美兰和超氧化物歧化酶对变形链球菌产酸作用的影响

目的：研究美兰（methylene blue）和超氧化物歧化酶（superoxide dismutase,SOD）对变形链球菌产酸作用的影响,探讨美兰和超氧化物歧化酶用于龋病预防的可行性。方法：采用气相色谱法研究美兰及超氧化物歧化酶对变形链球菌产酸的影响作用。用乳酸脱氢酶试剂盒检测不同培养条件下变形链球菌乳酸脱氢酶活性。结果：美兰对变形链球菌产酸具有抑制作用;SOD对变形链球菌产酸没有影响;不同培养条件下变形链球菌乳酸脱氢酶活性变化不明显。结论：由于作用机理不同,美兰和超氧化物歧化酶对变形链球菌产酸的作用也不同,美兰可能成为有价值的防龋制剂。     

美兰对变形链球菌及菌斑抑制的实验研究

的　研究美兰对变形链球菌生长和产酸代谢的作用以及对体外菌斑糖酵解模型产酸代谢的作用,以探讨美兰防龋的可行性。方法　采用比浊法测定不同培养条件下变形链球菌培养液的OD值;采用气相色谱法检测不同培养条件下变形链球菌培养液中有机酸的种类和数量;测定不同处理条件下体外菌斑糖酵解模型产酸液的 pH值。结果　(1)美兰组细菌OD值低于生理盐水组,二者之间的差异具有统计学意义;(2)不同血清型变形链球菌的3个处理组中均可检测到有机酸的产生,葡萄糖组有机酸的总量最多,美兰组有机酸的总量最少;(3)美兰组产酸液的pH值与阴性对照组之间的差异有统计学意义,与阳性对照组之间的差异无统计学意义。结论　美兰可以抑制变形链球菌的生长、产酸代谢以及菌斑的产酸代谢。     

人工体外菌斑模型的建立及其在评价防龋制剂防龋效果中的应用

目的：建立人工体外菌斑模型，研究美兰和洗必泰对人工体外菌斑代谢产酸的作用，探讨用人工体外菌斑模型评价防龋制剂防龋效果的可行性。方法：采用pH计分别测定不同生长时期及美兰和洗必泰处理后人工体外菌斑模型产酸液的pH值。结果：成功建立了人工体外菌斑模型；随着该模型生长时间的延长，产酸液pH降低；随着该模型在产酸液中培养时间延长，产酸液pH逐渐降低；美兰和洗必泰对生长96h人工体外菌斑代谢产酸没有明显作用，对生长48h人工体外菌斑代谢产酸有明显抑制作用。结论：用人工体外菌斑模型评价防龋制剂的防龋效果是可行的。     

美兰抑制变形链球菌产酸的实验研究

目的　研究美兰对变形链球菌在外源性糖培养条件下产酸的抑制作用 ,探讨美兰作为一种新型防龋制剂的可行性。方法　通过将美兰加入变形链球菌糖培养液的方法 ,以不加美兰者作对照 ,用气相色谱法检测不同培养条件下变形链球菌培养液中产生有机酸的种类和数量。结果　美兰组有机酸的总量为 14.6 6± 5 .42 mmol/L,与对照组比较相差显著 (P<0 .0 1) ;其中以乳酸的量为最高 ,且均未检出丙酸和丁酸。结论　美兰具有抑制变形链球菌产酸的作用 :美兰作为防龋制剂具有一定的应用价值     

美兰对体外菌斑糖代谢模型产酸代谢的抑制作用

目的：研究美兰对体外菌斑糖酵解模型产酸代谢的影响,为美兰用于防龋临床实践提供理论依据。方法：采用改良体外菌斑糖酵解模型,以洗必泰作为阳性对照,去离子水作阴性对照,0．1g/L美兰溶液及含0．1g/L美兰的产酸液为实验组,ORION电极检测产酸液pH,并观察美兰抑制菌斑产酸的有效时间。结果：产酸液中0．1g/L美兰对体外菌斑产酸代谢具有明显的抑制作用,美兰对产酸代谢的抑制作用与浓度有关。结论：美兰可以抑制菌斑的产酸代谢,美兰抑制菌斑产酸代谢的最低有效浓度还需要研究。     

口腔微生物与免疫学

变形链球菌GbpA的GBD免疫防龋实验研究；附着状态对口腔白色念珠菌ALS基因mRNA的影响；第一恒磨牙窝沟菌群组成；c血清型变形链球菌致龋相关基因，DNA片段的批量克隆与高通量筛选；外源性糖对变形链球菌活性氧代谢的作用。     

蜂胶对变形链球菌的抑菌及粘附抑制实验

目的：测定蜂胶对变形链球菌的抑菌及粘附抑制作用效果，以探讨蜂胶防龋的机制。方法：①用不同浓度的蜂胶溶液，采用杯碟法检测晨胶溶液抑菌活性，并测出其最小抑菌浓度；②用0.04％、0.01％蜂胶溶液采用毛细管法检测蜂胶对变形链球菌粘附抑制效果，设置空白对照及2％氟化钠阳性对照。结果：①蜂胶溶液对变形链球菌有较强的抑菌作用，最小抑菌浓度为0.025％；②0.04％、0.01％两个浓度的蜂胶溶液对变形链球菌的粘附抑制作用明显高于对照组。结论：蜂胶对变形链球菌有明显的抑菌及抑制变形链球菌粘附作用，提示蜂胶具有较强的防龋效果。     

有机弱酸对变链菌产酸作用的影响

目的 探讨有机弱酸苯甲酸、苹果酸、柠檬酸对口腔主要致龋菌变形链球菌的作用，并与氟化钠进行比较；探讨上述弱酸作为防龋剂的可能性。方法 将变形链球菌Smutans Ingbritt置入含有不同浓度的氟化钠、苹果酸、柠檬酸、苯甲酸的液体培养基TSB中生长48h，测定菌液的终末pH值，推测上述弱酸对细菌产酸能力的抑制作用，结果 苯甲酸、苹果酸、柠檬酸的抑菌所需浓度较氟化钠浓度高，且具浓度依赖性。结论 氟化钠抑制变形链球菌产酸作用最好；而有机弱酸苯甲酸、苹果酸、柠檬酸在较高浓度下，才有不同程度抑制变形链球菌产酸作用，但该浓度却有可能对牙釉质产生脱矿作用。     

美兰和超氧化物歧化酶对变形链球菌生长的作用

目的 :研究美兰和超氧化物歧化酶 (SOD)对变形链球菌生长的作用 ,探讨美兰和超氧化物歧化酶用于龋病预防的可行性。方法 :采用比浊法测定有无美兰存在条件下变形链球菌的OD值 ,采用麦氏比浊法测定不同浓度SOD条件下变形链球菌的生长量。结果 :美兰对变形链球菌的生长具有抑制作用 ;不同浓度SOD对变形链球菌的生长均有促进作用。结论 :美兰及SOD均能清除氧自由基 ,但由于作用机制不同 ,二者对变形链球菌生长作用的表现不同。美兰的抑菌作用有望用于龋病预防。     

酪蛋白磷酸肽钙磷复合体对变形链球菌产酸影响的实验研究

目的 研究酪蛋白磷酸肽钙磷复合体（casein phosphopeptide-amorphic calcium phosphate，CPP-ACP）对变形链球菌产酸的影响，探讨CPP-ACP作为一种生物防龋制剂的可行性。方法 将变形链球菌加入含不同浓度CPP-ACP的蔗糖培养基中，厌氧培养48h，用精密pH计检测培养基上清液的pH值，计算pH的变化值ApH（初始pH值-终末pH值）。结果 随CPP-ACP浓度的升高，培养基上清液的pH值升高，ApH降低，即变形链球菌的产酸量降低（P〈0．01）。结论 CPP-ACP对变形链球菌产酸具有抑制作用，且随CPP-ACP浓度的升高抑制作用增强。     

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.     

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.     

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。     

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.     

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.     

《口腔医学》杂志2007年度有关信息的分析

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。     

比色板标准与非标准色标识别差异的初探

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.     

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。