The effect of plaque control and root debridement in molar teeth

The healing response of non-molar sites, molar flat surface sites, and molar furcation sites was investigated in 19 adult periodontitis patients following a periodontal therapy of plaque control and root debridement. A total of 2472 sites were monitored by recordings of dental plaque, bleeding on probing, probing depth, and probing attachment levels every 3rd month for 24 months. The results demonstrated that in sites with initial probing depth of 4.0 mm or greater, molar furcation sites responded less favorably to the therapy as compared to molar flat surface sites or non-molar sites. This was demonstrated by higher mean scores for bleeding on probing, less reduction in probing depth, and a mean loss of probing attachment of 0.5 mm over 24 months. Site analyses using linear regression showed a higher % of deeper sites with probing attachment loss for the molar furcations than either molar flat surface or non-molar sites. Among sites initially 7.0 mm or deeper, 21% of molar furcations were identified as showing probing attachment loss as compared to 7% of the molar flat surface sites and 11% of the non-molar sites.     

Enzyme histochemical studies of senile plaques and the plaque-like degeneration of arteries and capillaries (Scholz)

Summary Enzyme histochemical studies, of senile plaques and the plaque-like degeneration of arteries and capillaries (Scholz), were carried out on four brains of patients senile dementia. The NAD-diaphorese activity of the plaques increased, especially in their peripheral zones whereas the central cores showed no enzyme activity. The acid phosphatase activity of senile plaques increased markedly throughout. NAD-d and acid-ph activity in glia cells in the surrounding tissue of the plaques increased markedly. The plaques with a few exceptions showed no acetylcholinesterase activity. The plaque-like degeneration of arteries and capillaries like the central cores of plaques generally showed no NAD-d activity. Acid-ph activity in the degenerated arteries was very weak, suggesting independent amyloid deposition there. Similarity of electronmicroscopic structural and enzymatic findings in the plaques and in Wallerian degeneration (Suzuki and Terry, 1967) and the independent deposition of amyloid in the plaque-like degenerated arteries in the brain, as well as in those of internal organs, suggest that the plaques are formed by severance of neuronal continuity, by the deposition of amyloid, and that amyloid deposition is important in the pathogenesis of senile dementia.

---

Zusammenfassung Enzymhistochemische Untersuchungen an senilen Plaques und an drusiger Entartung der Arterien und Capillaren (Scholz) werden an Hand von vier Gehirnen senil Dementer ausgeführt. Die NAD-d-Aktivität der Plaques ist besonders an ihrer Peripherie gesteigert; jedoch zeigen die Kerne der Plaques keine NAD-d-Aktivität. Die saure Phosphatase-Aktivität der Plaques ist im ganzen auffallend gesteigert. Die NAD-d und saure ph-Aktivität der Gliazellen ist in der Umgebung des Plaques gesteigert. Die Plaques zeigen mit wenigen Ausnahmen keine Acetylcholinesterase-Aktivität. Die drusige Entartung der Arterien und Capillaren zeigt ebenso wie die Kerne der Plaques keine NAD-d-Aktivität. Die saure ph-Aktivität der degenerierten Wände der Arterien ist sehr schwach, was auf die selbständige Ablagerung von Amyolid hinweist. Aus der Ähnlichkeit der strukturellen und enzymatischen Befunde der Plaques mit denjenigen der Wallerschen Degenerationen in elektronenmikroskopischen Untersuchungen, und aus der selbständigen Natur der Amyloidablagerung an den drusig entarteten Wänden der Arterien im Gehirn sowie in den Körperorganen zieht der Autor den Schluß, daß die Plaques in der Gehirnrinde in der Folge von Kompression der Neuronenfortsätze durch Amyloidablagerungen gebildet werden und daß die Amyloidablagerungen in der Pathogenese der senile Dementia von Wichtigkeit sind.

     

Clinical and microbiological effects of local chlorhexidine applications

AIM: To study the effects of an application of chlorhexidine varnish (40%) on dental plaque. DESIGN: Randomised controlled clinical trial. SUBJECTS: 40 patients (50% females), aged 25-34 years after undergoing any necessary restorative treatment. Exactly one half of these individuals practiced good oral hygiene, the efforts of the others were poor. METHOD: Test groups received a chlorhexidine varnish application, the control group received a placebo varnish. Initially and after 2 and 6 weeks, a modified Dentocult SM-test, bleeding on probing, and a plaque index (Quigley-Hein) were recorded. RESULTS: In contrast to the control group, improvements in plaque index and bleeding on probing scores were found in patients with poor oral hygiene. The results of the Dentocult SM-tests showed a considerable reduction of streptococcus colonisation. The test group with good oral hygiene showed only slight improvement of the examined indices after chlorhexidine application. The index parameters of all patients of the placebo groups remained unchanged over the examination time period. CONCLUSION: The application of a chlorhexidine varnish reduced the quantity of the Streptococcus mutans colonies significantly and improved clinical parameters in patients with elevated plaque accumulation.     

Histochemically-reactive zinc in amyloid plaques, angiopathy, and degenerating neurons of Alzheimer's diseased brains

Excess brain zinc has been implicated in Alzheimer's neuropathology. Here we evaluated that hypothesis by searching the brains of Alzheimer's patients for abnormal zinc deposits. Using histochemical methods, we found vivid Zn2+ staining in the amyloid deposits of dense-core (senile) plaques, in the amyloid angiopathy surrounding diseased blood vessels, and in the somata and dendrites of neurons showing the characteristic neurofibrillary tangles (NFT) of Alzheimer's. In contrast, brains from age-matched, non-demented subjects showed only occasional staining for Zn2+ in scattered neurons and possible plaques. A role of abnormal zinc metabolism in Alzheimer's neuropathology is suggested.     

Quantitative studies on the relationship of fibrinogen and “fibrin” in intima and atherosclerotic plaque

This study was undertaken to determine if there is a direct correlation between severity of a plaque and its fibrin and fibrinogen content. The amount of fragment D antigen per mg protein of the intima-media layer of the human aorta was determined by quantitative immunoelectrophoresis and was measured as the salt soluble fraction (fibrinogen) and, after extraction, as the plasmin solubilized fraction (“fibrin”). The subjects were apparently healthy but died as result of a traumatic incident. Paired controls consisted of samples of grossly healthy tissue adjacent to the plaque. The “fibrin” or fibrinogen of uninvolved intima did not increase with age. The fibrinogen content could not be correlated with severity of the plaque but there was a significant correlation with “fibrin”. “Fibrin” was significantly decreased in grade 1 lesions. The results are not consistent with the thrombotic theory of plaque formation.     

An evaluation of the acidogenic potential of asthma inhalers

AIM: The aims of the present study were firstly to investigate the inherent pH and titratable acidity of commercially available paediatric asthma inhalers in the United Kingdom and secondly to assess their in vivo acidogenic potential (saliva pH and plaque pH (PpH) tests) in a group of healthy adult volunteers. MATERIALS AND METHODS: Manually actuated metered dose inhaler (MDI) and dry powder inhaler (DPI) formulations of all available preventor (glucocorticoids, disodium chromoglycate), reliever (beta(2) agonists) and combination asthma medication were investigated. The inherent pH and titratable acidity of 18 inhalers were determined and analysed using t-tests, ANOVA and post hoc Tukey's tests. Following this the oral pH responses after inhaler use were assessed in 14 healthy adult volunteers (complying with the FNDH criteria, 1985) who participated in a random blind study to determine both the salivary pH (SpH) and plaque pH following inhaler use. Non-parametric tests of significance (Mann-Whitney and Wilcoxon Signed-Ranked Tests) were used to analyse pH responses according to vehicle of delivery (MDI/DPI), lactose content and generic drug. RESULTS: The inherent pH of the DPIs (n=8, mean pH=5.06) was significantly lower (P<0.005) than that of the MDIs (n=10, mean pH=6.45) and the titratable acidity of the lactose-based DPIs was twice that of the non-lactose-based DPIs (P<0.000). Lactose-based DPIs produced significantly lower salivary pH and plaque pH readings, greater maximum pH drops from baseline pH and larger areas below baseline pH in comparison with that of all other inhalers tested (P<0.05). All inhalers, however, failed to depress plaque pH below pH 6. CONCLUSIONS: Although none of the inhalers were able to demonstrate an acidogenic response below the "critical" pH, the substantial pH drops observed with the lactose-based DPIs may be an important consideration for enamel demineralisation.     

声学密度定量技术对颈动脉斑块致脑梗死的危险性的评价

目的　探讨声学密度定量技术评价颈动脉粥样斑块致脑梗死的危险性的价值。方法　分析脑梗死组与无脑梗死颈动脉组各类斑块的例数、狭窄程度 ,测定各类斑块声学密度值及复合斑块内各种回声面积占整个斑块面积百分比。结果　脑梗死组脂质斑块及复合斑块例数明显多于无脑梗死组 ,且复合斑块内低回声区域占整个斑块面积的百分比明显大于无脑梗死组。结论　声学密度定量技术能够评价颈动脉斑块的稳定性及危险性。     

动脉粥样硬化兔斑块易损性的血管内超声评价

目的应用血管内超声（IVUS）技术评价易损斑块的影像学特征。方法30只实验兔给予球囊损伤腹主动脉＋高脂饲料喂养，12周末将实验兔随机分为A、B两组，在A组腹主动脉斑块处转染携带人野生型P53基因的重组腺病毒载体，2周后给予所有兔中国斑点蝰蛇毒（CRVV）和组胺触发，14周末进行体表超声、血管内超声和病理学检查。结果A组斑块破裂率较B组显著增高（P〈0．05）。IVUS示斑块破裂组的血管外弹力膜面积（EEMA）、斑块面积（PA）、管腔面积狭窄百分率（LAS%）及偏心指数（EI）显著大于未破裂组（P〈0．01～0．05）；斑块破裂组的内一中膜厚度（IMT）、收缩期峰值流速（Vp）显著大于未破裂组，而平均回声强度的校正值（AIIc％）显著低于未破裂组（P均〈0．05）。结论应用野生型P53基因转染可导致斑块的不稳定性，IVUS能够准确识别易损斑块，为临床早期发现易损斑块并预测斑块破裂提供了可靠的方法。     

建立口内菌斑模型研究菌斑超微结构

目的:系统了解菌斑形成的超微结构。方法:建立一种口内的菌斑模型,并将1、5、9d形成的菌斑标本制成电镜切片后用透射电镜观察。结果:显示初期菌斑的细菌较少,主要为球状菌。随着时间的延长,细菌的数量和种类开始增加,出现丝状菌和杆状菌。成熟菌斑结构是两侧为丝状菌中间为球状菌的栅栏状结构,其中部分细菌会出现坏死的现象。结论:所建立的菌斑模型较接近天然菌斑结构,具有一定的参考价值。