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排序方式: 共有8257条查询结果,搜索用时 15 毫秒
81.
Susan K. Hummel DDS Victoria Marker PhD Larry Pace DDS Michael Goldfogle DDS 《The Journal of prosthetic dentistry》1997,77(6):568-572
Statement of problem. Controversy surrounds the use of hydrofluoric acid to prepare precementation surfaces of indirect composites.Purpose. This study was conducted to compare effects of combining hydrofluoric or orthophosphoric acid with microetching as precementation treatments.Material and methods. Nine specimens of three composite materials were prepared to simulate heat-cured indirect restorations. The specimen surfaces were prepared with one of three treatments. Adhesive Bond II and Twinlook cements were used to bond a phosphoric acid-etched disk of P50 to the treated surface. Analysis of variance and Scheffé tests were used to assess the bond strength data. Scanning electron microscopy and microscopic analysis of the fractured and treated surfaces were also performed.Results. Bond strengths for all surface treatments did not significantly differ. Hybrids had a higher bond strength with etching than microfills, and mechanical roughening produced the greatest bond strengths with microfills. Microetching with orthophosphoric acid produced higher bond strengths than microetching with hydrofluoric acid on hybrids.Conclusions. Acid etching alone is not sufficient to produce effective bond strengths, and hydrofluoric acid treatments are detrimental to the resin composite. (J Prosthet Dent 1997;77:568-72.) 相似文献
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The controversy surrounding fluoridation persists. In recent years opponents of fluoridation have resorted to the courts with increasing frequency and have achieved a few victories in the trial courts. To date, however, no appellate court has ruled against fluoridation. This article discusses the constitutional basis for the court decisions upholding fluoridation and the main arguments put forth by the antifluoridationists. Five of the more recent cases are summarized, as is the first fluoridation case to be appealed to the US Supreme Court. The article concludes that the legal validity of fluoridation in the United States has been thoroughly tested in the courts and confirmed. It appears that the antifluoridationists will concentrate their future legal attacks on the "harmful effects" of fluoridation on health and the environment. If they can convince the courts that even a few people were truly harmed, the delicate balance between the rights of the state to fluoridate in order to protect the public's health and the rights of the individual not to be harmed could well shift. In closing, the question is raised whether the US Congress has the power to pass legislation either to mandate or forbid fluoridation. 相似文献
85.
Shkolnikov VM McKee M Vallin J Aksel E Leon D Chenet L Meslé F 《International journal of epidemiology》1999,28(1):19-29
BACKGROUND: The dramatic increase in mortality in Russia and Ukraine in the late 1980s and 1990s has been due to increases in certain causes of death, particularly cardiovascular disease and accidents and violence. In contrast, there has been a slight fall in mortality from cancer. METHODS: This paper presents an analysis of trends and patterns in cancer mortality and examines four possible explanations for its recent fall: changes in data collection; cohort effects; competing mortality from other causes of death; and improvements in health care. RESULTS: All contribute to some extent to the observed changes, with each affecting predominantly different age groups. There is evidence of a significant underrecording of cancer deaths among the elderly especially in rural areas and of significant changes in coding practices in the early 1990s. Competing mortality from cardiovascular diseases and accidents can explain some reduction in male deaths from cancer in middle age. Birth cohort effects can explain some reduction among males after early middle age and among females at all ages. The impact of changes in health care are more difficult to identify with certainty but there is evidence of reduced deaths from childhood leukaemia. IMPLICATIONS: Recent changes in mortality in Russia are complex and their understanding will require a multidisciplinary approach embracing demography, epidemiology and health services research. 相似文献
86.
Differentiated in vivo skin penetration of salicylic compounds in hairless rats measured by cutaneous microdialysis. 总被引:1,自引:0,他引:1
Lene Simonsen Aksel J?rgensen Eva Benfeldt Lotte Groth 《European journal of pharmaceutical sciences》2004,21(2-3):379-388
The purpose was to investigate the in vivo skin penetration of four 14C-salicylic compounds using microdialysis and to relate dermal concentrations to structural features. Furthermore, to compare two in vivo retrodialysis recovery methods for estimation of true unbound extracellular concentrations. Microdialysis probes were inserted in the dermis of hairless rats. Equimolal 14C-salicylic formulations were applied topically and dialysate sampled consecutively for 4h. True extracellular concentrations were estimated by retrodialysis by drug method (the 14C-salicylic compounds themselves) and by retrodialysis by calibrator method (3H-salicylic acid as internal standard). Probe depth was measured by ultrasound scanning. High dermal concentrations were found after application of 14C-salicylamide (low protein-binding) and the lipophilic ester 14C-butyl salicylate, which was completely hydrolysed to 14C-salicylic acid during skin diffusion. Protein binding and dissociation may explain the lower dermal concentrations of 14C-salicylic acid and 14C-diethylamine salicylate, respectively. Probe depth did not significantly influence dialysate concentrations. The two in vivo recovery correction methods did not reduce the variation in concentration-time curves. In conclusion, differentiated penetration kinetics was found ranking: 14C-salicylamide >/= 14C-butyl salicylate > 14C-salicylic acid > 14C-diethylamine salicylate. Dermal concentrations were related to structural features of the model compounds. The two correction methods performed alike; however, the calibrator method has the advantage of serving as a quality control during experiments. 相似文献
87.
Merve Osoydan Satici Mehmet Muzaffer slam Gokhan Aksel Serkan Emre Eroglu 《Malawi medical journal : the journal of Medical Association of Malawi》2022,34(3):204
Angina bullosa haemorrhgica is a relatively uncommon condition characterized by blood-filled subepithelial lesions in the oral mucosa that is idiopathic and not caused by a systemic disease or a hemostatic abnormality. Middle-aged and elderly patients are usually affected and lesions heal spontaneously without scarring. A rapidly expanding hemorrhagic blister in the oropharynx can induce upper airway obstruction, so recognizing the lesion as soon as possible is essential. Because of its rarity, we wanted to highlight a 42-year-old male patient who presented with hemorrhagic bullae associated with insignificant local trauma in the oral mucosa and to emphasize that Angina bullosa haemorrhagica is a rare but recognizable lesion that clinicians should be aware of. 相似文献
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Gabriel Hernandez Machado de Souza DDS Luiz Carlos de Lima Dias-Junior DDS MSc PhD Renata Gondo Machado DDS MSc PhD Gabriela Pasqualin Ghidini DDS MSc Mariana Comparotto Minamisako DDS MSc Marcio Toshio Umeda Takashima MD Nayara Cardoso Cábia BMedPhys Ricardo Machado DDS MSc PhD Cleonice da Silveira Teixeira DDS MSc PhD Lucas da Fonseca Roberti Garcia DDS MSc PhD 《Journal of esthetic and restorative dentistry : official publication of the American Academy of Esthetic Dentistry ... [et al.]》2024,36(6):941-950