钛表面预氧处理对钛瓷结合强度的影响

目的探讨钛表面预氧化处理对钛/瓷结合强度的影响。方法分别对未经预氧化处理的钛表面和预氧化处理的钛表面进行表面粗糙度、表面接触角测试;然后根据ISO96931990标准,对钛与Noritake Super Ti-22钛瓷间的三点弯曲结合强度进行测试,并对钛/瓷结合界面进行扫描电镜观察。结果预氧化组的钛表面粗糙度小于未预氧化组(P<0.05),接触角也明显小于未预氧化组(P<0.01)。预氧化组的钛/瓷结合强度大于未预氧化组(P<0.05)。预氧化组钛/瓷界面瓷与钛基体相互交错,结合紧密,无明显气泡;而未预氧化组钛/瓷界面存在着较多的孔隙。结论钛表面预氧化可有效地提高钛/Noritake SuperTi-22钛瓷的结合强度。     

钛表面微弧氧化处理对钛瓷结合强度的影响

目的:探讨微弧氧化膜作为钛与瓷间的中间层,增强钛瓷结合强度的可行性。方法:对钛表面采用打磨光滑、喷砂处理、微弧氧化等 3种不同方法进行处理后,表面进行瓷粉烧结。根据ISO9693标准,对钛瓷间的三点弯曲结合强度进行测试,并对钛瓷结合界面和瓷剥脱面进行SEM和EDX观察与分析。以镍铬合金与瓷的结合强度测试结果为对照。结果:微弧氧化组的钛瓷结合强度与镍铬合金瓷组相比在统计学上无显著差异(P>0. 05);粗糙组的钛瓷结合强度大于光滑组(P<0. 05),但明显小于微弧氧化组 (P<0. 01)。光滑组的钛瓷界面间可见有约 25μm的裂隙;粗糙组的钛瓷界面只有在局部区域存在着少量的孔隙;而微弧氧化组的钛瓷界面瓷与钛基体结合紧密,无任何气泡、孔隙存在。结论:钛表面微弧氧化可有效地提高钛瓷的结合强度,达到镍铬合金与瓷的结合强度水平。     

4种纯钛专用瓷粉对钛瓷结合强度的影响

目的：探讨4种钛瓷粉对钛瓷结合强度的影响。方法：分析Super Ti22、Duceratin、Titankermik、Ti-bond4种钛瓷粉的化学组成和瓷粉粒度,制备4种瓷粉的钛瓷试件并利用三点弯曲测试其钛瓷结合强度。利用电镜观察各组钛瓷结合界面并进行元素分析。结果：4种瓷粉粒度分布不均,化学成分差异较大。4种瓷粉钛瓷结合强度均达到IS09693标准,其中Super Ti22、Duceratin瓷粉钛瓷结合强度明显高于另2组（P〈0．05）。电镜观察,Super Ti22组和Duceratin组钛瓷结合紧密,无明显孔隙出现,其余2组可见明显孔隙。结论：Super Ti22、Duceratin瓷粉更有利于钛瓷结合。     

3种粘接瓷对钛瓷结合强度的影响

目的:观察3 种粘接瓷对钛瓷结合强度的影响,分析粘接瓷作用机制.方法:将纯钛试件随机分为3 组分别采用纯钛专用瓷Super Ti22,Duceratin,Titankeramik进行烧结,每种瓷粉又分为涂布粘接瓷组和未涂布粘接瓷组,共6 组.根据ISO9693标准,运用三点弯曲方法测试各组钛瓷结合强度.对钛瓷结合界面进行扫描电镜观察和能谱分析.结果:Super Ti22涂布粘接瓷组结合强度为(35.84±2.17) MPa,Duceratin涂布粘接瓷组结合强度为(35.45±2.37) MPa,均显著大于各自未涂布组(P<0.05);Titankeramik涂布粘接瓷组结合强度为(31.73±1.66) MPa, 略大于其未涂布组(29.86±2.48) MPa,但差异无显著性(P>0.05).电镜观察Super Ti22和Duceratin涂布粘接瓷组钛瓷结合界面结合紧密,未见明显孔隙出现;其余各组均可见明显孔隙.结论:粘接瓷的应用有利于钛瓷结合强度的提高.     

纯钛烤瓷中微弧氧化处理的实验研究

目的:探讨微弧氧化处理应用对钛与瓷的结合强度的影响,摸索微弧氧化处理的适宜条件.方法:对钛表面进行喷砂、抛光、喷砂加微弧氧化处理和抛光加微弧氧化处理后,分为4组表面进行纯瓷粉烧结.根据ISO 9693标准,对钛瓷间的三点弯曲结合强度进行测试.镍铬合金与瓷的结合强度测试结果为对照.结果:粗糙面微弧氧化组钛瓷结合强度(45.84±3.15MPa)与NiCr/VITA 99组的结合强度(48.35±3.06MPa)相比,在统计学上无显著差异(P0.05),却明显大于粗糙而组的结合强度(36.12±3.03MPa)(P<0.05);光滑面组钛/瓷结合强度(30.79±1.43MPa)明显小于粗糙面组光滑面组(P<0.01),但大于光滑面微弧氧化组(24.12±3.38MPa)(P<0.05).结论:纯钛表面喷砂后进行微弧氧化处理,可有效地提高钛瓷的结合强度.     

钛表面预处理对钛-瓷剪切结合强度影响的研究

目的　探讨不同的钛表面预处理对自制新型镧系低熔瓷的钛-瓷结合强度的影响,为自行研制钛瓷瓷粉体的临床应用奠定理论基础。方法　钛表面分别经不同粒度的Al2O3喷砂粗化、偶联剂处理及预氧化处理;制作棒、盘试件,用压出法测试钛-瓷间的剪切结合强度,用扫描电子显微镜(SEM)及电子探针(EPMA),从微观和相关元素方面观察钛-瓷界面。结果　80~250μm 5种不同粒度的Al2O3喷砂处理钛表面后,对钛-瓷剪切结合强度无明显影响;自制硅偶联剂使剪切结合强度降低;钛表面预氧处理对剪切结合强度无明显影响。结论　镧系低熔瓷对钛表面具有良好的湿润性;钛金属表面硅偶联剂处理或预氧化处理是不必要的;在一定范围内,剪切结合强度受钛表面粗糙度的影响较小。     

磁控溅射氮化铌对钛-瓷结合强度的影响

目的 探讨磁控溅射氮化铌(niobium nitride,NbN)对钛-瓷(Vita钛瓷粉系统)结合强度的影响,以期为钛-瓷修复体的临床应用提供参考.方法 根据随机数字表将60个钛试件随机分为T1、T2、T3和T4四个实验组.T1和T2组试件表面均先行120μm Al2O3喷砂,T2组试件表面再行磁控溅射氮化铌涂层.T3和T4组试件表面均先行磁控溅射氮化铌涂层,T4组试件表面再行120μmAl2O3喷砂.X射线衍射分析仪(X-ray diffraction,XRD)分析各组涂层物相.试件烤瓷后用万能实验机测试钛-瓷结合强度.扫描电子显微镜-X射线能谱仪(scanning electron microscopy with energy depressive spectrum,SEM-EDS)观察和分析钛-瓷结合界面.结果 XRD观察到T2、T3和T4组均存在立方晶型的氮化铌新相.三点弯曲实验测得T1-T4组试件的钛-瓷结合强度分别为(27.2±0.8)、(43.1±0.6)、(31.4±1.0)和(44.9±0.6)Mpa,4组间差异有统计学意义(P<0.05).两两比较显示,任意两组间差异均有统计学意义(P<0.05).SEM观察T1和T3组钛-瓷结合界面可见明显孔隙和裂纹,T2和T4组钛-瓷结合较好,EDS线扫描显示,T1组钛基底氧化明显,T2组和T3组界面处存在钛氧化行为,T4组界面处钛基底的氧化得到抑制.结论 磁控溅射氮化铌可抑制烤瓷侧钛基底的氧化,提高钛-瓷结合强度,同时表明Al2O3喷砂处理也能提高钛-瓷结合强度.     

钛表面不同喷砂条件处理对钛/瓷结合强度的影响

目的探讨钛表面采用不同喷砂条件进行处理对钛/瓷结合强度的影响,为临床操作提供依据。方法采用50μm和250μm的Al2O3分别在0.2MPa、0.4MPa的压力下对钛表面进行喷砂粗化处理后,通过电镜观察Al2O3颗粒在钛表面残留量,并对钛表面粗糙度、钛表面接触角以及钛瓷间的结合强度进行检测,确定喷砂条件对钛/瓷结合强度的影响。结果50μm、0.4MPa组的钛试件表面的Al2O3颗粒残留较多。喷砂压力相同时,250μmAl2O3喷砂处理的钛表面粗糙度较大(P<0.05);喷砂粒度相同时,0.4MPa喷砂压力下的钛表面粗糙度较大(P<0.05)。喷砂压力相同时,250μmAl2O3喷砂处理的钛表面接触角较大(P<0.05);喷砂粒度相同时,钛表面接触角无统计学差异(P>0.05)。统计分析显示250μm、0.4MPa组的钛/瓷结合强度最大(P<0.05);50μm、0.4MPa组的钛/瓷结合强度最小(P<0.05);50μm、0.2MPa组和250μm、0.2MPa组的钛/瓷结合强度无显著差异(P>0.05)。结论在0.2MPa压力下进行喷砂处理时,采用50μm和250μm的Al2O3颗粒对钛基体进行喷砂处理均可。在0.4MPa的压力下对钛表面进行喷砂处理时应采用较大粒度的Al2O3颗粒。     

表面处理对两种钛瓷粉的钛瓷结合力的影响

目的:研究不同表面处理方法及不同钛瓷粉对钛瓷结合力的影响,以寻找合理有效的钛表面处理方法及适合临床应用的钛瓷粉,为临床钛烤瓷修复体的制作和应用提供理论依据。方法:本实验根据ISO9693标准中三点弯曲法制作试件,试件随机分3组,每组14个,分别采用600目砂纸打磨、打磨 喷砂及打磨 喷砂 酸洗的表面处理方法后,在试件中部烤瓷,测试结合强度并对钛瓷结合界面进行扫描电镜观察,将结果与Ni-Cr合金组进行比较。结果:经过喷砂和喷砂酸洗后,Ti22瓷粉与钛的结合强度为(28.58±1.25)MPa和(31.39±5.87)MPa,Vita Titankeramik瓷粉与钛的结合强度为(26.57±4.04)MPa和(29.66±1.12)MPa,显著高于打磨组的(19.55±0.37)MPa和(20.94±1.10)MPa(P<0.05),喷砂与喷砂酸洗组之间无统计学差异。两种瓷粉间无统计学差异(P>0.05)。经过喷砂及喷砂处理的各组结合强度均达到ISO9693临床标准(>25MPa)。但与普通烤瓷对照组比较,钛瓷结合力显著小于普通烤瓷结合力。结论:喷砂及喷砂酸洗能有效增强钛瓷结合力,满足临床应用要求。     

钛表面烤瓷的预氧化处理工艺研究

目的：考察预氧化处理工艺是否适合钛－瓷修复。方法：采用剪切实验法测试在未预氧化处理（Ｒ１），３００℃（Ｒ２）、５００℃（Ｒ３）及７００℃（Ｒ４）预氧化处理时钛－氧化处理时钛－瓷结合强度，并用金、相显微镜及电子探针分析各组的钛－瓷界面状况。结果：Ｒ１、Ｒ２、Ｒ３及Ｒ４各组剪切强度值分别为５０．２５±６．５２ＭＰａ、４４．６７±７．０８ＭＰａ、２７．６９±５．２７ＭＰａ和２２．５１±４．９０Ｍｐａ。界面分析表明，各组钛与瓷界面结合紧密、无裂隙，并存在元素扩散带，不同的是各组元素扩散带宽度不一，其规律是Ｒ１＜Ｒ２＜Ｒ３＜Ｒ４。结论：预氧化处理工艺不适合钛－瓷修复。     

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