钛网加强的BMSC/松质骨基质修复下颌骨缺损的实验研究

目的：观察钛网加强的骨髓基质细胞(BMSC)／松质骨基质复合物修复下颌骨缺损的能力。方法：体外培养兔BMSC经扩增，诱导分化后复合同种异体松质骨基质，植入自体下颌骨缺损区，修复骨缺损，钛网固位和加强，植入6周、12周后经X线，组织学检查，观察骨形成情况。结果：骨髓基质细胞(BMSC)/松质骨基质复合物有很强的成骨作用，实验组X线观察有骨形成，组织学染色证实有新骨形成，骨磨片显示钛网和新骨获得良好的愈合。结论：钛网加强的BMSC／松质骨基质可诱导修复兔下颌骨缺损，为组织工程方法修复骨缺损提供了新的思路。     

钛网加强组织工程骨修复下颌骨缺损的实验研究

目的:观察钛网加强的珊瑚/成骨细胞复合体修复下颌骨缺损的情况。方法:在羊下颌骨上造成3．5cm×1．5cm大小的骨缺损,缺损中植入钛网/珊瑚/成骨细胞,并设单纯珊瑚颗粒植入作为对照组。术后4个月取材,观察骨缺损的修复情况。结果:X线观察示实验组骨密度增加,大体观察见下颌骨下缘连续性恢复。4个月时,羊下颌骨缺损完全修复,组织学检查见支架中有大量新骨形成,并与钛网相融合。对照组X线检查示透光增加,组织学检查见吸收明显。结论:利用钛网加强的方法可以有效修复下颌骨矩形骨缺损。     

大鼠骨髓基质细胞与胶原-壳聚糖复合后修复牙槽骨缺损的研究

目的：以大鼠骨髓基质细胞为种子细胞，胶原一壳聚糖复合物为支架材料，通过骨组织工程的原理和方法修复牙槽骨缺损。方法：将28只SD大鼠分为实验组和对照组，实验组取大鼠骨髓基质细胞进行体外培养并矿化诱导为成骨样细胞，植入胶原一壳聚糖复合物培养1周后，植入大鼠下颌骨缺损处，2周、4周后取材。对照组细胞未进行诱导。结果：骨髓基质细胞矿化诱导后表现出与成骨细胞相似的形态学与功能表现，ALP染色阳性，并形成矿化结节，细胞在胶原一壳聚糖复合物内伸展良好，组织学观察：实验组2周后可见有少量新骨形成，4周后新骨形成面积增大对照组无明显新骨形成，材料周围有炎细胞浸润。并可见部分纤维结缔组织包绕。结论：利用胶原一壳聚糖复合物与诱导后的BMSC复合有良好的新骨形成能力。对临床修复唇腭裂骨缺损并进行正畸治疗有良好的应用前景。     

犬下颌骨节段性缺损的个体化再生修复实验研究

目的:通过实验观察犬下颌骨节段性缺损个体化再生修复的效果,为计算机辅助个体化再生修复下颌骨缺损的技术和方法向临床过渡提供依据。方法:利用计算机辅助设计/制作、快速原型技术等设计制作实验动物下颌骨个体化三维中空钛网修复体,再将其与β-磷酸三钙和松质骨髓植入联合应用于犬下颌骨节段性缺损的修复,通过X线片、大体标本和组织学切片对下颌骨节段性缺损的个体化再生修复效果进行观察。结果:犬下颌骨解剖形态恢复十分理想,组织学和X线摄影观察显示钛网内具有新骨形成,新生骨在3个月时已十分明显和成熟。结论:将计算机辅助技术与骨再生材料联合应用,可望通过骨再生途径实现下颌骨节段性缺损的个体化修复重建。     

自体骨髓基质干细胞-珊瑚羟基磷灰石修复下颌骨节段缺损的实验研究

目的应用骨髓基质干细胞（BMSCs）复合珊瑚羟基磷灰石（CHA）构建组织工程化骨，修复犬下颌骨节段性缺损。方法体外分离培养，成骨诱导扩增犬BMSCs，将第2代细胞复合CHA后修复5只犬自体下颌骨右侧3cm的节段缺损；6只犬植入单纯CHA作为对照，术后12、26、32周通过影像学、大体形态、组织学和生物力学的方法检测骨缺损的修复效果。结果BMSCs-CHA复合物生长良好。随时间延长，X线片和CT显示实验组连接处骨痂形成，实验对照组连接处始终愈合较差；32周大体观察实验组骨修复较好，组织学显示有板层骨形成，连接处骨性愈合，实验对照组有编织骨形成，连接处纤维愈合。实验组与正常对照组下颌骨力学强度差异无统计学意义。结论自体成骨诱导BMSCs复合CHA形成的组织工程化骨可修复犬下颌骨节段缺损。     

hBMP-7基因修饰犬骨髓基质干细胞复合珊瑚羟基磷灰石修复下颌骨缺损

目的:构建携带人骨形态发生蛋白7(hBMP-7)基因的重组腺病毒载体,体外转染犬骨髓基质干细胞(dMSCs)复合珊瑚羟基磷灰石(coral hydroxyapatite, CHA),观察其修复下颌骨缺损的效果。方法:利用AdEasy腺病毒表达系统,体外构建高效表达hBMP-7重组腺病毒载体,转染dMSCs 与珊瑚羟基磷灰石支架材料复合,再分别植入取材动物的自体下颌骨缺损区,分别于4周和8周取材观察成骨情况。结果:大体观察、X线检查及组织学观察均发现构建组织工程骨在祼鼠皮下及骨缺损处均有明显新骨组织形成。结论:构建携带人骨形态发生蛋白7(hBMP-7)基因的重组腺病毒载体,体外转染dMSCs后复合珊瑚羟基磷灰石有较多量骨组织形成,可有效修复下颌骨缺损。[关键词] 人骨形态发生蛋白7 骨髓基质干细胞 腺病毒 组织工程     

鸵鸟骨转化多相钙磷陶瓷用于组织工程支架修复颅骨缺损实验研究

目的 观察鸵鸟骨转化多相钙磷陶瓷支架用于组织工程支架修复颅骨缺损的成骨性能.方法 来源于髂骨松质骨的自体骨髓基质细胞经含地塞米松、抗坏血酸、β-甘油磷酸钠的诱导液培养,直至培养皿底部形成一层膜性结构,用该膜性结构包绕多相钙磷陶瓷支架后将其植入兔颅骨缺损区.单纯支架材料植入和不植入材料作为对照.植入后4 w、8 w取材,通过X线片分析、大体和组织学观察评价其成骨性能.结果 支架/细胞复合物植入后4 w,在材料表面及孔隙内形成部分成熟骨和骨髓组织;植入后8w,更多的成熟骨形成,新形成的组织工程骨与颅骨融合.结论 支架/细胞复合物能够有效地修复颅骨缺损,鸵鸟骨转化多相钙磷陶瓷可能成为一种有发展前景的骨组织工程支架材料.     

组织工程方法进行特定形态骨组织构建的研究

目的 用组织工程方法构建人下颌骨升支外形的骨组织。方法 体外培养、扩增、诱导兔骨髓基质干细胞（MSCs）,细胞长满后用基因重组人骨形成蛋白-2诱导 3天;收集细胞,按 5×107/ml的浓度混匀至 1.5％藻酸钠溶液中,然后接种于人下颌骨升支外形的多孔珊瑚中,以CaCl2固化后,植入裸鼠背部皮下组织中,于植入术后1、2个月取材,通过大体标本、X线检查、组织学检查观察新骨的形成情况。结果2月时形成的组织在裸鼠背部界限清晰,取材后观察珊瑚表面有坚硬组织形成,形状与支架材料的外形基本一致,X线检查证实珊瑚已有明显吸收,在其表面有明显X线组射影形成;组织学检查表明,在珊瑚表面及内部的孔洞内均有大量新骨形成,新骨形成过程为软骨内成骨。结论 用组织工程方法可以构建出特定形态骨组织,因此适于进行颌面部骨缺损的修复。     

钛网成形自体颗粒骨修复下颌骨缺损并同期种植的实验研究

目的 观察犬钛网成形自体颗粒骨移植修复下颌骨节段性缺损并同期植入钛种植体后的骨愈合和骨结合情况.方法 5只Beagle犬,一侧下颌骨制备长40 mm的节段性缺损;钛网成形修复下颌骨缺损.将切除后的下颌骨和自体髂骨剪成直径约2mm颗粒,骨皮质、骨松质体积比3∶1混合,紧密充填在钛网内,将2枚纯钛种植体埋置于颗粒骨内,术后6个月处死动物.用下颌骨X线片、组织学切片、扫描电镜以及能谱分析观察钛网内颗粒骨愈合以及种植体骨结合的情况.结果 钛网成形自体颗粒骨移植重建后的下颌骨外形满意,功能正常、颗粒骨成骨良好、结构优良,未见明显骨吸收.同期植入的种植体能够与周围骨组织形成良好的骨结合,并有促进邻近骨组织结构优化的趋势.结论 钛网成形自体颗粒骨移植是一种修复下颌骨节段性缺损的好方法,当修复后下颌骨形态良好、骨质优良、骨量充足时可以同期植入种植体.     

骨髓来源成骨细胞接种于珊瑚中再造下颌骨髁状突的研究

目的：研究用组织工程方法再造人下颌骨髁状突形状骨组织的可行性。方法：W本外培养、扩增、诱导兔骨髓基质干细胞（MSCs)、将细胞接种于人工下颌骨髁状突形状的多孔珊瑚中,植入裸鼠背部皮下组织中,术后1、2月取材,通过大体标本观察、X线检查,扫描电镜观察、组织学检查,观察新骨的形成情况。结果：大体标本观察,2月时成功地再造出具有髁状突解剖形态的骨组织、X线检查表明新组织骨骨和未降解的珊瑚构成;扫描电镜和组织观察均证明在珊胡表面和孔洞内有大量新骨形成,结论：骨髓来源成骨细胞接种于珊瑚中再造成特定形成骨组织的有效方法。     

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.     

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.     

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.     

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。     

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。     

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。     

Electrodeposition of bilayers of dithiols

We report an electrochemical method to form a bilayer of dithiol. The cyclic voltammogram of the oxidative deposition of an aromatic dithiol on gold from an alkaline aqueous solution reveals two current peaks separated by more than 400 mV. The integrated charge of the oxidative current peak (B) at the most positive potential is twice that of the other oxidative current peak (A). These two oxidative current peaks were characterized by differential capacitance and electrochemical quartz crystal microbalance (EQCM) measurements. A decrease of the capacity by a factor of two, and an increase of the EQCM frequency change by a factor of two were observed when the potential was scanned from a value where only the first oxidative peak (A) is obtained, to a potential where both oxidative current peaks (A and B) are obtained. Infrared spectra show that the aromatic dithiols adsorb vertically at potentials corresponding to the current peak A and they become tilted for potentials corresponding to the current peak B. The simple relationships between the properties of the two oxidative current peaks are found to be compatible with a step-wise oxidative deposition of a bilayer of dithiol.