填料含量对实验双固化树脂水门汀与纤维桩黏结强度的影响

目的:比较二氧化硅填料含量对EAM树脂材料黏结性能的影响,为研制纤维桩树脂核修复材料奠定基础.方法:根据二氧化硅填料在EAM树脂中添加含量的不同分为4组(A组:40%、B组:50%、C组:60%、D组:70%),E组(对照组)LuxaCore-Dual树脂,将各组树脂水门汀在圆筒形模具内分别与纤维桩黏结后,制备成微拉伸试件.用微拉伸试验机进行拉伸,直至试件破坏,并作统计学处理.结果:4个不同二氧化硅无机填料组的微拉伸强度分别为:A组(10.15±2.72)MPa,B组(11.48±2.81)MPa,C组(12.03±2.78)MPa,D组(10.07±2.06)MPa,E组(10.88±2.85)MPa,B、C两组的黏结强度显著高于A、D、E组(P<0.05).结论:60%左右无机填料含量的复合树脂微拉伸黏结强度较为理想.     

无机填料含量对流动树脂挠曲强度和压缩强度影响体外研究

目的 研究无机填料含量对流动树脂的挠曲强度和压缩强度的影响。方法 于2012年4月在北京大学口腔医学院口腔材料研究室测定Clearfil Flow、Filtek Flow、DenFil Flow、Filtek Z250复合树脂无机填料的质量分数、挠曲强度和压缩强度。结果 流动树脂中无机填料的质量分数与其挠曲强度的变化顺序相一致,由小到大依次为DenFil Flow、Filtek Flow、Clearfil Flow、Filtek Z250。DenFil Flow与其余3组间挠曲强度差异均有统计学意义（P < 0.05）,Filtek Flow与Clearfil Flow、Filtek Z250间挠曲强度差异亦均有统计学意义（P＜0.05）,但Clearfil Flow与Filtek Z250间挠曲强度差异无统计学意义（P＞0.05）。4种材料压缩强度差异均无统计学意义（P＞0.05）。结论 高填料型流动树脂的挠曲强度远高于普通流动树脂,并且可达到我国医药行业标准规定牙合面修复材料的要求;压缩强度与前后牙通用树脂相近,可以满足临床应用的需要。     

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目的研究无机填料含量对流动树脂的挠曲强度和压缩强度的影响。方法于2012年4月在北京大学口腔医学院口腔材料研究室测定Clearfil Flow、Filtek Flow、DenFil Flow、Filtek Z250复合树脂无机填料的质量分数、挠曲强度和压缩强度。结果流动树脂中无机填料的质量分数与其挠曲强度的变化顺序相一致,由小到大依次为DenFil Flow、Filtek Flow、Clearfil Flow、Filtek Z250。DenFil Flow与其余3组间挠曲强度差异均有统计学意义（P〈0.05）,Filtek Flow与Clearfil Flow、Filtek Z250间挠曲强度差异亦均有统计学意义（P〈0.05）,但Clearfil Flow与Filtek Z250间挠曲强度差异无统计学意义（P〉0.05）。4种材料压缩强度差异均无统计学意义（P〉0.05）。结论高填料型流动树脂的挠曲强度远高于普通流动树脂,并且可达到我国医药行业标准规定面修复材料的要求;压缩强度与前后牙通用树脂相近,可以满足临床应用的需要。     

CGF—1型复合体的物理机械性能

目的：评价研制的新型光固化复合体ＣＧＦ－１与Ｄｙｒａｃｔ复合体、ＣＯ－１和ＦＵＪＩⅡ玻璃离子水门汀的物理机械性能。方法：按照有关实验方法分别测试研制复合体与对照材料的压缩强度、径向拉伸强度、挠曲强度、表面硬度。结果：ＣＧＦ－１的ＣＳ、ＤＴＳ、ＦＳ值都明显高于ＣＯ－１、ＦＵＪＩⅡ，接近Ｄｙｒａｃｔ。结论：ＣＧＦ－１型复合体的机械强度明显高于玻璃离子，可用作直接充填修复材料     

纳米金刚石改性核树脂的机械及固化性能

目的以纳米金刚石（ UFD）为填料加入到自行合成的光固化核树脂中,测试核树脂的性能变化。方法将不同含量的钡玻璃粉填料和UFD加入到树脂基质中制得6组光固化核树脂,分别测试它们的挠曲强度、维氏显微硬度和光固化深度,使用单因素方差分析法对挠曲强度、维氏显微硬度值的测量结果进行统计学分析。结果仅加质量分数为0.2%硅烷化处理的UFD即可使钡玻璃含量分别为60%和70%的两种光固化核树脂的挠曲强度分别提高34%和21%,而维氏显微硬度分别增加23%和30%;同时核树脂的固化深度均超过2 mm,符合相应的国际标准要求。但是UFD会对核树脂的颜色产生一定影响。结论微量UFD的加入能显著改善树脂的机械性能,同时又不影响材料的固化性能,但是对树脂颜色的影响需进一步改善。     

氧化锌晶须增韧复合树脂的制备及机械性能的研究

目的:考察含氧化锌晶须复合填料对牙科复合树脂机械性能的影响。方法:采用机械共混法制备含氧化锌晶须、纳米二氧化硅填料复合树脂,SEM观察其表面形貌和分散情况,并考察表面处理的氧化锌晶须复合填料对复合树脂的挠曲强度、压缩强度和挠曲弹性模量的影响。结果:氧化锌晶须复合填料添加比为70%时复合树脂的综合力学性能最好,其挠曲强度、压缩强度和挠曲弹性模量分别为(87.16±2.86)MPa、(156.61±7.62)MPa和(2.32±0.17)GPa。结论:氧化锌晶须复合填料的加入能改善牙科复合树脂的机械性能,满足临床使用要求。     

纳米增韧牙科复合树脂的研究

目的：研究纳米二氧化锆、纳米金刚石为功能填料加入到以钡玻璃粉为主填料的光固化牙科复合树脂中,观察树脂挠曲强度的变化.方法：采用双酚A-甲基丙烯酸缩水甘油酯（Bis-GMA）和二甲基丙烯酸三甘醇酯（TEGDMA）为树脂基质,钡玻璃粉（BG）为主填料,选择纳米二氧化锆,纳米金刚石为功能填料,采用原位聚合法生成光固化牙科树脂,万能材料试验机测试其挠曲强度.结果：纳米二氧化锆和纳米金刚石之间不存在交互效应.不同浓度纳米二氧化锆之间有显著差异,不含纳米二氧化锆的树脂挠曲强度显著高于含5%纳米二氧化锆树脂的挠曲强度.不同浓度纳米金刚石之间有显著差异,含0.2%纳米金刚石的树脂挠曲强度显著高于含0.1%纳米金刚石树脂的挠曲强度.结论：含5%纳米二氧化锆、0.2%纳米金刚石的复合树脂颜色美观,其挠曲强度能达到相应的国家标准及ISO标准,能满足临床需要.     

硼酸铝晶须对不同树脂体系实验复合树脂力学性能的作用

目的：评价硼酸铝晶须对不同树脂体系实验复合树脂力学性能的作用。方法：采用四种基质树脂和两种稀释单体，按照有关实验方法测试各种实验复合树脂的表面硬度（Ｈｖ）、径向拉伸强度（ＤＴＳ）和压缩强度（ＣＳ）。结果：晶须组的机械性能优于对照组，表面硬度（Ｈｖ）对照组高于晶须组。结论：晶须对复合树脂的ＣＳ、ＤＴＳ有明显增强作用；ＰＵ基质树脂组的力学性能明显优于其它实验组（Ｐ＜０．０１）。     

5种后牙光固化复合树脂的三种性能测试

用可见光照射Ｚ１００、ＥｓｔｉｏＬＣ、Ｈｅｌｉｏｍｏｌａｒ、Ｏｃｃｌｕｓｉｎ、Ｌｉｔｅ－ＦｉｌⅡ５种复合树脂。通过测定其压缩强度、径向拉伸强度及表面硬度，研究５种不同的光固化材料的某些机械性能的差异。实验结果表明：不同的光固化材料，其压缩强度、径向拉伸强度及表面硬度均有差异。Ｏｃｃｌｕｓｉｎ、Ｚ１００、Ｌｉｔｅ－ＦｉｌⅡ３种后牙复合树脂物理机械性能较好，而适用于前后牙的Ｈｅｌｉｏｍｏｌａｒ、ＥｓｔｉｏＬＣ则较差     

四种树脂磨耗性能的体外研究

目的 研究四种常用复合树脂与牙釉质磨损的规律和状态以及硬度与磨损量的关系.方法 利用UMT-2微摩擦磨损实验机模拟口腔咀嚼状态.应用称重法计算磨损量,测试树脂硬度值,扫描电镜观察磨损表面形貌.结果 SEM显示,B,S树脂中无机填料颗粒体积较大,T树脂次之,K树脂相对较小且均匀.四种树脂无机填料颗粒周围均出现裂纹和脱落迹象.K树脂磨损面可见清晰的划痕走向;T,B,S树脂磨损为不等量磨损.K为等量均匀磨损;四种树脂的耐磨性与硬度关系,P>0.05.结论 无机填料细小而且混合较均匀的复合树脂,磨损状态趋于等量磨损,无机填料颗粒大小不均匀的复合树脂磨损状态为不等量磨损;复合树脂耐磨性与树脂硬度问没有直接关系;对于不同的临床需要.应该选择不同类型的复合树脂料.     

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