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Peter Milgrom Peter Ratener Philip Weinstein 《Community dentistry and oral epidemiology》1983,11(1):33-39
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. 相似文献
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M.S. Baymak H. Celik H. Lund P. Zuman 《Journal of electroanalytical chemistry (Lausanne, Switzerland)》2005,581(2):284-293
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 dE1/2/dpH and pKa-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. 相似文献
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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. 相似文献
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《Oral Science International》2014,11(2):56-59
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. 相似文献
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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. 相似文献
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颌骨动静脉畸形的栓塞治疗 总被引:9,自引:0,他引:9
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。 相似文献
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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。 相似文献
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目的通过对《口腔医学》2007年全年文献的回顾和分析,了解我国口腔临床医学的研究现状。方法阅读2007年《口腔医学》全年的文献,对各种信息进行了分类汇总,根据设计类型对临床一次性文献进行了分类,并对其中的试验性研究文章进行质量分析。结果《口腔医学》2007年全年的一次性文献274篇,基础和临床文献分别为108和166篇,以临床文献为主(60.58%)。在临床研究文献中,属于观察性、分析性和试验性的文献分别为97、9和60篇,观察性文献所占比例为36.14%,高于以往的报道。60篇观察性文献中,全都设有对照;统计方法应用得当者44篇;真正做到随机、盲法的分别只有4和2篇。结论我国口腔临床方面的研究水平近年来提高明显,但设计的科学性方面有待提高。 相似文献
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口底癌34例临床分析 总被引:1,自引:0,他引:1
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。 相似文献
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下颌角骨折治疗后并发症的临床分析 总被引:1,自引:0,他引:1
目的研究下颌角骨折治疗后并发症,分析原因并提出预防方法。方法回顾分析我院206例下颌角骨折患者的治疗及并发症情况,分颌间固定组62例,内固定组120例,颅颌绷带组24例。结果治疗后发生的并发症有骨感染4例,医源性损伤2例,牙合干扰3例,错牙合畸形2例,颞下颌关节功能紊乱病2例。结论下颌角骨折的治疗应首选坚强内固定,应选择正确的手术方案,加强术前、术后抗感染治疗及术后肌功能训练,对骨折线上的阻生齿应尽可能保留,以减少并发症。 相似文献
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Influence of the quality of life and locus of control of mothers of disabled children on the oral health of their children
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Raquel Maria de Castro Soares de Barros Rosana de Fátima Possobon Estêvão Azevedo Melo Livia Fernandes Probst Luciane Miranda Guerra Karine Laura Cortellazzi Gláucia Maria Bovi Ambrosano 《Special care in dentistry》2017,37(6):290-298
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目的 测试口腔修复学专业研究生对比色板标准色标与非标准色标颜色识别的差异,评价、分析口腔修复学专业研究生临床实际比色能力,为探讨临床比色教学方法提供客观的基础数据.方法 选择具有1~5年临床工作经验、排除色觉识别障碍、经过色彩学知识培训的口腔修复学专业研究生62名.从比色板A(Lineargnide)的29个标准色标中通过随机数字表抽取7个色标作为标准色标,以比色板B(Vita Bleachadgnide 3D-Master)中的7个色标作为非标准色标,在D55标准光源下,以比色板C(Vita 3D-Master)作为比色工具,对标准色标和非标准色标进行比色测试.计算受试者对两种色标比色的总体准确率;统计比色正确的人数分布,并进行Monte Carlo确切概率法检验;统计比色结果在明度、饱和度、色相上的等级偏差,并进行Wilcoxin符号秩和检验.结果 受试者对标准色标比色的总体正确率为45.9%(199/434),对非标准色标比色的总体正确率为9.0%(39/434);对两种色标比色正确的人数分布的差异有统计学意义(P<0.001);对两种色标比色结果的明度等级偏差[分别为0.2(0.1~0.3)、0.4(0.4~0.5)]、饱和度等级偏差[分别为0.2(0.1~0.4)、0.5(0.4~0.6)]的差异均有统计学意义(P<0.01),色相等级偏差[分别为0.3(0.1~0.4)、0.3(0.1~0.4)]的差异无统计学意义(P=0.079>0.01).结论 口腔修复学专业研究生对比色板非标准色标颜色的识别能力明显低于对标准色标颜色的识别能力. 相似文献
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S. Rifai M. Laferrière D. Qu D.D.M. Wayner C.P. Wilde M. Morin 《Journal of electroanalytical chemistry (Lausanne, Switzerland)》2002,531(2):111-118
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. 相似文献
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目的 了解牙龈瓷的颜色再现受瓷层厚度影响的变化规律。方法 采用分光光度计(PR-650)测量不同厚
度Shofu vintage pink龈色瓷,不同厚度牙本质瓷及不同颜色的遮色瓷和牙本质瓷对金瓷试件颜色改变的影响。结果
当Shofu vintage pink龈色瓷厚度从0·3 mm增加到0·9 mm,金瓷试件的L*值不断降低,a*值不断升高;牙本质瓷
厚度的增加使试件颜色向亮度低,偏红方向变化;不同颜色遮色瓷、牙本质瓷层厚度会导致龈色瓷表面的颜色改
变。结论 瓷层厚度可以影响牙龈瓷的颜色再现。 相似文献
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连续波热牙胶充填技术根尖封闭性能的评估 总被引:3,自引:1,他引:2
目的体外实验比较不同器械预备根管后连续波热牙胶根管充填技术的根尖封闭能力。方法离体双根管上颌前磨牙随机分为机用ProFile预备组和不锈钢K锉预备组,分别采用连续波热牙胶充填技术和冷侧压法进行根管充填,用染料渗透法和透明标本法测量根尖微渗漏,评价各组根尖封闭能力。结果各组根尖微渗漏距离无统计学差异(P>0.05)。结论连续波热牙胶充填技术与冷牙胶侧方加压充填技术的根尖封闭能力无显著性差异;对直根管和轻度弯曲的根管,不同器械根管预备后其根管充填效果无明显影响。 相似文献