85 research outputs found
Adsorption of parotid saliva proteins and adhesion of Streptococcus mutans ATCC 21752 to dental fiber-reinforced composites.
The use of fiber-reinforced composites (FRC) in dentistry has increased during recent years. In marginal areas of crowns and removable partial dentures the fibers may become exposed and come into contact with oral tissues, saliva, and microbes. To date, few articles have been published on oral microbial adhesion to FRCs. The aim of this study was to compare different FRCs, their components, and conventional restorative materials with respect to S. mutans ATCC 21752 adhesion and adsorption of specific S. mutans binding proteins. Surface roughness of the materials was also determined. Four different FRCs, a restorative composite, and a high-leucite ceramic material were studied. Polyethylene FRC was found to be significantly rougher than all other materials. Aramid FRC also showed higher surface roughness in comparison with all materials but polyethylene FRC. Without a saliva pellicle, adhesion of S. mutans coincided with surface roughness and polyethylene and aramid FRC promoted S. mutans adhesion better than the other smoother materials. In the presence of salivary pellicle, ceramic and polyethylene FRC bound more bacteria than the other materials studied. Higher quantities of S. mutans binding proteins in the pellicles may in part account for the higher S. mutans adhesion to saliva-coated ceramic and polyethylene FRC.</div
Early plaque formation on fibre-reinforced composites in vivo.
AbstractIn the present
study, two different fibre-reinforced composites (FRCs) (glass and
polyethylene FRC), dental ceramic and restorative composite were
compared with respect to early plaque formation in vivo. Disc-shaped
specimens were randomly distributed among the upper first and second
molars of 14 healthy adult volunteers. Plaque samples were collected 24 h
after the attachment of the specimens. Mutans streptococci (MS),
non-mutans streptococci and total facultative bacteria were cultured.
The plaque recovered from polyethylene FRC harboured significantly more
MS than the plaque of ceramic, restorative composite and glass FRC. For
the counts of non-mutans streptococci and total facultative bacteria,
polyethylene FRC showed the highest counts, and ceramic showed a trend
towards lower counts. The amount of plaque accumulation showed an
association to the earlier reported surface roughness values of the
studied materials. It was concluded that in the oral environment,
polyethylene FRC promotes plaque accumulation and adhesion of MS more
than glass FRC, restorative composite and dental ceramic. Glass FRC
resembles restorative composite with respect to plaque accumulation and
the adherence of MS.</div
Ultrastructural Observations on Bacterial Invasion in Cementum and Radicular Dentin of Periodontally Diseased Human Teeth
Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/141124/1/jper0493.pd
Xylitol concentrations in artificial saliva after application of different xylitol dental varnishes
Neonatal mortality risk for vulnerable newborn types in 15 countries using 125.5 million nationwide birth outcome records, 2000-2020.
OBJECTIVE: To compare neonatal mortality associated with six novel vulnerable newborn types in 125.5âmillion live births across 15 countries, 2000-2020. DESIGN: Population-based, multi-country study. SETTING: National data systems in 15 middle- and high-income countries. METHODS: We used individual-level data sets identified for the Vulnerable Newborn Measurement Collaboration. We examined the contribution to neonatal mortality of six newborn types combining gestational age (preterm [PT] versus term [T]) and size-for-gestational age (small [SGA], 90th centile) according to INTERGROWTH-21st newborn standards. Newborn babies with PT or SGA were defined as small and Tâ+âLGA was considered as large. We calculated risk ratios (RRs) and population attributable risks (PAR%) for the six newborn types. MAIN OUTCOME MEASURES: Mortality of six newborn types. RESULTS: Of 125.5âmillion live births analysed, risk ratios were highest among PTâ+âSGA (median 67.2, interquartile range [IQR] 45.6-73.9), PTâ+âAGA (median 34.3, IQR 23.9-37.5) and PTâ+âLGA (median 28.3, IQR 18.4-32.3). At the population level, PTâ+âAGA was the greatest contributor to newborn mortality (median PAR% 53.7, IQR 44.5-54.9). Mortality risk was highest among newborns born before 28âweeks (median RR 279.5, IQR 234.2-388.5) compared with babies born between 37 and 42 completed weeks or with a birthweight less than 1000âg (median RR 282.8, IQR 194.7-342.8) compared with those between 2500âg and 4000âg as a reference group. CONCLUSION: Preterm newborn types were the most vulnerable, and associated with the highest mortality, particularly with co-existence of preterm and SGA. As PTâ+âAGA is more prevalent, it is responsible for the greatest burden of neonatal deaths at population level
Adverse maternal, fetal, and newborn outcomes among pregnant women with SARS-CoV-2 infection: an individual participant data meta-analysis.
INTRODUCTION
Despite a growing body of research on the risks of SARS-CoV-2 infection during pregnancy, there is continued controversy given heterogeneity in the quality and design of published studies.
METHODS
We screened ongoing studies in our sequential, prospective meta-analysis. We pooled individual participant data to estimate the absolute and relative risk (RR) of adverse outcomes among pregnant women with SARS-CoV-2 infection, compared with confirmed negative pregnancies. We evaluated the risk of bias using a modified Newcastle-Ottawa Scale.
RESULTS
We screened 137 studies and included 12 studies in 12 countries involving 13 136 pregnant women.Pregnant women with SARS-CoV-2 infection-as compared with uninfected pregnant women-were at significantly increased risk of maternal mortality (10 studies; n=1490; RR 7.68, 95% CI 1.70 to 34.61); admission to intensive care unit (8 studies; n=6660; RR 3.81, 95% CI 2.03 to 7.17); receiving mechanical ventilation (7 studies; n=4887; RR 15.23, 95% CI 4.32 to 53.71); receiving any critical care (7 studies; n=4735; RR 5.48, 95% CI 2.57 to 11.72); and being diagnosed with pneumonia (6 studies; n=4573; RR 23.46, 95% CI 3.03 to 181.39) and thromboembolic disease (8 studies; n=5146; RR 5.50, 95% CI 1.12 to 27.12).Neonates born to women with SARS-CoV-2 infection were more likely to be admitted to a neonatal care unit after birth (7 studies; n=7637; RR 1.86, 95% CI 1.12 to 3.08); be born preterm (7 studies; n=6233; RR 1.71, 95% CI 1.28 to 2.29) or moderately preterm (7 studies; n=6071; RR 2.92, 95% CI 1.88 to 4.54); and to be born low birth weight (12 studies; n=11â930; RR 1.19, 95% CI 1.02 to 1.40). Infection was not linked to stillbirth. Studies were generally at low or moderate risk of bias.
CONCLUSIONS
This analysis indicates that SARS-CoV-2 infection at any time during pregnancy increases the risk of maternal death, severe maternal morbidities and neonatal morbidity, but not stillbirth or intrauterine growth restriction. As more data become available, we will update these findings per the published protocol
Hydrolysis of Îł -glutamyl linkages by Fusobacterium nucleatum
The cell extracts of two human oral strains (FN2 and FN3) of Fusobacterium nucleatum displayed exceptionally high Îł -glutamylpeptidase activity as determined with N-Îł - l -glutamyl-2-naphthylamine as substrate. This activity was so dominant that the hydrolysis of other N -aminoacyl-2-naphthylamines progressed at a rate <10% of the former. Two major enzymes (I and II) were partially purified from FN2. I had a molecular weight of 115,000 and did not hydrolyze Îł -glutamylcysteinylglycine (glutathione). II had a molecular weight of 70,000 and rapidly liberated only glutamic acid from glutathione. Strain FN3 contained several enzymes hydrolyzing Îł -glu-2NA. Direct anion exchange chromatography of FN3 cell extracts separated one enzyme that liberated both glutamic acid and glycine from glutathione, one that was inactive against glutathione (but hydrolyzed Îł -glu-2NA), and one that liberated only glutamic acid. Although Îł -glu-2NA was a good synthetic substrate, glutathione was hydrolyzed at least 500 times faster by an enzyme present in both strains. These results indicate that the presence of Îł -glutamylpeptidase activity is very characteristic of these F. nucleatum strains.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/41334/1/284_2005_Article_BF02094016.pd
Vulnerable newborn types: Analysis of population-based registries for 165 million births in 23 countries, 2000-2021.
OBJECTIVE: To examine the prevalence of novel newborn types among 165âmillion live births in 23 countries from 2000 to 2021. DESIGN: Population-based, multi-country analysis. SETTING: National data systems in 23 middle- and high-income countries. POPULATION: Liveborn infants. METHODS: Country teams with high-quality data were invited to be part of the Vulnerable Newborn Measurement Collaboration. We classified live births by six newborn types based on gestational age information (preterm 90th centile) for gestational age, according to INTERGROWTH-21st standards. We considered small newborn types of any combination of preterm or SGA, and termâ+âLGA was considered large. Time trends were analysed using 3-year moving averages for small and large types. MAIN OUTCOME MEASURES: Prevalence of six newborn types. RESULTS: We analysed 165â017â419 live births and the median prevalence of small types was 11.7%â-âhighest in Malaysia (26%) and Qatar (15.7%). Overall, 18.1% of newborns were large (termâ+âLGA) and was highest in Estonia 28.8% and Denmark 25.9%. Time trends of small and large infants were relatively stable in most countries. CONCLUSIONS: The distribution of newborn types varies across the 23 middle- and high-income countries. Small newborn types were highest in west Asian countries and large types were highest in Europe. To better understand the global patterns of these novel newborn types, more information is needed, especially from low- and middle-income countries
Adverse maternal, fetal, and newborn outcomes among pregnant women with SARS-CoV-2 infection: an individual participant data meta-analysis.
INTRODUCTION: Despite a growing body of research on the risks of SARS-CoV-2 infection during pregnancy, there is continued controversy given heterogeneity in the quality and design of published studies. METHODS: We screened ongoing studies in our sequential, prospective meta-analysis. We pooled individual participant data to estimate the absolute and relative risk (RR) of adverse outcomes among pregnant women with SARS-CoV-2 infection, compared with confirmed negative pregnancies. We evaluated the risk of bias using a modified Newcastle-Ottawa Scale. RESULTS: We screened 137 studies and included 12 studies in 12 countries involving 13 136 pregnant women.Pregnant women with SARS-CoV-2 infection-as compared with uninfected pregnant women-were at significantly increased risk of maternal mortality (10 studies; n=1490; RR 7.68, 95% CI 1.70 to 34.61); admission to intensive care unit (8 studies; n=6660; RR 3.81, 95% CI 2.03 to 7.17); receiving mechanical ventilation (7 studies; n=4887; RR 15.23, 95% CI 4.32 to 53.71); receiving any critical care (7 studies; n=4735; RR 5.48, 95% CI 2.57 to 11.72); and being diagnosed with pneumonia (6 studies; n=4573; RR 23.46, 95% CI 3.03 to 181.39) and thromboembolic disease (8 studies; n=5146; RR 5.50, 95% CI 1.12 to 27.12).Neonates born to women with SARS-CoV-2 infection were more likely to be admitted to a neonatal care unit after birth (7 studies; n=7637; RR 1.86, 95% CI 1.12 to 3.08); be born preterm (7 studies; n=6233; RR 1.71, 95% CI 1.28 to 2.29) or moderately preterm (7 studies; n=6071; RR 2.92, 95% CI 1.88 to 4.54); and to be born low birth weight (12 studies; n=11â930; RR 1.19, 95% CI 1.02 to 1.40). Infection was not linked to stillbirth. Studies were generally at low or moderate risk of bias. CONCLUSIONS: This analysis indicates that SARS-CoV-2 infection at any time during pregnancy increases the risk of maternal death, severe maternal morbidities and neonatal morbidity, but not stillbirth or intrauterine growth restriction. As more data become available, we will update these findings per the published protocol
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