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。     

上颌第一前磨牙根尖区根管横截面形态的研究

目的 研究上颌第一前磨牙根尖区根管横截面的形态.方法 选择15个上颌第一前磨牙(单根牙11个,双根牙4个),利用Isomet低速金刚砂切片机,在距解剖根尖1、2、3、4、5、6 mm处垂直牙体长轴切割.然后在牙科手术显微镜下,利用Photoshop CS 8.0软件测量各截面根管的颊舌径和近远中径,按标准记录根管横截面的形态.结果 共获得切片111个,根管共138个,其中长椭圆形根管发生率为42.0%.单根管牙的颊舌径大于近远中径,以长椭圆形根管形态为主,其发生率向根尖降低;双根牙的颊根管颊舌径大多小于近远中径,但腭根管颊舌径均大于近远中径,长椭圆形根管发生情况更复杂.结论 上颌第一前磨牙根尖区根管横截面形态复杂,可能影响根管治疗的质量.     

乳牙髓腔形态的影像学研究

目的:探讨乳牙髓腔形态规律。方法:利用RVG数字成像系统采集乳牙唇(颊)-舌向和近-远向X图像,观察髓腔形态并测量相关数据,将测量结果进行统计学分析。结果:乳前牙髓室和根管在牙颈部相连续,无明显界限,大多数乳前牙唇-舌位片显示根尖1/3段根管随牙根明显向唇侧弯曲并且上颌牙比下颌牙明显。上颌乳切牙根颈、根中1/3冠端处根管的唇舌径小于近远中径,而下颌乳切牙则相反,其差异有统计学意义(P<0.05)。乳尖牙根颈、根中1/3和所有乳前牙根尖1/3冠端处根管的唇舌径和近远中径大小无统计学意义。上乳磨牙髓室关系为:颊舌径>近远中径>髓室高度;下颌乳磨牙髓室关系为:近远中径>颊舌径>髓室高度。结论:本研究获得乳牙的RVG数字成像系统的实验结果可为临床应用提供参考。     

上颌第一前磨牙根管锥度的研究

目的：研究上颌第一前磨牙的根管锥度。方法：将离体的101个上颌第一前磨牙髓腔作＂颊－舌向＂和＂近－远中向＂X线摄影后输入计算机行图象处理,统计该牙根管全长数值、根管中1／2处颊－舌向直径和近－远中向直径、距根尖端0．5 mm处根管的颊－舌向和近－远中向直径,然后代入公式计算根管的锥度。结果：上颌第一前磨牙根管平均长11．4 mm,根管中段颊－舌径平均宽1．8 mm、近－远中径平均宽0．8 mm,靠近根尖的根管颊－舌径平均宽0．6 mm、近－远中径平均宽0．4 mm;将上述数值代入公式得到该牙根管下段的锥度,在颊－舌象限为0．175,在近－远中象限为0．035。结论：上颌第一前磨牙根管下段并非呈圆锥形空间,而是呈颊－舌径＞近－远中径的扁形腔隙;该牙根管预备之初,选择Profile的I号锉较为适宜。     

13～23岁下颌第二前磨牙单根管锥度的初步研究

目的探讨青少年下颌第二前磨牙单根管的初始锥度。方法收集牙体完整的13～23岁单根管离体下颌第二前磨牙23颗,采用显微CT对标本从根尖向冠方进行断层扫描,将每个根管平均分为3段,通过3ddoctor软件测量根管的近远中向管径及颊舌向管径,计算这3个水平段颊舌向和近远中向根管锥度。结果根管近远中向锥度由根冠至根尖分别为0.06、0.08、0.07,颊舌向锥度由根冠至根尖分别为0.32、0.21、0.25。颊舌向3段锥度之间的差异均有统计学意义（P<0.05）,而近远中向3段锥度之间的差异无统计学意义（P>0.05）。结论13～23岁单根管下颌第二前磨牙根管颊舌向锥度变化明显,最小的锥度在根中1/3。近远中向锥度较颊舌向小,但根管上下差别不大。     

GuttaFlow结合不同锥度牙胶尖充填质量的体外评价

目的：对常温牙胶充填系统GuttaFlow采用不同锥度牙胶尖充填质量进行体外评价。方法：将40颗上颌切牙经K3预备至0.06锥度40号后,随机分为0.02锥度组和0.06锥度组,分别用多根0.02锥度牙胶尖和单根0.06锥度牙胶尖,结合GuttaFlow进行根管充填。使用RVG摄像系统,对每颗牙颊舌向、近远中向进行X光投照后评分。包埋冠部,自根尖向冠方垂直于牙体长轴每隔1mm制备横截面切片。体视显微镜下观察切片中空隙的分布与面积。结果：0.02锥度组近远中向及双向整体评分、空隙的发生率及距根尖5～8mm水平的空隙横截面数均显著高于0.06锥度组;其他观察指标两组之间无显著性差异。近远中向评分与空隙面积百分比显著相关。结论：使用GuttaFlow系统进行根充时,推荐采用与根管预备锥度相一致的主牙胶尖,并且根管上段可适当增加辅尖。     

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.     

下颌第三磨牙的解剖形态观察

目的：探讨下颌第三磨牙的解剖外形及其根管口的形态特点,为牙体牙髓病的临床治疗提供理论依据.方法：收集临床拔除的下颌第三磨牙159颗,观察牙尖和牙根数目,测量牙体长度、牙冠最大近远中径和最大颊舌径;拍摄颊舌向和近远中向X线初始片;开髓、拔髓、疏通根管,体视显微镜测量各根管口之间的距离.结果：外形上,下颌第三磨牙根长大于冠长,近远中径大于颊舌径.单根居多,占54.09%,其次是两根,占40.51%.下颌第三磨牙的根管数目1～4,以两根管（55.35%）居多.S型根管14例,C型根管36例（22.80%）,其中Ⅰ型50.0%,Ⅱ型36.1%,Ⅲ型13.9%.多根管牙的各根管口之间的距离最小0.35 mm,最大5.00mm;均值2.13～3.95.结论：下颌第三磨牙根管系统较为复杂,可以出现C型、S型及弯曲根管.     

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。     

三根型下颌第一恒磨牙根尖解剖结构的显微CT观测

目的 揭示三根型下颌第一恒磨牙根尖解剖特点,以期为临床进行根管治疗提供依据.方法 从江苏省吴江市第一人民医院口腔科门诊采集中国汉族患者拔除的下颌第一恒磨牙122颗,选择20颗三根型下颌磨牙(三根组)及25颗双根型下颌磨牙(双根组)进行显微CT扫描及三维重建.Mimics 10.01软件界面下观测根尖部的解剖结构,测量根尖狭窄的长、短径,根尖孔、根尖狭窄与根尖端的距离;两组牙齿不同根管间根尖狭窄直径及其与根尖孔、根尖端距离的比较采用单因素方差分析及LSD-t检验,以P＜ 0.05为差异有统计学意义.结果 近颊根管根尖孔最多见于根尖远中侧(三根组10个,双根组6个),近舌根管多见于舌侧(三根组及双根组各8个);远颊根根尖孔多位于根尖远中舌侧(10个),远舌根根尖孔常偏向颊侧(7个);双根组远中根管根尖孔大多偏向远中(11个).典型的沙漏状根尖狭窄出现率为53％( 80/151).三根组远颊根管根尖狭窄的长、短径分别为(0.32±0.09)、(0.25±0.05) mm,显著大于远舌根管[长、短径分别为(0.27±0.08)、(0.22±0.06) mm,P＜ 0.05]及近舌根管[长、短径分别为(0.24±0.06)、(0.19±0.06)mm,P＜ 0.01].三根组根尖孔至根尖狭窄及根尖端的平均距离分别为(0.67±0.32)和(0.49±0.28) mm,根尖狭窄至根尖端平均距离为(1.01±0.34) mm.结论 三根型下颌第一恒磨牙根尖孔往往偏离根尖端,根尖狭窄在远颊根管最宽大;根尖狭窄、根尖孔及根尖端间距的测量可以为根管治疗时确定工作长度提供参考.     

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.     

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。     

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.     

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     

口底癌34例临床分析

目的探讨口底癌的临床特性、治疗方法及预后。方法对我院自1992—2002年住院治疗的34例口底癌患者进行回顾性分析。结果34例口底癌患者中,男28例(82.4%),女6例(17.6%),男女比为4.7∶1,平均发病年龄58岁。发病部位:前口底22例(64.7%),后口底12例(35.3%)。淋巴结转移率41.2%。单纯手术组、化疗加手术组、放疗加手术组、化疗加手术加放疗组的5年生存率分别为45.5%、60.0%、50.0%、62.5%。结论口底癌以中老年患者好发,男性居多。易发生淋巴结转移,综合疗法疗效较好。