Objectives: To determine the reduction in composite polymerization stress through the addition of non-bonded microfiller particles.
Methods: Microfillers that were unsilanated, silanated, and treated with a nonfunctional silane were added to dental resin and to a small-particle composite. The contraction stress generated by these materials was measured by polymerizing them between glass plates mounted in a mechanical testing machine. The maximum force was recorded 15 min after photo-initiation. Results were analysed by ANOVA (analysis of variance)/Turkey's test (p < or = 0.05).
Results: The addition of non-functional silanated microfillers to dental resin resulted in a significant 50% decrease in polymerization stress. The addition of unsilanated microfillers did not reduce the contraction stress. When added to small-particle composite, the unsilanated microfillers produced a significant 30% reduction in contraction stress compared to the composite containing silanated microfillers. The non-functional silanated microfillers did not reduce the contraction stress in the small-particle composite.
Significance: The polymerization shrinkage of dental composite can impose high levels of stress on the tooth surfaces to which it is bonding. This contraction stress can lead to failure of bond formation with the surrounding tooth structure. Microfiller particles that are not bound to the resin matrix might provide sites for relief of internal stresses, significantly reducing contraction stress in dental composite.
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http://dx.doi.org/10.1016/s0109-5641(98)00036-0 | DOI Listing |
Sci Rep
December 2024
Division of Radiation Oncology, Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.
Aggressive breast cancers often fail or acquire resistance to radiotherapy. To develop new strategies to improve the outcome of aggressive breast cancer patients, we studied how PARP inhibition radiosensitizes breast cancer models to proton therapy, which is a radiotherapy modality that generates more DNA damage in the tumor than standard radiotherapy using photons. Two human BRCA1-mutated breast cancer cell lines and their isogenic BRCA1-recovered pairs were treated with a PARP inhibitor and irradiated with photons or protons.
View Article and Find Full Text PDFBiomimetics (Basel)
December 2024
Department of Clinical Sciences and Stomatology, Università Politecnica delle Marche, 60121 Ancona, Italy.
Marginal enamel fractures (MEF) are a common clinical concern in dentistry, particularly in anterior teeth. These fractures occur at the enamel margins and their etiopathogenesis involves a complex interplay of mechanical, chemical, and biological factors. The ongoing research focuses on an overview of MEF to improve the knowledge about this condition.
View Article and Find Full Text PDFAm J Physiol Cell Physiol
December 2024
Department of Evolution, Ecology, and Organismal Biology, University of California, Riverside, Riverside, California, USA.
The optimum length for force generation () increases as activation is reduced, challenging classic theories of muscle contraction. Although the activation dependence of is seemingly consistent with length-dependent Ca sensitivity, this mechanism can't explain the apparent force dependence of , or the effect of series compliance on activation-related shifts in . We have tested a theory proposing that the activation dependence of relates to force depression resulting from shortening against series elasticity.
View Article and Find Full Text PDFClin Microbiol Infect
December 2024
Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, United Kingdom.
Objectives: The objectives were to determine the structure of training programmes and assessment of physicians training to become infectious disease (ID) specialists in Europe in early 2024, and to document the provision of specialists, trainees and training centres in each country.
Methods: Delegates to the ID Section and Board of the European Union of Medical Specialists (UEMS) entered national data on a web-based survey tool in late 2023-early 2024. Results were compared to UEMS recommendations on the structure and content of postgraduate training in ID in Europe (2018), and to results of a similar survey in early 2021.
Circulation
January 2025
Division of Cardiology, Department of Medicine, Emory Clinical Cardiovascular Research Institute; and Emory University School of Medicine, Atlanta, GA (L.S.S.).
There is a new awareness of the widespread nature of metabolic dysfunction-associated steatotic liver disease (MASLD) and its connection to cardiovascular disease (CVD). This has catalyzed collaboration between cardiologists, hepatologists, endocrinologists, and the wider multidisciplinary team to address the need for earlier identification of those with MASLD who are at increased risk for CVD. The overlap in the pathophysiologic processes and parallel prevalence of CVD, metabolic syndrome, and MASLD highlight the multisystem consequences of poor cardiovascular-liver-metabolic health.
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