磨牙69个，第二前磨牙93个，摄近中远中向的X线片，用Photoshop5．0软件分析根管，用Weine氏法测量根管的弯曲度，测量角度大于18度时，则认为根管存在明显的弯曲，根管的构型采用Vertucci分类法。结果：下颌第一前磨牙根管颊舌向弯曲牙齿的发生率是7.2％（5／69），下颌第二前磨牙根管颊舌向弯曲牙齿的发生率是5．3％（5／93），二者之间无明显的差异（P〉0．05）。结论：下颌前磨牙颊舌向的根管弯曲发生率较低。     

上颌中切牙双根双根管1例报道

患者 ,女 ,70岁。右上中切牙为孤立牙 ,牙冠形态正常 ,近中牙颈部深龋 ,因修复需要局麻下拔除 ,发现为唇舌向分根牙 ,根分叉位于根尖 1/ 3处 ,经舌面开髓后插入光滑髓针 ,摄X线牙片显示为双根管 (见图 1)。上中切牙有双根与双根管畸形的可能 ,由于为唇舌向分根并重叠 ,常规X线片很难发现 ,临床上对于上颌中切牙根管治疗后出现疼痛或慢性瘘管等表现时 ,在排除其他原因的情况下 ,应考虑是否有分根畸形而遗漏根管未作治疗的可能。　　图 1　上中切牙双根双根管畸形上颌中切牙双根双根管1例报道@郭家平$广州军区武汉总医院口腔科!湖北武汉43007…     

487颗下颌前牙根管的弯曲情况研究

目的:了解下颌前牙根管弯曲情况。方法:采用间接数字化X线成像技术拍摄487颗下颌前牙的近远中 向和颊舌向X线影像,分析根管的弯曲情况。结果:下颌前牙根管以Ⅰ型为主。26.22%的下颌切牙和31.45%的 下颌尖牙出现近远中向弯曲,7.01%的下颌切牙和18.87%的下颌尖牙出现颊舌向弯曲。下颌切牙Ⅰ型弯曲根管 颊舌向弯曲度(M=15.8°)最大;其弯曲半径(M=4.7mm)和弯曲长度(M=2.6mm)最小。结论:下颌前牙根管的 弯曲情况较复杂,以下颌切牙为甚。     

离体下颌前牙唇舌向根管形态的研究

目的观察离体下颌前牙唇舌向根管形态及弯曲情况，为掌握正确地开髓方向提供依据。方法采用间接数字化x线成像技术，对收集的离体105颗下颌前牙进行近远中向拍摄，根据Weine根管分类标准，观察根管类型；采用改良Schneider测量方法，分析根管弯曲情况。沿下颌前牙近远中向x线片根中1／3画延长线，观察延长线在下颌前牙切端的位置。结果下颌前牙根管在唇舌向半数以上存在弯曲，根尖多数弯向唇侧，弯曲部位多集中在根尖1／3。结论下颌前牙根管形态较为复杂，弯曲率较高，开髓方向应靠近切缘。     

数字化X线牙片和体视显微镜测量根管锥度的体外研究

目的: 通过数字化X线牙片和体视显微镜测量根管锥度,获得下颌第一前磨牙根管的初始锥度,为根管器械材料的锥度设计和临床正确选择锥度器械提供参考.方法:应用数字化X线牙片机,采用平行投照技术,分别从颊舌向和近远中向对23个13～23岁下颌第一前磨牙(单根管)根管进行摄片,通过相应图像分析软件对根管冠、中、根尖各段的管径及长度进行测量;然后通过制样机对同组样本1 mm等距离磨除,利用体视显微镜对断面根管管径进行摄片及测量.分析整理数据,通过相应数学公式计算各组根管锥度.结果:通过X线片得到根管近中远中向锥度分别为0.03、0.07、0.09;颊舌向分别为0.09、0.24、0.19.体视镜得到近中远中向锥度0.07、0.06、0.07;颊舌向为0.15、0.24、0.17.两种方法所得对应结果经t检验均无显著性差别(P＞0.05).结论:①13～23岁下颌第一前磨牙根尖1/3段的锥度近中远中向为0.07～0.09,颊舌向为0.17～0.19,对于该年龄段根管,0.07～0.09锥度器械较适合;②数字化X线牙片平行投照可准确得到该牙根管的锥度;③该组牙颊舌向根管的中1/3段锥度明显大于冠1/3段,根管预备中可导致根管冠1/3段(尤其是根管口)颊舌侧壁的过度切割.     

下颌切牙根管形态特征的研究

目的 :研究下颌切牙根管的形态特征、数量及变异情况。方法 :采用X线片法拍下颌切牙唇舌向、近远中向X线片 ,观察根管形态、数量、长形下凹与多根管的关系 ,测量管壁厚度。结果 :下颌切牙根管壁的厚度依次为 :舌侧壁 >唇侧壁 >近远中壁 ,中、侧切牙的根管长度分别为 (12 .96± 6.46)mm和 (11.47± 6.3 2 )mm ;中、侧切牙双根管率分别为 3 5 .9%和 2 7.5 % ;多数存在长形下凹者为单根管。结论 :下颌切牙根管壁近远中向薄 ,双根管率高 ;长形下凹的存在与根管数无显著关系。     

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