微弧氧化电压处理钛表面后对钛瓷结合强度的影响

目的：观察钛试样在微弧氧化处理过程中,电源电压不同,形成的氧化膜对钛瓷结合强度的影响。方法：电解液由去离子水和Na2SiO3溶液组成,占空比和频率为0．04、500Hz,时间3min,电压分别为Ⅰ组300V;Ⅱ组350V;Ⅲ组400V,分别对钛试样表面进行处理,扫描电镜（SEM）观察膜表面形貌;对不同组别试件进行瓷粉烧结,再采用三点弯曲试验测量钛与瓷的结合强度。结果：随电压的升高,钛试件表面形貌变化较大,微孔直径增大,微孔的数量明显减少,表面变得粗糙不平,氧化膜的厚度也随之增加,从5μm增加到10μm;钛与瓷的结合强度随电压增大逐渐降低,但微弧氧化组的结合强度明显高于未行微弧氧化组（P〈0.01）。结论：钛在烤瓷前经微弧氧化处理有利于钛与瓷的结合,且微弧氧化过程中不同处理电压对钛瓷结合强度有影响。     

微弧氧化中不同浓度Na_2SiO_3溶液对钛-瓷结合强度的影响

目的:研究以不同浓度Na_2SiO_3溶液进行微弧氧化处理后对钛-瓷结合强度的影响,方法:在瓷粉烧结前,分别用3 种浓度的Na_2SiO_3溶液对纯钛片进行微弧氧化处理,瓷粉烧结后通过三点弯曲实验检测钛-瓷结合强度,并以扫描电镜(SEM)和能谱分析(EDS)对膜层表面及钛-瓷界面进行分析.结果:三点弯曲实验结果显示微弧氧化各组钛-瓷结合强度均高于对照组,当Na_2SiO_3溶液浓度为20 g/L时钛-瓷结合强度明显高于30 g/L组和40 g/L组(P<0.05).EDS分析显示经微弧氧化处理后,钛表面生成含Si元素氧化膜,其含量随溶液浓度增加而升高.扫描电镜显示,随着溶液浓度增加,氧化膜表面孔洞直径增加,氧化膜变厚,致密性下降;钛-瓷结合界面出现微小裂隙.结论:微弧氧化处理可提高钛-瓷结合强度,微弧氧化溶液浓度对钛-瓷结合强度有影响.     

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。     

微弧氧化技术提高钛-瓷结合强度的研究进展

微弧氧化(MAO)技术能够在纯钛表面形成表层多孔而内层致密的氧化陶瓷膜层,影响钛-瓷结合强度.通过优化MAO技术中电压、占空比、电流强度及氧化时间等工艺参数和电解液配方,可对纯钛表面氧化膜层的成分及结构进行改造,使其在一定程度上对钛的高温氧化性进行控制,进而达到提高钛瓷间结合强度的目的.本文重点就MAO技术提高纯钛与瓷粉之间结合强度研究进展作一综述.     

处理时间对纯钛表面微弧氧化膜结构和特性的影响

目的研究不同处理时间对纯钛表面微弧氧化膜结构和特性的影响。方法根据处理时间将纯钛试件分成10、20、30和40 min共4组,通过微弧氧化技术制备纯钛表面氧化膜。使用扫描电镜(SEM)检测氧化膜的表面及横断面形貌,X射线能谱仪(EDS)检测氧化膜的元素成分,X射线衍射仪(XRD)检测氧化膜的晶相结构。结果微弧氧化处理后,钛表面形成微孔结构的氧化膜。10 min试样膜层厚度10μm,20 min、30 min和40 min试样的膜层厚度均达20μm。各处理时间组间的膜层Ca、P含量的差异无统计学意义(P>0.05)。微弧氧化膜的主要成分是金红石、锐钛矿和羟基磷灰石。结论利用微弧氧化技术在纯钛表面形成含羟基磷灰石的多孔氧化膜,在10⁴0 min处理时间内氧化膜的Ca、P含量与处理时间无关。     

钛表面3种不同处理方法对钛-瓷结合影响的对比研究

目的对比钛表面分别经微弧氧化和Nd:YAG激光处理、喷砂处理后的表面形貌、理化性能的差异,比较其对钛瓷结合强度的影响。方法将60个规格为25.0 mm×5.0 mm×0.5 mm的标准钛片试件,随机均分为3组,每组20片(A组为微弧氧化组,B组为激光轰击组,C组为喷砂组),运用扫描电镜、X射线衍射仪、EDS等分析其形貌和物相;三点弯曲实验测试钛瓷结合强度并进行统计学分析比较。结果 A、B、C 3组试件的钛瓷结合强度均高于ISO9693要求的25 MPa,Nd:YAG激光处理试件钛瓷结合强度较微弧氧化处理高,且两者均高于喷砂组。结论 3种处理方式都能提高钛表面的钛瓷结合强度,Nd:YAG激光处理后效果优于微弧氧化和喷砂处理。     

钛表面微弧氧化处理时间对成纤维细胞铺展行为的影响

目的:研究微弧氧化处理时间对细胞铺展行为的影响.方法:应用微弧氧化电源在纯钛表面制备微弧氧化膜,应用表面粗糙度轮廓仪检测不同处理时间膜层表面的粗糙度,利用扫描电镜观察膜层的形貌特点和细胞的铺展行为.采用SPSS11.5软件包对数据进行统计学分析.结果:在一定范围内,微弧氧化处理时间越长,纯钛表面生成的氧化膜中的微孔数量越少,孔径越大,粗糙度越大.与未经处理的纯钛试样相比,微弧氧化处理后膜层更有利于细胞的黏附和铺展,但不同处理时间的膜层对细胞的铺展行为无显著影响.结论:经微弧氧化技术处理后,钛表面的粗糙度明显提高,有利于细胞的黏附与铺展.     

纯钛表面微弧氧化膜在模拟体液中的腐蚀行为

目的:研究在人工模拟体液中,纯钛表面微弧氧化膜的耐腐蚀性能。方法:在纯钛表面制备微弧氧化膜,利用扫描电镜、X射线衍射仪、表面粗糙度轮廓仪和电化学方法,分别观察其形貌特点、晶相结构、表面粗糙度,并测定其极化曲线。采用SPSS11.0软件包进行单因素方差分析。结果:微弧氧化处理后,纯钛表面生成微孔结构的氧化膜,微孔似火山丘状,直径约0.1～5μm。X射线衍射分析表明,膜层中含有金红石型、锐钛矿型二氧化钛及少量羟基磷灰石。微弧氧化后,试样表面粗糙度增加,轮廓算术平均偏差值(Ra)分别为(0.358±0.063)μm和(2.493±0.107)μm,微观不平十点高度值(Rz)分别为(2.662±0.628)μm和(16.519±1.028)μm。电化学实验表明,微弧氧化处理前后试样的自腐蚀电位、自腐蚀电流密度分别为-0.358V、0.55μA/cm2和-0.255V、0.80μA/cm2。结论:经微弧氧化技术处理后,纯钛表面形成微孔结构的二氧化钛膜层,表面粗糙度增加。在模拟体液中,钛的耐腐蚀性能明显提高。     

降温速率对Noritake瓷与铸钛结合强度的影响

目的:探讨烤瓷烧结过程中降温速率对钛铸件与瓷结合强度的影响.方法:根据ISO 9693标准制作钛烤瓷试件,分别采用15、40、50、100℃/min 4种不同的降温速率对钛烤瓷试样进行冷却,应用三点弯曲法测试钛/瓷结合强度,扫描电镜及能谱分析(SEM/EDS)观察钛表面瓷的残留量.结果:降温速率为15℃/min时的钛/瓷结合强度明显高于其他3组(P<0.01),降温速率为40℃C/min和50℃/min时2组之间的钛/瓷结合强度在统计学上无明显差异(P>0.05).降温速率为100℃/min时钛/瓷结合强度明显低于其他3组的钛/瓷结合强度(P<0.01).SEM/EDS显示降温速率越快,钛表面残留瓷越少.结论:烤瓷熔附时,慢速降温可以有效提高钛/Noritake瓷的结合强度.     

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。