牙周膜来源细胞膜片在牙周再生中的应用研究进展

牙周炎作为危害口腔健康的严重疾病之一,其引起的牙周支持组织的损害和丧失却得不到良好的治愈,使得患者的生活质量严重下降。细胞膜片技术作为细胞移植的一种新方法,可以减少细胞的流失,提高细胞的利用率,且在移植的过程中无需外源性支架材料,其在牙周组织工程中表现出了巨大的潜力。本文就组织工程中细胞膜片技术及牙周膜来源的细胞膜片在牙周再生中的研究进展做一综述。     

构建一种新型牙周膜牙囊复合细胞膜片的研究

目的：拟构建一种牙周膜牙囊复合细胞膜片,并比较其与单一膜片的性能差异,以期寻找一种更加优越的牙周缺损修复材料。方法：将第三代牙周膜干细胞及牙囊干细胞直接混合共同培养,将牙周膜牙囊混合细胞、牙周膜干细胞及牙囊干细胞分别制备成细胞膜片,应用HE染色,扫描电镜比较三种膜片形态学差异,应用茜素红染色,RT—PCR比较三种膜片成骨能力差异。结果：扫描电镜结果显示,牙囊牙周膜混合细胞膜片分泌更多的细胞外基质。HE染色结果也显示牙囊牙周膜混合细胞膜片细胞层数更多,基质分泌量更大。同时,牙囊牙周膜混合细胞膜片AIJP、Runx2、OCN表达显著高于单一细胞膜片。成骨诱导21天后,茜素红染色结果显示,与单一细胞膜片相比,牙囊牙周膜混合细胞膜片染色更深。结论：牙周膜牙囊复合细胞膜片较单一细胞膜片,细胞层数更多,基质分泌量更大,骨向分化能力更强,为牙周再生提供了新的思路。     

牙周韧带细胞膜片技术用于牙周组织再生的研究进展

为了解决中重度牙周炎引发的牙周组织破坏后无法自主再生的问题,细胞膜片工程根据引导性组织再生术的基本原理,通过将使用温敏培养皿等方法获取的完整细胞片层直接移植贴附到缺损部位的方法,实现获取牙骨质、牙槽骨及嵌入二者的牙周韧带同时再生的目标.近年来,细胞膜片技术不断发展,逐步克服了单层细胞膜片厚度偏低、血管化不良及自体细胞来源不足等问题,其中运用牙周韧带细胞膜片进行牙周组织再生已经正式进入临床试验阶段.本文对近年来牙周韧带细胞膜片及其他常用细胞膜片在牙周组织再生方向应用的新进展作一综述.     

根尖牙乳头干细胞细胞膜片构建及其成骨/成牙本质分化性能研究

目的:构建根尖牙乳头干细胞（stem cells from apical papilla, SCAP）细胞膜片,并对其组织学形态和成骨/成牙本质分化性能进行研究,为SCAP细胞膜片应用于年轻恒牙牙髓再生提供实验基础。方法:分离年轻恒牙第三磨牙牙乳头,进行SCAP原代培养。采用流式细胞术检测SCAP表面标志物,茜素红S染色检测其成骨/成牙本质分化。取第3代SCAP,膜片诱导液连续培养14 d,形成细胞膜片。对SCAP细胞膜片进行H-E染色,组织学观察;流式细胞术检测SCAP细胞膜片的细胞周期变化;实时定量PCR（qRT-PCR）检测细胞膜片中Runx2、ALP、Col-I基因表达;Western印迹法检测细胞膜片Runx2、ALP蛋白表达水平。采用SPSS17.0软件包对实验结果进行统计学分析,两样本细胞周期检测和qRT-PCR基因检测均数的比较采用t检验。结果:组织学H-E染色显示,SCAP细胞膜片由5~6层细胞组成,细胞量大,细胞之间排列紧密,且富含细胞外基质。SCAP细胞膜片细胞周期G2+S期所占比例较低,而G1期比例较高,提示SCAP细胞膜片增殖性能受到显著抑制（P<0.05）。同时,qRT-PCR和Western印迹法结果显示,与SCAP相比,SCAP细胞膜片成骨/成牙本质分化能力显著升高（P<0.05）。结论:SCAP细胞膜片富含细胞外基质,且成骨/成牙本质分化能力高于单纯SCAP,SCAP细胞膜片应用于牙髓再生更具有优势。     

组织工程细胞片在牙周组织再生中的作用

牙周组织工程系指将在体外以理想的种子细胞和细胞外基质构建的具有生命活性的复合体植入牙周缺损部位,对牙周缺损部位进行结构功能性重建。组织工程细胞膜片构建主要有温敏培养皿、刮取法、胶原凝胶法、磁力组织工程法、表面粗糙颗粒单分子层法和聚合电解质等。牙周组织工程细胞片主要有牙周膜干细胞和骨髓间充质干细胞片,分别将其与不同的载体叠加并植入动物体内,可发现细胞外基质和纤维黏附,牙骨质样组织和牙周组织再生。将人牙周膜成纤维细胞和人脐静脉内皮细胞、人真皮成纤维细胞和人脐静脉内皮细胞共培养,所形成的细胞片可生成类似原生血管的管状结构。目前的组织工程细胞片的生物力学性能较差,与传统支架结合仍然存在着材料降解引起的组织纤维化和免疫排斥等问题,组织工程细胞片在牙周组织工程应用中具有较大应用前景;但是,要实现牙周组织的完全再生,其技术有待进一步的研究。本文就细胞片的构建、不同的牙周组织工程细胞片、细胞片工程面临的问题等研究进展作一综述。     

细胞膜片技术及其在种植体表面的应用进展

为了提高种植体骨结合,增加种植治疗的成功率,细胞膜片技术从生物学的角度提供了种植体表面改性的新方法。细胞膜片技术是一种保留细胞外基质、不含支架的细胞处理方法,与常规植入材料相结合可形成膜片-种植体复合体。同时越来越多的研究表明细胞膜片可以作为基因工程的载体,搭载成骨相关基因,从而促进种植体骨结合。然而,此项技术在种植体应用方面还面临着一些问题,如膜片种植体制备方法单一、体内膜片种植体存活状况未知等。因此,该文将从细胞膜片及膜片种植体的制备方法、体内细胞膜片的追踪方法等方面对其进行总结。     

组织工程细胞膜片的获取方式

细胞膜片组织工程是一种新的细胞疗法,能制作出有活性的可移植的细胞膜片并应用于组织工程。本文介绍了不同反应性系统如温度反应性系统、电反应性系统、光反应性系统、pH反应性系统、磁系统的细胞膜片形成机制、制作方式以及应用。这些系统将有助于实现细胞膜片的大量获取和复杂组织的重建。     

骨髓间充质干细胞膜片技术及应用的研究进展

骨髓间充质干细胞易于获得,贴壁生长,具备优良的成膜特性,是现代组织工程学中理想的种子细胞。由于具有良好的分化能力,骨髓间充质干细胞膜片被广泛地应用于组织再生工程。常用的骨髓间充质干细胞膜片包括单层细胞膜片、共培养细胞膜片、多层细胞膜片、三维培养细胞膜片、细胞膜片片段等。本文就近年来利用骨髓间充质干细胞构建细胞膜片的方法及其应用做如下综述。     

利用细胞膜片技术进行牙周重建的研究进展

牙周炎是人类牙齿缺失的最主要病因,危害人类口腔及全身健康。牙周再生的目标是再生牙周组织和重建功能性牙槽骨-牙周膜-牙骨质牙周复合体。随着组织工程学和牙周再生技术的发展,细胞膜片技术的出现为牙周重建提供了新思路。现就细胞膜片技术在细胞膜片构建和不同来源种子细胞两方面的研究进展作一综述。     

应用牙周膜干细胞—牙囊干细胞复合细胞膜片同种异体移植修复比格犬牙周组织缺损的研究

目的 拟构建比格犬牙周缺损模型,观察牙周膜干细胞—牙囊干细胞复合细胞膜片修复牙周组织缺损的效果.方法 分离培养比格犬牙囊干细胞、牙周膜干细胞,制备牙囊干细胞细胞膜片、牙周膜干细胞细胞膜片以及以上2种细胞的复合细胞膜片,将膜片混合支架材料同种异体植入成年雄性健康比格犬牙周缺损模型,对照组只植入支架材料.分别于移植后1周、2周、4周、6周、8周、12周检测探诊深度、牙龈退缩、附着丧失情况.12周后观察分析牙周再生的组织形态学变化.结果 牙周临床检查及组织学形态学分析显示,3个膜片移植组牙周再生效果较对照组效果明显,其中复合细胞膜片移植组明显高于其余两个单一膜片移植组(P<0.05).结论 牙周膜干细胞—牙囊干细胞复合膜片同种异体移植更有利于修复比格犬牙周缺损.     

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.     

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.     

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.     

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。     

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.     

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。     

5种着色氧化锆陶瓷的细胞毒性评价

目的：对掺杂5种微量着色剂的氧化锆陶瓷的生物安全性进行初步评价.方法：采用四氮唑盐比色法（MTT）细胞毒性评价方法,用5种着色氧化锆陶瓷材料的浸提液体外培养L929小鼠成纤维细胞2 d、4 d、7 d,于倒置相差显微镜下观察细胞形态;用MTT检测各实验组和对照组的吸光度值（OD值）,计算各组细胞的相对增殖率,并按照6级毒性分类法对各实验组进行评级.结果：培养期细胞贴壁生长,细胞形态正常.随着培养天数增加细胞大量增殖,各实验组的毒性评级为0-1级.结论：添加5种微量着色剂的氧化锆陶瓷无细胞毒性,具备体内应用的生物安全基础.